.Net Foundation Design Reviews, 9 Feb 2016

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From YouTube: .NET Core Design Reviews: ADO.NET

Description

In this review, we’ll take a look at the revised proposal to get schema information:

https://github.com/dotnet/corefx/issues/5915

To address #3423: A replacement API for DataReader.GetSchemaTable().

A

So we're not live close.

B

C

Just fold it again.

A

Closed the issue again, good.

D

A

Okay I'm in the browser tab, not they should sell, although that happened all those in the comment button Eric way too close to each other, all right, so all right guys unless we already had like a one design view on this one. This is basically the revised proposal. Ever she shared screen.

C

A

We can actually see the proposal.

A

So, based on a bunch of feedback, um you updated this report. We want to walk us through like what the major changes were. Yeah.

D

So Oh, essentially via we had ironed out a lot of things on, and there were suggestions that go and figure out the names and how the port will look from a dotnet go to be next and how intro interrupt will work so I just walk through the code snippets and explain what they are all about. So the first data structure is the DD column which we had spect out, an issue 3 for 23 and it's a bunch of gators and setters and the there's a indexer as well on this. So there we are. These.

D

These properties are present in the data structure, are some of the common properties that we see in the DB columns for all the databases and hence for all the providers. And let's say: if sequel wants to provide something extra and wants to expose it to the lower level libraries which do not come about sequel, then they can expose it using the Gator. If you can, you stroll up a bit I want.

B

D

See the score data structure, yeah yeah, so that's the accessor for the indexer which, through which we can access the extra properties which may for some reason we needed by the lower levels. But this is a set of common properties that we had decided upon with the community on 3403. And what is the type.

E

Of the object returned from the index, it can be anything so is that basically, the data in the database yeah, it's like a binary representation of of the object.

D

Yes, so I mean it depends our database, but this is not really the data. This is the metadata for theta. So let's say that sequel has one more tyranny: one more property to describe its column. Saying, let's say, is oh girl on this, but let's say if it has another property which is a pool, and then it has another property which is probably a string and then another in which are specific to sequel database. So it can expose those using the index so that we have and so can, post array or my sequel. So.

E

I understand that its metadata, but when, when it's stored in the database yeah, the data would be some primary yeah for more. It would be all strings because I wonder whether so would not make sense to just return the string here and if it's a name it's you know it's a string representation of an intended crypto parts or it really does make sense to expose it as an object. So.

D

It can so it can be anything okay. How to stored in the database is restored and we see all the metadata in a view in a database and view has different columns which, which can have their own types, so they could be a bull string and int or whatever the column signifies.

D

This is so oh yeah, so, ideally which it shouldn't be that okay I'm returning a true as a string. It should be under turning it to us. Yeah, yeah, okay,.

A

This is the other way is the view that sequel would also survive from that class. Yes, ullam. That would give you a strongly typed, just those yes yeah there, except and.

D

So that was the data structure, though I will go down to the proposal.

A

Christian I have like why they all sellable other way around. They all said about why they virtual because.

D

Of two things: they're settable, because this data structure can be used, as is by a provider, to pass around its data. So it may not. Sequel may not create security, be column, it can use a DB baller and but in case it wants to add most from strong types to it. They can they can derive from class, but.

E

Then the provider would implement a subsidized to be able to do it, so the setters could be affected, protected, correct, yes or should be even because the you probably don't want the consumers.

A

To be able to see a like if the comment, for example, they say you return a read-only collection of TV column right, you don't want people to be able to set its it's true for it. Since a lot of part of the change.

F

I'm in Dos Equis.

F

Basically, my questions recently right. The question is why I could be. We need to have that object please. So because, at the end of the day you will you will offer I mean we will I mean you create your implementers if the Fred, like sequel, DP colors and has their own properties right, so I thought instead of having weekly tab, we just support the strongly pad, but at the end of the day, they didn't need to check whether whether the DP column is a type of sequel to be column and use.

F

The specific custom security p columns, the.

A

Other question I would have liked you to expose an indexer. It seems like you also want to.

D

Expose the possible keys, so the default implementation skied on the names of these properties, so.

A

True, but my question is: it's a get an instance of DB calapan for diagnostic purposes. It may be useful to know which other keys are in that, like which other four podiums can access like. How would I eat, though its sequel has a magic.

A

You know property called foo like how would I discover that I mean like I mean I would say if you, if you give people basically key based access mechanism, I think you want to expose the key somehow as well yeah, so otherwise, maybe whether to just remove the mix it all together and say. Well, you have to know that it is a sequel to be cut them cost of that type. And then what? Obviously you know all the properties.

F

At that point, otherwise they need to check it all right if I can get this property and then I to something. But if you strongly type, then there will be no problems too. Oh that's the other question. What, if the cover it.

A

Doesn't exist, you throw do you get now. Oh.

E

Right now up proposals to given up and what we can can some property have the power you know or.

D

E

A

D

Have okay, you've already called default value? Okay, so.

E

D

The model difference between.

C

D

E

Getting detailed value versus nothing system, oh.

D

Not in any of these properties that we have there they, except for know there are, there- is a string which, which can have a null value in it, which means that it doesn't exist. So if a null is returned, then it can mean two things: either it does not exist or a.

D

It was not supported by whatever provided provider you're using either, which phase add value will never be.

E

Available from the provider, so you know like I, don't have a strong opinion, but if you want to let people differentiate between those two, the two cases you may want to do it? Okay, but maybe it's okay and you know in the future. If you discover a case where you need to distinguish, then you had additional property code is available or something like this. So another thing we discussed this, you know receptors being protected and so on and so on, but I just noticed those a virtual methods.

E

They are not I mean virtual properties, they are not non-virtual properties of fields, in which case you kind of don't need setters. At all. Correct this. My question, I would, I would say you.

A

Either settle on, you have setters, which gives it just feels essentially, and that case I wouldn't make them on virtual, because it makes sense to have the virtual or you have no status in the magnet virtual I wouldn't do both I would make a decision over the other I personally would lean towards virtual with getters. Only because I think the pattern that you want to basically enforce is that it has a value. The bed. You can really never change so.

D

Let's just think out loud, so yes of intention of this to be modified, as is only by the providers and not by the consumers or the producers, so which makes sense to not have the properties being set outside, because so the producer should only be able to set this now if they are protected, the setters.

D

If the property and the setters are protected, then how then they will. They need to subclass it right, doggy able to correct right, but the intention is to allow DB column to be used, as is without need, two subclasses. So why are they either 12? What's.

E

The case where you want to override this property behavior, why.

D

Yeah, they don't need to be virtual, even a first different, a subclass. They can be accessed by the subclasses on yeah.

E

Yeah, so if they are not the rich world, honestly I understand that you would like people to be able to use it without inheriting yeah but I. I think this enormous value in just making SS protected. It makes it very clear what the usage for the majority of our customers. You know it would be clear that they are not supposed to be selling these values, and then there are only few people who will be implementing custom. You know, database providers, so for them to inherit is not a big deal. Wait.

E

So are you suggesting that I.

D

Would just make them nine through twelve and lex public, better protected, said all right and take care of storing the values internally and and.

E

If you know like, because if you want it to allow people not to inherit from this type, you would have to have a constructor and then constructor would have to have some. You know take a dictionary that, specifically to a way to set all the these properties during construction, then you don't have to incur it. You just create one. You pass all the properties now you have and.

D

Logan is in the in the constructor, read Sandra dictionary, which has all these properties set. Why why? Why would that.

E

Be necessary, I don't follow, so it gives you the advantage that now you don't have to incur it from the B color, but you still preserve the property. That said, there's an ass public and.

D

So the dictionary can have extra values also, and are you recommending that we expose her through the indexer.

E

Yes, so that was that's actually touching on the related question. If I use the indexer and I pass one of the existing properties, is it going to work or not? Yes, so all these all properties, I can access through the indexer. Yes, you see, so you could have a constructor. It just takes a dictionary.

