.Net Foundation Design Reviews, 4 Aug 2015

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From YouTube: .NET Core Design Reviews: IO and ILDASM

Description

Agenda for this review:
- Discussion on resolving behavior differences in System.IO across .NET FX/.NET Core as well as across operating systems
- ILDASM demo

A

A

So today we'