E

Yeah has all the values and it initializes like a dictionary inside this object and then the strongly typed properties of just helpers, they basically just index into the dictionary and- and you know, has the value so that I type so but you're.

D

The problem, I see, of the reason I didn't want to get the dictionary there is to not manage the storage of how this is to be done. So let's say: if you want us, if you want to specialize that you subclass it and you create your own storage and put it there right now.

D

The implementation is that you, you switch on the property news and return the property itself, but if you want to have it more specialized or have your own storage or two wanna do other things with the indexer, then you initialize your own storage internally and manage as you're ready have storage in the face that correct. So there is no storage story in this is only the properties that are. There is no extra dictionary.

D

E

I thought you were saying that you would like people to be able to completely change storage for all of the properties. No.

D

For causing index properties that if they want to use a dictionary for it, so let the flexibility on the beyond subclass, rather than us, taking the owners of putting it in the base class. So what do you use today for the it's, a bunch of switch switch case, statements on the existing properties and that's what DB column the base class needs to expose? Oh because.

E

The IC the base leg doesn't have any any extra stocks. Okay, so.

C

E

Just doesn't make sense to go. Acts have to just accuse three and.

C

Dispatch to the base here.

D

Yeah, so that's why not externally and just FX in general, the question.

A

Is like how we saw senses it is this area and I mean if you again, I got the impression last I'm like if you do this a lot to a query execution, and ideally you care that DB colors are not super expensive, I yeah, everybody else who hold on to a dictionary that has yet, if the single value boxed or something right, but at the same time I mean it's. The trailer between flexibility and ease of use, like personally I, think super standpoint. The same of you know, connection string builder way.

A

Essentially everybody just deals with the stolen type properties, but charlie, I think, is essentially dictionary of key value, pairs, Oh type, the string, I. Think, and then you know at the end you just close to straight line, but I mean I. Think this one is very similar like it feels very much like. Okay, there is a uh you know, the majority of things that I care about our typed and for their manners.

A

I have an escape hatch, but then to me would just mean that the behavior is such that it behaves like a dictionary for the you know. The extra bait is and for the remainders it behaves like a strongly typed data structure, in which case I would probably go down. The path of saying you know, make all the fields so I make all the properties protect its edible, remove virtual and enforce that base types have to derive and then deal with that, because that this way I mean everything is a strongly typed feeling on the objects.

A

The override of this thing is as small as it possibly can be. um I mean you can potentially have a smarter data structure. If you make everything virtual by saying, oh I know the majority of fields are zero or you know smalls or whatever, and then I only have to allocate fields for the five things I care, but then they can be virtual.

A

The base that they have to be abstract so that the base that doesn't allocate an actual field and so on that point becomes harder to version yeah, so I, don't know like I would probably go down there, as I said, make everything on virtual protected setter, a virtual indexer, and that's it. Ok,.

D

So virtual indexer I'll remove the removal of virtual agreed upon and protected sectors. The.

A

Only other thing I will consider is that CD color in fluent I dictionary of string, comma object and it becomes a dictionary in itself or you delete your face. Well, you can still them in at the same way you do today, but you basically get the semantics that you would expect from a dictionary, which means I will probably implement a good shell on the method explicitly but would leave the indexer. You know count the keys try get and then you can pretty much address all the issues we just talked about. So.

D

Sad if, if I implement from my dictionary, the only method, I foresee being used as the indexing or the Gator or Gator on the index, uh because all the try get by them index I mean at this one. You.

A

Get a defined behavior if the key doesn't exist, in example, throw yes! If.

E

You, if you don't want for you, just try it try again I just so. The only is some one concern I would have. Is that now implementing a custom, one would be a bit more tricky. While you have to make sure that, for example, the count is always consistent, but now you have the dictionary implemented by the base type that doesn't know about the storage in the subtype. So somehow you have to communicate to the basic implementation of dictionary that there's additional storage.

E

It needs to take these things into the account when it returns to the community. You will have to do they. Only two things you have to have virtual is essentially try. Cadbury.

A

A

Probably another message that would just give it a dumb baby action keys. What about the count? The count is the base types number of keys Plus that are whatever the virtual method, which rises the number of kids, because you always have 30 other ones right.

E

What do you mean? You always get 30 M elements? You can never add additional storage to their subtype. Yes, they can be not a dictionary. They can be just to two additional fields. Now you have to communicate it to the base type implementation that you have more, but one is in the derived type. Let's say the raft of eggs as three properties.

A

Right that means the derives that knows about to be possible keys. The base have already deals with those. Let's say this is 20 27, then the total count is 30. Okay, so that's easy to compute, just basically the base of know you.

E

Know how many it has it calls the virtual that gives you the keys. What about the enumerator? How would the enemy rated now walk the additional fields as well, in addition to the ones in the base type I think we is it be almost every single method on the dictionary in the dictionary implementation somehow would have a they would have to be a hook such that the subtype can communicate, that it has more slowly.

A

Step is the keys plus the override for the getting the value. This is only tues easily. Everything else can be held by the pizza.

E

But you just mentioned that the count would need to be also yeah. The maester has to end of the count, so they derive.

A

Time only has to override a method that says, give me the keys, so you return.

E

Foucault mubarak Homer fall, so the comes would always it call first cut keys and then call length on it. Those are slated expense.

A

I, don't know any I, really an amazing considering from a design standpoint, yeah.

D

I mean of Y, so the reason, one of the reasons for this and Exodus that in case of an attribute from a subclass, needs to be kind of needs to be consumed by the base class, and those cases will be very specific that it's not that you're going to be going over all the attributes and getting them and doing something you got to know what they are. So essentially, the consumer will need to be aware of what it wants to consume.

D

So I think the dictionary will be a bit excessive and implementing this as a dictionary. So what I would say is it.

A

Sounds to me like, then, you shouldn't have an index a period. That's that's what it sounds like because I mean if you're saying you have to know the time, then I will say: don't have an indexer, basically just say it's a strongly type thing period, if there's extra properties there on the derived type and if you want to process them after not the derives, have gift to North properties.

A

So, let's, if I better, to have I, think if you have then dynamic approach to get the values, I would rather say it behaves and smells and behaves like an index, um and then you can also get if you implement the x-ray. In our dictionary you get other niceties in the IDE, but for example, if you actually hold on to a DB column in the debugger and you and you expand it well, the debugger knows it is phase as it is in its dictionary, you get the default.

A

Behavior of you see the key to the values, like all the things just really start working, and you basically get the benefit that everything shows up. Not just the property is right, but I would also agree with you that it seems pretty heavy weighting bit over engineered for this project. Lenses, which case I, would honestly just ate rippled index at entirely well removal of a mixer again again. What's the scenario for it like.

A

If you say you already have to know the types, then why can't you just cast the device time and access the poverty so.

E

You can forget, humble make the drive type, not public. That would be the scenario I'm not saying that I have an opinion on hot, although.

A

I would say that the general pattern and a do that is that the flighters have derivatives are always public. I would honestly say: I have.

D

A secret Nodine, my idea is to not depend on those under the right types. Libraries, so I only depend on the common and I have something which tells me. Ok, this is the entry point for your. You know the tassel.

A

At younger I agree that all about saying is that if you look at if the provider model that's the model you have, but you can choose to just code against the comment surface area, but you can always drop down to the dr types. If you need to right, there will be the same pattern here. Like you most of the things you expose on the base you in a special case, sequel or you just say it become as secretly big hug cause awesome, then any excess. The extra feel it to something.

D

Smart, it knows to say c, KU kala me as or column as DB, our security with Colin. You need to have a reference to the have, a reference on system data sea to find and and hence the other providers. So that is what the indexer tries to address.

F

But so my command file itself, like a reference to death, it's from fighters seems like that, but that's one of the key points and three four two three, and so basically they have two different libraries. One just depend on the tippy comments and someone possible detective is.

D

So otherwise you see the whole work we did on this library and creator. Sorry, this API, the first approach that have a schema generator I, don't know if you remember so that could have been possible, but the first blocker here is that the consumers don't need to know about the producers, but I think what you know is saying.

E

Is they kind of need to know in this case to access this property this indexer? They need to know so you kind of like pretending that they don't know, but they do they do yeah this. So they need to know.

D

Some detail about it at least what is that property that I'm trying to access and why I should even access it effort a special to that particular whatever other having.

E

Said that I my care level about whether we expose this property or not this low, but what I think we I would recommend this. Let's say: let's say you leave the property and in the future you discover that your customers want. You know the number of items in the dictionary and they need to enumerate keys and whatnot at that point, I think you should just at least follow the same API designers dictionary.

E

So this type starts looking as a dictionary and then, if you realize that you have many of the dictionary methods, just leave them in the interface, because you can always do it. If you take over me.

D

Basically, you're saying that, as an extension, if, if ever we have to add to the required I mean act in EP, is because of questions requirement for the dictionary.

E

I say exactly: let's say you should this type and then customers say: oh you know we would like to know. The number of items see that in the is the dictionary, correct, yeah, don't add the property called number of items in you know the number of properties as I I say, apoyo sound and then, if you discover that you keep adding lots of members that look like dictionary- and this starts being like a dictionary just implement this side, the chiller so I.

D

See so if it starts off like an eternity, go for the.

E

Interlaced ignorance and greed.

D

I do I totally. Oh.

C

Yeah what he says.

A

All right, okay, this to death; um no, no! The proposal.

A

Skinny, because am yeah.

C

A

D

So far, this is the interface that I want to introduce. It is called IDP, Colin schema, generator and I want to keep the name of tied to the column instead of the reader, because it's really getting the schema from the column and I believe that this may be more reusable and tying it to reader, and the method inside this is called get schema column, so I get column schema which are done.

D

The read-only collection of DB cards, and this is the interface which will be implemented by all the providers or TB data readers in the providers to be able to.

D

This is the example I put together that psycho datareader implements its subclasses DB dieter dieter and also implements an interface and hence exposes the schema using the read-only collection or the API in the interface. Now.

D

This is what the providers need to change the need to implement the interface and the API in there and when we, but to access this the producers they can access it through the DB data reader using the same method name, the same signature, which is mentioned below. Oh.

D

B

D

If I will introduce a DB data, reader extension, which exposes started with the same name, o.k column, schema and dixon single parameter, which is this DB data reader reader. And if it is an instance of the interface we return, the column schema. So otherwise it.

E

Is not implemented so is we discussed it last time that these changes you can make them in the third quarter correct like you can implement the interface? Yes, but nothing that net framework? Initially, yes, so the contract the.net call contract for this ap is will not have the interface implemented on the idea. Reader / not.

D

On the data reader for but with superior reader, showing sorry what about see you later see you later reader will need to short better.

A

They wouldn't work for full paragraph, because we can edit.

D

F

See, oh, the simple data reader doesn't need to have additional methods right. You just implement the interface, but that is the same problem. I think I.

A

Think what we said last time posted this type here dvd-r we do extensions, are there's two limitations: the limitation that you're strong here is accentuated on a core based implementation for the full framework version of this type. It will do the same check that you have here, but then the very next, instead of throwing not implemented exception, you would go back to the old schema api's and the depth down. So today, blind provide this time out of that. So, if you're running into containers, you.

D

Don't we don't have to change the data reader to get this is ABI I'll leave doesn't ruin the facade implementation. Not in this the partial facade, implementation, compassion, the mapping.

A

Well, the way I think about this is a maybe I would yeah I come on the truck facade for now, I got what I would just say. There's two assemblies, yes, one over basically have the same surface area. What implementation is for full framework which behaves in the way I just described. The other one is what club is implementation, which looks exactly like that? Yes, so it means on the full fabric. Implementation yeah see you.

B

A

Literally, doesn't have at the interface but Lee with every day extension still works because it folds back to the old schema APR engines. Now, if you look at the entire surface area of target of a euro debt between Aaron Berger nightcore, it's more consistent. If we don't have to expose the fact that sequel datareader encore implements the interface, because otherwise we have to reduce your new contract. So.

E

How will see well I think we we talked so I just wanted to make sure. I think this design is right, but I think we need to discuss the details of how they implement it. I thought we agreed that we will ship two different contracts, we're gonna ship, a contract in the existing generation. That does not implement the interface and then we cannot ship at contracts. That is a new generation that does implement the interface.

E

A

Oh, my understanding was they'd, be postpone that until bereft the rest, I, better I, don't know where yeah the second part we can post on yeah I, don't illogically. We I.

F

Think the second part will see a spin in the.

D

Bottom for Phoenix, the partner you're talking about falling back, is something that I envision would go into the facade with the partial facade, we're in the cause to the extension method will be caught and it will be implemented on top of da 24 dot 5 and which maps which falls back to the default implementation that we expose on the vessel and what compiles or builds but got at core is what you saw above, which will essentially throw an automated exception. If there is no interface but.

E

The thing is that so, let's say you implement this interface on sequel, datareader, right somebody who codes to the contracts but wants to run on that net framework. Yes, who write a line of code that casts say interracial either to the interface yeah and that will the failure.

E

That will not only fail on that network that will literally, like type not found exception on that this framework, which is bad. It's not that the cast will fire the type man found you. You know the loader will fail. So that's why I thought we talked that the contract will not have this interface implemented on this type. Yeah, therefore,.

E

About implementation will have it implemented, I think like that step back and sing in order to.

A

Get the picture here, you have to consider there's a difference between what implementation does and what the but what is exposed in the service area right, because the idea that we have is that we did we say, don't a corner and framework conceptual different platforms.

A

Now we designed on a core that essentially look at the assembly identities they like 95, ninety-eight percent or whatever I literally the same between for economic or which means, if you create a class library- and you say, I, only target dotnet core the amount of things you can do there, I literally more or less the exact same amount of things you can do as if you were created.

A

Portable librarians I want to target both so that the changes are minimal, so anytime introduce an API that is done, echo only that is in the conduct of chapter for Fair Work, and s toy basically becomes harder like it's not impossible for us, but it is, it makes it makes it easier to accidentally dependent on echo only behavior, which it all makes it very very hard for them to share any code before farewell. I understand.

D

These concerns for questioners are given an interface which, let's say we don't expose it on the surface area. Right now, I have a secret pine, which nice twist implement the same to face. Fish lies and data also just to make it fit the interface you should.

E

Expose it, what I'm saying is sequel date are either. You should not implement this interface in the contract, because, basically, if you do a task to this interface, you can do like a straight cast to this interface ojos. The metadata will tell the compiler the cast is fine, because the type implements this interface. You can just cast your recommendation.

D

E

It's going to fail because the actual implementation is.

D

That the framework will not have this interface effeminacy, so your recommendation is only in common, ok, so that no one can try to access secret data readers method directly by cos movement. Yes, but in a dollar framework, this implementation will be nice. Oh.

F

No, that's fine, but right someone.

D

If someone brings out that line, return costs, yes, column schema on concrete type of leader, a secret data reader. Then it will fail that five wording will just feel so. I.

F

Voice, the difference is the if, if the TD reader is the one who implemented but.

D

Don't expose it in the contract, non-explosive you'll be implemented, but cold exposure to the contract is what you.

E

Will basically have to have to dl ellsworth one for the contract, yeah one for the actual implementation and the contract? One will just not have the interface implemented. Ok,.

F

B

Yes, educating already have yeah just in the red folder, you have a CS file that defines your ships area. Don't have the thankfully.

E

Fix activity, computers and then second related question. I think you know in the reader you can have. If readers I data, DB Collins schema generator, blah blah blah, hey else, I, don't think you should throw not implemented exception. I! Think it's like something! What the heck is going on exception, because this branch should never be hit, like literally, should never, because this will be executing only on that that car and it will just succeed, no.

D

It can, it can be here, let's say, I have so. This is equal example that we are talking about a sequence DVD to provide, or no let's say, be a post-race provider and they haven't implemented the interface. So I gotta tell the consumer that this interface is not implemented by whatever provider you're trying to learn soon. I.

E

See I I think I, ok, I, agree because we not adding the interface to the base type in this generation, this generation they have to know to implement this interface. Therefore it can be the case that they don't yes, I wonder whether we should throw not supported yeah and.

A

Then maybe even I mean you can basic to the right up check yourself. You can just say before college is my 50k. Today there is a composite component infinity.

F

So this generation, you know what the secret is, the one who implemented right if poss, otherwise the sequel narrator cannot pump right.

F

So tell me: I mean English in this time being we're gonna, stick with this right, I defeat, pomsky, my generator, which is implemented by I'm, in which you know we're gonna, do single dad are either right. The.

E

Emulator either we were implemented. Yes, the contract for sequel data reader will not show it that it's implemented. Thank on.

A

Second thought, though, I think we should. We should have the Cure API year as well, because it's pretty impossible to write yourself Oh, knowing the difference if it is because basically I just thought is like if we throw you should have a method that says that's.

A

This guy's support schema information which are not in the frame with the answer is always going to be true and I don't need core its depending on what the implementation fit, and so we should probably give you that method as well, but though the nevada library, I get schema, something that all or you know it has has column schema or whatever is something like that? What supports columns? Oh hope, okay, I mean in.

D

The extension yeah.

A

Because they said.

C

D

So does not look in the future, so I'm going to need to talk about them, ah but.

A

It really is basically.

D

A

Is that you can avoid the exception by asking the question up front, the implementation is almost identical, 45 millions of always return. True, but nicoya just say: does this guy implement this interface and that's it? So it's literally two lines of code and they would never change. Okay,.

D

I mean I see a point, but if, if I take it forward, for example, I put this method and now I think that when we take it back to dot net full framework and / in the base class, this particular method yep, then we know that it is available. Yes to the end, in what do we do with this extension method? What is the placeholder for this extension method? Does it also make its way into dr.

D

desktop, or does it just stay in core on this extension, and I would say I will get, which is it the same way as the extension.

A

Method, which means, if we go into replaceable, focuses on the base type. Then you apply the same like worst case. Is the method work for sure in chip which are true? hmm Well, I think the problem is like, generally speaking, if you have, if you not support it means the onus is on you, the color, to know when it's safe to call this API.

A

How would you know it's safe to call without duplicating the logic of the implementation, and the only answer to that today would be, if you provide you method where you can ask which is basically take streams, but you can ask the stream I you mean only if so well, then cut don't call the right methods if you call the right methods. While then we throw not supported because you're called ride on a read-only stream and that's the same idea like I mean the caller.

A

Can you know, put the check up in the stack and then run with it or just ignore it, and they just do not support it at the right layer? The problem is, if you, if you want exception, that you cannot avoid it results in very unreliable, called, potentially a World War implemented.

D

And we throw Lord not supported for platform support code, but what about not implemented exception not implemented.

A

To be is almost like something you should never see in the fabric creates more likely user code. When you have a pen stand half they would ya. Don't think I should ever see that you should, if you throwing an exception issues, not.

E

Supported on supporters, nothing.

D

E

Is like oh well, let me just now implement you know like it's. The answer to not not implemented exception should be I go and I eat limited. So it's a place for it. It's essentially a placeholder application who track problems.

A

Okay, in fact, when you sort tools like we shopper, they will highlight but implemented s essentially a to blue marker, so I. Maybe it's not really for fiber code, this time uShip, you should not have to thin their only messed up.

A

D

D

Don't know I mean I I see your point but I'm not quite convinced just think of how you would write photo code. I.

A

Cocaina cope with you right if you were to implement it, say entity, framework or some sort of orem that that's deals with this high level schema informations like you would like what you would what you would end up. Writing is code like well I can't process pretty much anything I can do something more if you have schemer information.

A

So how do I avoid that Michael just blows up if you happen to use a dick or DB provider that didn't implement the interface, so I want Michael to just blow up or do I want my code to gracefully handle that well, Who am I code to basically handle that. Do you want to call the method, then you can just catch the exception and all the time or do you just say well, I, do the check up front and then I know it's safe and then I've?

A

You know flip some bit and then some other processing happens later and that's usually why you want capability API. So you can, you know, check early if you need to, and you can avoid the exception all together by not calling it because by knowing certain things aren't supported. If you really don't want it takes situation, people are forced to call the api to figure out whether you support something I mean for this case. It's not too bad because you don't have side effects, but it's a pure thing.

A

It gives your data back, but in some other cases is like well, you know right to the stream. Well, I, don't want to write to the stream. I just want to know whether I can write to the stream I'd say: that's why you want to separate it usually, and it's.

D

Just the pattern, if you use to actually make labels that that so the pattern that I can relate to is more to do with systems that you know at a particular point.

D

The system can feel so I check whether the system can handle the request that I am sending it you know or but for her I was just thinking that if it can be done in a different way, instead of exposing function, what I mean this thinking out loud that what happens if I, if I, say that okay get schema, none I, don't have any scheme of you so because, if I, if I don't know the null, then there's a check there and you figure out.

D

Oh it's it's now so I don't have a scheme are to work with. If, if the schema fails, I mean if the schema support query fails, then also there was no schema for you to work with. Well, it's more about the discoverability of the fact that it may.

A

Fair I mean they consider the fact that the question is: how does your co blow up I think that's what it was down to so, let's say you'd return now, arguably, okay, now you have a way to check whether the schema is supported by just checking of the virtual type is now now. If I write code.

D

Oh I mean I like oh it or am.

A

I, like you, had our mothers more.

D

Confusing I mean it doesn't tell you whether it Oh t'adore, not I, was just trying to say it's see that can I get rid of the query method or together, so null is more confusing for sure that was the first thing that came to mind. That is I mean it's about, so sonal is bad for two reasons.

D

One is that it doesn't tell you whether it is supported or not, and if it is supported in is the provider functioning or it doesn't have a schema for you, so, okay, so I want to spend a couple of minutes talking about what this would look like when we go back to da turn a desktop or the full framework that this API.

B

D

What what I recommend what I have written down here is that we take the same method, put it on the base class of DB data reader, so that we can have. We can add this to dotnet code when dotnet core objects that particular frame desktop, which has this interface method, this particular API and in that case, of the an ass targeting dotnet core. If it is recompiled, it will be compiled against the base class, and if it is not recompiled, then all the calls will be routed through the extension method.

D

So if the dll is just dropped onto the new dotnet core, then it it was initially compiled against the extension method. So it's still. The row of the calls are still routed through the extension method, but the extension method is then modified by us to send the calls to the base class. Instead of to this interface, the base class checks that, if it is already an interface implementation, then I call the implementer face method, otherwise I otherwise a call, but anyhow go to the subclass implementation.

A

Person wouldn't even do that I would I mean I would say that if you do our job right, you can leave the TP rhetorics the DVD reader extensions as they are today, because we it.

D

Should be the same yeah, the reason I want to modify them is because I want to put the source of truth in the base class. Instead of keeping them keeping the same logic and the extension we can leave them the same and they they may continue. Actually, no, if a new pipe implements I mean there's not.

A

Much logic in there, but all the other implementations to the AMIA under or against a member. There is logic run. If I make you translate the old move that to the baseline yeah, yes, so by what I would still do is even on full firmer. Today, like the first line, the code should be. Does the read implement this interface, if so dispatch to that method?

A

If you're not translate so in a sense in in the modified version, I would just do the hard costs and dispatch or just directly call the method that either way like you end up with excluding the same code. So yes yeah the way you would do this and yeah and we do what you would do for family will just say: reader and reader door get color schema.

D

Ya know so, coming back to the query, api saw. The granny here doesn't also make its way back into the base classes, or does it stay in the extension and the end of it? Well,.

A

If we move it to the face right there at that point, there is no DVD that doesn't support it, in which case I would not add the method itself to the to the. I would not move the method, every never leave the method and extension method. Yes, just to implementation to say return true, because by the time he added like features like this kimura thing is no longer an optional saying, they're equipped slider has to implement.

A

We always would support a ski mask and the schema- maybe uh you know simpler unless they provided us an extra where you can always provide one okay.

D

So it doesn't need to go back the girls little implemented by everyone huh fair enough.

D

Any any comments on that and you. So we we add a query method to the extension and that's where it stays until they gave moves to the base class that it returns. True for all the implementations.

A

So what happened the course ID on the course ID? We would lead data reader directly implement the interface. We would add a virtual.

D

Method or maybe data readable, 113 implement interface. That will pause a lot of confusion so now, why would you not do that? Oh ok, so I'd kept the method name same so that the base class can take the.

F

D

Id be a column, schema generator.

C

So this is and then this.

A

C

They are bigger, which is that possible? Yes, this is V one ya envy Zhu se debe.

A

Datareader implements I de column scheme or generator. You also add public.

C

C

Get good comes, which major just implements the interface right and.

A

In the default implementation to do something meaningful it based on the conviction that we have and well that means them is like you, even if you don't shame to see the data reader, nothing breaks, but right.

F

Glenny to offer is so now that yeah, okay yeah. If then, next providers need to operate the concurrency on him for.

D

The balls to go to the base classes function.

A

Yeah, what happens to the data to the derived? We said that the right ones today should implement the interface explicitly. So we can add the method to the base in v2 right.

E

The question is, what happens it done by starting prevents a two things? Yeah, that's where the problem is well. I say it doesn't even it's Amy conference. Yes,.

A

That doesn't solve form, because the question is still: if I now write code that called get Colin schema. If the provider does override it do I get me a hater yeah.

D

We can put the people the other, get schema table. Mapping to this data structure there as the base implementation. Basically, what is going to go into the into the extension method for dotnet framework is what can go there in the base implementation so that there is no gap, and so three things do you and do you implement the interface? But the first thing we'll check yes, I do so I will just return whatever they interface. Implementation is so no I don't implement it, and so I return.

D

The DVD, sorry to data table mat to read-only collection and give it back to the consumers. Have.

F

Been correct, X the ternary is.

D

F

This v2, which was have stable s, already, know me or.

D

The I wrong morbot encode this year is correct, for this is the dotnet formal would have to know how.

A

It happened, I guess an honor said. So the way this works is, you would say you would basically have synthesized in fertilization.

A

This way he don't break.

E

The right to fire yeah when you cuss to an interface well, this would call the exercises and.

A

The way I wanna know I'm, saying that the default implementation would would would use the interface as a implementation unless you override it so basically means moving forward. You either override the virtual or you implement the interface. Yes, however, that still breaks consumers that assumed that the way to get the schema information is through the interference only because it means now, if I have a provider that overrides the method, they also have complement the interface. Otherwise other components in the system will not work.

A

So it means, if we add the matter that means for eternity. People have to implement the interface and override the method. Otherwise it's still possible that systems that certain things don't work. Other checks will be done in the extension.

D

Right, the job is, nothing stops them from fine interface.

A

Toric, ah it's amazing. What would have to say is that the only way to get schema information is you should never use the interface. Every interface is purely and communication mechanism between the extensions and the providers and in the next version that communication mechanism just uses the virtual method on the base. Consumers should always call the extension, so the extension can basically say yep and we want to use the interfacing to be to a just called base. How.

D

Do we consume how do the it's just a minute later as a mechanism, instead of and that's why I'd understand.

E

If the base type in the future we're talking about the future, you have evan's interface today directly it implements and it has spiritual death of the thursday implementation of the interface. So I don't see, we have an issue you can. You can cast to the interface. Yes, you cannot contain the virtual implementation that the base type, what I'm saying like the Western Canada from can.

A

Not because the problem is was the default implementation of the add the virtual. In order like the problem that you have is in vichu, you have providers then implemented. If you want. Yes, one of those to work like you want a consistent all right, so that means you're, adding the virtual. So what's my default implementation partial my evil implementation is going to be I I cast myself to the interface. If the cast succeeds or I call that method.

A

If the base already implemented, if I just called keep falling myself, so I can do that, so we should check it, but.

E

I'm pretty sure that I check and I had discussions. What actually happens is the the implementation of the interface in the subtype that was done a long time ago becomes another right of the virtual method of the way. Sir I'm. Not we should. We should verify that, but I think that's. What's have what is happening.

A

Well, no, they! The problem, is you have two things here right? You have the interface method and you have the version, but they have to have the same signature. They have the same. Nobody went into an interface, you specify how you want to let them you can either say I implemented the face explicity, which means the detail. The stuff for the interface is different from that mess. That happens to have the same signature for earth and then his hobby basis tell people to do right, all the derived providers.

A

Let me tell them implemented if it's explicitly, so you don't have a method that is public blah, because if we now add virtual later on, like there's normally, we should check, because I do think that they will have a relationship.

E

And we should disturb people not.

A

E

Promote excellence: okay, I'll tell you why I think that it should all work. I, remember when the very early days when the high system was being designed- and this was very adamant about making things like this work. Basically, you know future editions of obstructions should not kind of effect.

A

Subtypes that made you say any I am, would almost bet a hundred bucks at the work.

B

Nobody, what do you think do you think never I would well I mean I know that the implementer would not be calling base so semantically. It might have different like wait like.

C

What you gonna complain about I.

B

Know that we've promised in the past not to add we've made it a compatibility contract not to add in two places when it changes the semantics, like people get mad when the attic is horrible, because it's a we consider like that. Because of that, so they know how to call base. In this case, it's not quite like the recommendation would not be calling base because there was there was not so for you would, but you would never call Bates right.

A

They sitting, you will always either provide your own implementation or you don't provide it for maybe is moving into the resulting useful I'm. Pretty sure there is disjoint slots, I mean the. If you're on the drive type and to implement an interface, they don't make it a virtual. It doesn't matter. You exist map that represents a virtual slot, but if that, but it doesn't do by the fact that the method itself is virtual, it just is like they just chair one slot, but that's what the interface nap in hecka method later.

A

Does it just last interface method to that.

E

Method, that's all it does. I may be okay. Well, we should offline. Do a bunch of.

D

You know checks, and so the experiments are weeded is that we aren't. We made the base class, implement the interface we made the concrete class and implement the interface.

D

The difference is that if you are implementing the interface directly, then you don't have the override key word in there right and otherwise you are actually getting that API from a virtual which you would override. So if I don't put the override key word and I put a method and I put another method there. Then there was a complaint from the compiler about hiding a method. Yeah.

B

Yeah some of these soil breaking, but if you just slap the override on there, just the il change and I didn't check.

D

Whether I changed not- and the next thing is that yeah, if I don't put though right, then whatever is the interface method that has been implemented. That was being called, though I, provided it up, throw not supported exception in the bay is cuddles rd call. So the behavior that we observe, but.

F

If they threw in a ton a different book, will we bring the interface or we just we just offer either I mean we just helping the fifth 12 when the tribe you don't need to at the interface right, you think you have all done in favor I think we have to decide what.

A

The behavior is the one between producers and consumers in tonic 1v2 like I, don't think we can have it both ways: I, don't you say: providers can either override the virtual or implement the interface and that's transparent to consumers, because they would require that somebody always implements the interface, regardless of all the providers being implemented. I'm.

E

Still confused.

A

The interface would be implemented on the.

E

A

Type this one saying you can't have to act on gusta so because now I imagine you have provider. The provider basically implements the interface, because it's a d-1 provider is here's hold that provider of work the base time already infamous.

E

It if it's initially it's a new slot and then when they recompile it just tells them that the training, a middle layer, I, have a binary finish. Then it's a new slope yeah, but then that pipeline okay. But what does it mean.

A

For the consumer, it.

E

Means well, hopefully, the implementation of the those two methods would be the same at some, but.

A

The deaths will be saying: I, don't think, that's how it works. Whoa. Let's say it doesn't work like that and say that the the public interface implementation of the component has does not overwrite the one that we add later on in the base, which I, don't think is what happens and that's what the cure.

E

A diagram like which methods we are talking about which slots so.

C

E

C

Almost so we have get get skiing on it, that's the same thing, so this is a public virtual.

A

Read-Only collection, BB color, yet.

B

A

This one here is public non-virtual,.

C

C

E

Whatever they at what times uttered 30 min four times, please my throat in this method. This is a single better. We don't get it I.

A

Said this is a mediator here. This is the base, so the problem is if this guy doesn't implement. It is this guy, so this guy doesn't immediately in this case the whole interpretation of the base. What it can do is, it can just say: well, if you are a lead to a v1 provider, while then implement the interface, so I can try to cast the interface with the cast succeeds.

A

I can call interface, which means that the space who just called the derived version of the sky problem is, if this guy walks into this interface in cash, will always succeed and have caught yourself, which is not what you want. Basically, when.

E

I say I would call through the interface, but in which version would the interface be added together with the virtual method, life.

A

E

A

Whenever, okay.

E

So, but which one now he chosen, because if it implements I'm saying if it's implemented at the same time, yes well it better do something more than just casting it to itself and calling itself I mean that's a pretty stupid implementation. We would do a tri cars. Like you say, if the cars you see, whether it's just to try or not it's a stupid implementation, because it's like I'm casting well, it will succeed and then I'm calling the method recursively, which will create infinite, recursion. Okay, nobody would write back so.

A

I'm saying an interface implementation, you can't do that. I'm, saying like the question is: what's the behavior was the limitation of the same so I'm saying? If, if you don't look at the interface, then you can do the try cost, because that has a chance of succeeding. But if you do that, that means that consumers of this tag now have to have different code based on whether the provider provided the scheme of via the interface all the overriding the base.

A

You can't just rely on either mechanism by either call now this guy, which will now work for the two providers. Only all your call so the interface, which means it will work for both old and you've cooked providers, because this guy does the right thing plated it fits into this problem is now. If we, if we do implement the interface, then it will be transparent for the consumer, because the base we learn about a parasite.

E

Then then, there's no way for you to dispatch the director, I I, think I understand that yeah when I was talking about what would work. It is the matching between you know the slots for these methods. They would I think we can make them all matchup in the future. I think it will work. What will not work is how do we implement this visual method in indy? One ring.

F

This other we gonna have to be pranay like I, don't know ha so. The IDB schema has different cat column, schema other things right and then the extension will be the same name, that in the in the digital method, so exchanger interface, virtual metro to swim, learner, so yeah. So the impact, the extension methods with the future virtual method will be the same name, but interface methods will be different, different different name, sir.

F

So in that case, in your future method, you still can can help can have different name right, which is not operating this that interface and you have Caius and then calling the interface methods. So it has different. So it doesn't. What's the.

A

Benefit there, because that still means that the consumer.

F

Has to know which names to use no yeah, no conscience. The benefit is. The interpersonal is only happens in the core FX, but in the.net framework we always use with from methods and alyssa. It might be adding the virtual method in a future for FX. This would work conflict with interface, so in the individual implementation it will be just the same like what is your extension is. So if the providers is implementing interface, they will call the interface, but if not, they will call the off right. So what about this? Instead.

E

Of implementing this virtual method by doing casts and whatnot we thrown that support it exception.

A

And would call this method ever because.

E

Then it basically means the subtypes have to override it to start supporting, and then it would all work and then.

A

Now you're creating a rift between you, wanna meet. You components will not light up.

E

Oh you mean that the implementation, the extension methods.

A

Can never safely call this message than ever because the provider hazards arising that's my concern, like the whole point of the feature, is to say: how can we provide schema information given them? You can add virtual Sudan and fabric today, and it means at all that doesn't matter if it can be too.

A

We can just do the right thing with the virtual and things will just work if we can't do that, I'd rather not do the feature now postpone the feature to the point where we can add a piezo net framework and then do it the right way, rather than to create something that will work for six months and then we add something else that we think is better, but that never believe work safely, because we now have two features. You saying on that that frame of this method will always work correct. Is that what you saying?

A

Well? It has the problem conceptually on both platforms, because it's about what did the v1 provider they could make it with the v1 provider. You use to explore schemer information on full frame rate, we're saying nobody does anything and we have the old scheme information that we can adapt, which is why it works.

A

But I can tell you about a new provider uses the interface I, all users own net framework, and then I have the same problem at hand for dotnet core and if I don't implement the internet, if I don't overwrite the method now well, if you, if you know, call the base mess it, then you can actually give me schema information.

E

All right well, but.

F

What is the problem is? The interface has different name than the extension I mean. The extension will be used by the highest right autumn is not with.

A

The extensions the problem is, like the extensions, are just basically a way for us to do the casting interface and call the method. The problem is between the the provider and the consuming code. That consumes schema information through the base type, because the bottom is so we have to choose either we are saying a consumer will always will never ever call the interface methods directly.

A

It will always call through the extension, in which case we can do the right thing in the extension methods, in which case it's all fine, because now it's okay, fine, we can, we can adapt the right things. You can do the write checks. That's fine! If we say well, the consumer code can always say if the provider implements the interface. That's how I get scheme information I can just call it to face member yeah. Now that means in v2.

A

If we have the virtual method, the provider has to continue to implement this interface to make that work, which is.

B

A

Want but, unfortunately, cannot implement interface on the base, because now we break the light up for the base type to say. Well, if you will be one provider, I can just call through the interface to get schema information. So it's it's that we can only do one of the two like either we make so that'd be one providers will work with the be two of the virtual or we make it so that consumers can always cast to the interface and call the method and have it work and then cannot. You cannot have like.

A

E

Interface, to represent two different concepts.

A

Well, interface, essentially, today is just the basic, the back channel between the basis of the drive time.

F

If the provider doesn't implement interface, how can they call the methods of compartment? The clients will will podcaster in doing the fish right, but it will. But if they implement it you you can call it right. Yeah.

A

But that's exactly the problem because now so that's why I'm saying it depends on what which contract you want to have so if the consume, so let's say it's a bit too provider to be two provider overrides the base. Yeah so can provide scheme. Imagine it doesn't implement the interface, which is what we want. You don't want people to. You have to worry about it to face forever right. That no means, if I have a v1 provider where the virtual didn't exist, they expected to get scheme information to the interface.

A

So to do the try cast the interface. You cannot cast it in the face. It fails, which now means as in consists at the provider, has scheme information, but they can't get access to it because they're the contract has been changed between be 182, but if it is hell.

F

They will directly use the offer at matters right, but.

A

No because it's a v1 consumer, the v1 consumer, didn't had a base tactical ah this way visit. The problem is, if you look at versioning right, you have to be one provider, so I v1 consumer working with a V 1 provider, v2 provider- or you have the other way around right and.

F

You want both to work but p1. We have to use interface fiefdom, you have an option whether you can use interface or you can use the offer at met. That's right! Well,.

A

What do you want, but I mean, like the whole point of the base type is to say long-term. You don't have to need the interface at all, because everything in a deodorant is done by overriding message on the base.

A

That's the model that we want to have that's not the moment we can do today, because we can type a freaking virtual today right so we say: okay, this is a temporary measure until be at the virtual, but the problem is now once we had the virtual, when all you have this rift, because if you use the interfaces you get one behavior if you use that virtually get a different behavior and you never get a world where both just play with each other right.

A

So that's I, think fundamentally the problem, which is why don't like a proposal, because it means that more for non for eternity like if you have it, be to provide them. If you want consumer the other way around, they never really talk nicely. Some of so.

D

This properly locker, if the v1 of the provider, doesn't implement the interface or provide an epi or override the virtual right, because if the base class is casting to the interface and be too if the peace process costing to an interface and checking of the interface has been implemented and then returns line interface implementation. Where is the break there.

A

So he says it again me.

D

Too, we can have two kinds of providers, one who have implemented the interface. Are you three hands provide one were implemented. Their interface second will implement the virtual or override the virtual and third who have not provided the schema at all right. So in that case, in the base class, if each cost, through the interface and return, the interface schema or implementation as the first step followed by a not supported exception, yes order, the right exception.

B

D

Oh, doesn't that work for.

A

Us who does work, it just means that the base that can implement into this, because otherwise you call yourself right, yes, which now.

D

Means that Y is base types, implementation of interface significant. That was the part. I am yes, sir Sir. Okay, let's order balance the base type, doesn't the.

A

Written interface, what now happens is, if you have a good super, yes, then place. It says: I find schema information because I'm in v1 consumer right, my mother is correct. So me one, you say: ok, if you I know that if you implement the interface I can call the pastor to get an answer. That means that code will not work with a v2 provider unless they also implement the interface. Yes,.

D

A

Will not be able to access key right, correct, which I think is unfortunate, because it no means that if you have existing code, thank you basically have to change everybody in the system and in order to really get the virtual in place and have all the components just work. No.

D

I mean if someone is, if Amin, so we so essentially we exposed to methods of exposing the schema. One is why they interface and one is by the virtual, which doesn't implement this implement the interface or one is by I ODB data, which does not implement the interface generally best like. If you have two ways of doing things, the one like what you basically want is.

A

You want to say you know: I want to decouple consumers and producers right, producers can choose to use one or the other doesn't matter in consumers can can interact with those, regardless of all the real tense. That's what you want as soon as you have a coupling where consumers and producers have to change f2, we on the way things are. It causes versioning issues, because if you have it be, one consumer will be to provide all the other way around they're getting consistent answers.

A

There's no man means, if you consider an ecosystem of you, know OMS on the one hand, side and I, you know, like you, basically just move the other way. Then the problem is for us to in order to like make this virtual viable. Thank you start going 4-0 points. Sayo, the design will be somewhat of a virtual ya, know you're saying well, but the ecosystem takes another three iterations to actually pick up an appt everything work. Is it worth it oakwood? We just say it.

A

The only way to do it is by the interface, because then at least everybody knows how to talk to everybody else. You don't have that rift and that's the unfortunate thing, because it no means that whatever design we pick today, it's probably.

E

Going to be designed, we have two different well, so that's what I was saying. I think we tried to represent two different concepts with one interface. One way we could do, it is just have imagined. Initially, we should interface with method, get schema core, you know and then in the in the future we had the virtual method called cut. Schema that get schema core is like a provider interface. Then schema is I, I natively support, schemas I, don't need to provide it and then then it will all work and.

A

Don't you understand what that proposal would change I think what you're saying is that you are basically by name implying that consumers should never get schema information to the interface devices of the mail and it will keep working if.

E

I were to keep looking that's the thing I don't understand, because if you implement the interface you provide schema, so why would it not work point? Is that if I expect providers.

A

To give me the schema, why are the interface if the provider does intimate interface doesn't mean it doesn't have schemer, or does it mean a caller on line if.

E

The provider does not implement the interface it it. It.

A

Means it may provide schema, lies some other mechanism, it doesn't mean it doesn't hurt. Yes, that's the rift I'm trying to fix because it means in v2, not my modest ultimate interface, there's a whole point.

A

If we could get the base captain's with interface, and the last thing is the provided along, it has to implement interface because the base of our satisfied said, but that will make it impossible for the base up to light up on the presence of the interface in the drive time.

E

But so then there's this virtual method. If you override it, you basically.

E

Deciding whether you support the schema information or not, because you're changing the default behavior, which does the cast and now it you don't even have to do the cast to the interface with just implement and provide a schema I think it would. Maybe it wouldn't be ideal, but I think it's.

A

Pissing on shares and telling what you're saying because I mean it seems to me like we're just tiptoeing around the subject of what we break so look. This is.

E

It should be complete, I, don't think we bring anything so the virtual method or breaking a.

C

Hard for mary todd lincoln since.

E

It has the cast so far x equals this as I. What would the.

B

E

First and that's what so dancing the bedside now I'm a sound right and I. This is my subtype. Yes, I implemented this interface and I implemented it's in my power. That's a different name is designed explicitly correct, I it I explicitly domestic now I recombine to a new version of this based on and I know that this, which I meant what I just override it well I kind of will keep both of them. Consistent I will make sure that the repeater is to say that one.

B

A

E

Don't have any power to this. So what? What is the problem? The.

A

Problem is this party over here the.

F

Consumer yep is in with a BB data reader. Is it end up, call the consumer it for the call or I mean for real FM books. They will only have the future. They won't have the interface refugees of the problems, but it's problem only part of LA. So basically I guess that's a fair point like let's.

A

Talk about the keys to pay the consumer based on court, because you're calmer get on MV one every what Evelyn spectators? Yes,.

C

A

Have to convert into this if I make that assumption in my arm upper deck cast to the IDB of a bun and I do whatever magic I do with the schema information? Now, let's say I'm mp2 provider right and I want to override the message to get rid of the interface as soon.

C

As I do that you don't live.

A

With that's extending my point, so that means for eternity. If I want to write a provider that works with the ecosystem, I have to override the virtual and provide the interface in which point I would say why adding the virtual in the first place. Let's look for Duncan say it's only worth it if it's much much simpler world, but the conch always have to do both anyway, then this is f1.

F

A

F

It has iron, ideally they should go to the expansions or to the offer me that they cannot just that's a better Malik position.

A

To have you can say, like consumers should never ever do the cast, because it will not work in full time break anyway. That's a good this case you would say this is always consumer and that's a fair argument. I'm just saying it's unfortunate because it means it like what it totally matters. How you want code consumed schema information if they do it. Where are the extensions then, in p2 you can literally drop the interface override the guy jumping interface is a breakage.

A

Nobody should be so fair enough, but like let's say what you write: a new provider, it's starting provider from scratch, and you want an existing or my fur to work with that guy. It's the same situation to implement the interface and override the work. So do you just provide the the override I think the world we want to have? Is that long-term? Nobody ever has to do in this interface.

A

Ever they just have to override the virtual, because it's the nice thing about having a virtual and would say if you have to do both realistically, then you know I would not add the virtual at all just say yep. The way you provide ems reprimand interface um but I. Think if you say well, consumers should never call the interface directly. They never think it's fair to say. Well, you never write this going rate. You just call get cullen schema and that guy will do the right thing and you want able to adjust.

A

Do the try cast and if you would say well, I just call this guy and then that's the end of it and I will need to sit in.

E

Front of the cure really good, we do reach more.

D

This is I mean, ultimately, will break someone for art or the other, even if he comes by a message, a yeah well.

E

We're not gonna be. We cannot break anybody and I. Think if the moment you implement the interface on that provider, you will have to keep implementing it now. Emma pointed out what it means is that some future providers will be kind of forced to follow this pattern, despite the fact that they don't have to then I wouldn't say that anybody.

D

Would be broken are not contesting that heart. What I'm saying is that if we say that okay interfaces the only way to go and or if you say that no, this extension method is the way to go to access the schema, but there's no mechanism to prevent anyone from accessing this, keep my using the interface and here I'm, not mr., so.

A

It just means that if you are in we're breaking is wrong word. Basically, what it means is, if you write an army / or if you write a provider like you have to be able to say well, if I want everything to work, I probably have to do both is the old way and new way and I think that's unfortunate.

A

I'd rather have a world where it doesn't matter how all the consumer does it doesn't matter how the producers is if the bruiser, this is the old way and then Sumer the new, where the other way around they've always be able to talk to each other uh and I, don't think we can get to that wall, because it's well because the the channel differs at some point. You know you know you know you're able to dispatch across these boundaries. Well,.

E

No, we still have the option of a DB provider. The base type never implements the interface yeah, but then what I'm.

A

Saying is that you can never rely on the fact that interface is the only way to get access to the schema information, because if the provider doesn't them in the interface and over at the base, you don't get access to the schema information, in which case it matter that you asked for other people mechanism, although I 32 mechanism and that'sthat's the roofs that I'm trying to point out.

A

Because you can't have it both ways and I think I mean that's a mean thing. It's a fair design. Point just means that something or designers as clean as we originally thought it would be, but it doesn't mean.

F

Every should do it, but what is the reason consumer consuming I mean podcasted fights up like what is because that's how people yeah, I guess, the because the interfaces just have one matters right, which is called car, and then we shouldn't, we can put a comment. Iono should call them get column scheme under which did properly pants and.

A

Then I caption yeah, it's the same of other cases. Right I mean if you develop, miss you at the interface. An interface looks like what you what you want like and the question is: do people understand this is just for the providers I mean you can do certain things like falling into different names. For is nothing we have one, but you can put documentation on it and say this is for the provider.

A

Don't do that use the extension with it over here, but they give all things that people don't read dogs and if they they just coat coat things up. They tested at the code, works they ship it and then the resulting the dogs. Don't do it this way, like you know, visual honestly,.

E

You know there won't. There won't be that many people can implement the providers. I given that you know the complexities that we just discussed. I was just not at the virtual. I would just teach the provider. Vendors interface is the way to get to see much because at least it's clean. They need to know to do it. It's not, as you know, Selena philtrum methods show up in intelligence and whenever you type / eyes, but at least it's very clean like once. You know that you have to implemented. Interface is very clean.

E

You cannot make a mistake, give when we add, like virtuals and the interface there's a potential of calling something incorrectly and a lot.

D

Of confusion there are Mustafa read so what happens in v-necks soapy just take the interface and put it in the framework and okay and the access. The extension method doesn't make it to the framework, though right the are.

E

At the moment, the interface is there, it.

B

Could but then you couldn't, then if this came along again you have a new type.

D

A

Don't think we would put the extension method. Yeah we'll put the interface in the firmer. Yes, they can change. Anyways and I mean they. You know that allows providers to do the same thing there. They can decide to go the old schema rod. Well, they can't go with a new schema route and yes within the family, that will create a rift, but hopefully more people share could go between four and fabric, which case it doesn't matter and then so.

D

Slightly different question so I understand that we support ECL, but what about code violation whole compatibility between core and frame book, I assume that that mean never be possible right, because there will always be something I, hadn't over or ahead. Remember, compare I mean we are striving for the. What is being able to write health advance of both sides of the same binary. Yes same minded, so binary compatibility is what we're talking ISM force upset. I was wondering that.

D

Do we talk about code compatibility as well, that was just with the source for compatibility, especially with respect to this exchange, and this.

B

Will not compile.

D

Or portrait framework, even if we put the interface and not have the extension, so want to know what 13 it there is so code. What the idea is that, if you, if you keep buying a company.

A

But it even though they're strictly speaking, orthogonal, then final combat is more like a stronger version. So if you bind your compatibility, you're.

B

Obviously, most cases source compatible to, I think you're talking about source compat if they didn't have the package that included this extension. Yes yeah. So that's.

E

You have to have the right packages yeah, but with the moment you have the right packages, then it should be sauce or do.

A

So it's really volatile a system. Everything is great base. If you don't have the right references, you if you saw some not compile and.

D

So I guess we need to go back and think about our little bit more then we discovered more problems with the initial discussions that we are here in this meeting.

F

So so, if we want to bring the virtual center in that, this doesn't need to be a different name or we just put it differently: Lucas, oh the same interface, I mean and I'm in the interface name here and this moment, because we considering bringing the filter all that's why it has to be different name at schema corridor.

B

Should I mean.

F

The interface name, the interface methods, all get schema Korra feels different than what is our extension. You know, but if we decided already that we don't want to bring the control method in the feature, then basically, this interface name can have the same name with extension in.

E

The metal, thingy resonator.

F

E

Yeah yeah, the core would always would solve one problem, but it introduces another. It solves the problem that you know you can. You can cast in this virtual method to this interface and call this method without worrying that now somebody implements you know another interface that has a method with the same name, and now it's infinite. Recursion basically have two different methods correct, so they you don't create infinite because it introduces the problem. The team are pointed out that now you kind of have to implement two different methods they have to be.

E

You have to be very careful. They have to have the same semantics otherwise, and we have three races and.

A

Make lots of mistakes? It is.

D

I would honestly say that extension, whether published should mesh interface method, I I I would like to go with art so that at least we know that they're doing the.

A

Same thing, because I mean in MV one of the neck or whatever the version of recipe we we basically would not add the interface to seek with a decline in the contract, which means, if you're an Intel, is sense of the data video. You will only see the extension method you.

F

A

If your env to where we actually added botnet framework and the other side, while you see that in intellisense it will basically replace quote-unquote override, essentially the the resolution, the compiler will see the extension at the end, the interface on the specific type. If you, if you actually have a secret data reader- and you can call that method, you will now call directly all right, I passing the extension method. His verse k, it's just by system, / of which wouldn't be bad.

A

If your DB data reader, you will not see the method at all, so you only see the extension method, in which case that thing, that's the bad thing, so I, don't think. There's any problem and I think it just creates clean, intelligent experience, because there's only ever one method to talk about and see they're an extension method or directly on the time.

A

All right, so that means no virtual way to.

B

D

Will continue nobody's last modification at all one interface, one extension, one.

A

Extension 18 yeah.

A

Frankly, if you will get default, implementations of interfaces, I think you would have a very better way of doing a burgeoning, well and also I just was.

E

B

A duck typing my rent, yeah, maybe maybe maybe default in your faces. This is simpler than that.

E

By the way, we also just invented an idiom I think for.

B

How to do virtual extension methods? Yes, I mentioned that you know last week that we need to start come. We need to have like a recipe book of here, though here are. The patterns were establishing 22 group desktop yeah when.

E

B

Want to add this type.

E

Of thing, though, we should result, accession metals are great, but they you cannot make them virtual. Where you can get an extension methods in sightings extension method to cuss to an interface, then you call whatever you will treat. The default implementation is to tell cast, fails yeah, and then you provide an interface that is your virtual accreditation, yep and.

A

I to say, but that sounds like calm managed to come and left come mow mow, calm whatever you want to call it. Modern calm, I think I'm already taken.

A

Yes, this is how I get trouble um anyway, so I think the overall. It guys look good. It was the only contentious point. We had right anything else that you wanted to cover. No, we were just a little wise. I think what.

D

A

D

A

Is the only other thing that came to my mind was should be create? Actually a compound type of that? Do you think we'd only collection of DB column will satisfy you for eternity, so.

D

Those won't be returning today Beatrice what we've been doing since a long time, so this.

A

Should young thing you ever need something else like meta information for the egg, for example, what happens for cases where you have a curie that has multiple result sets it will find only a list from DB columns. So when I'll do, I know which columns belong to which result set? Would you say you call the method after you move through the first result set another.

D

Collins that you would return is the second yeah. It's basically on the state of the reader, the data reader, whatever it's like a point or wherever it is pointing you're supposed to return the.

C

Mets into me, I think, that's pretty much. All we had cool.

A

Yeah I will write this up.

D

Again, as you get I will will go back and think more about her in case B. You see that I mean we have simplified it over spider and gone back to the pair honestly.

A

I, like that model, more cuz, it's simpler, it's less magic, no, not necessarily as elegant as a good people.

A

There is no confusion this, it's very easy to reason about what happens between the one b2 and b3 and b4.

C

Awesome nobody.

A

Online at any questions, I guess that either means it was too complicated to follow, or we did a good job.

D

Anything else otherwise, so what do we do? Do we change after changing proposal? Do we come back again or just change? I mean I. Understand that the onus is on the owners, wishes us I guess so. I would honest. I will just write up the notes. I will send you the notes. Yeah.

A

And then what I would choose I would, just if ever you were just edited the whole issue, yeah strip it down to what it is now and said. This is what we discussed. Okay, then you know that's. So it's more like an FYI for both of us to be on the same page, I, don't think, there's any like major reasons I was showing. I wouldn't keep you all over on, for instance, don't think we'll go back in time and say: let's leave the original proposal again, they've enough notes.

C

Forget it, let's dance you, alright, thanks.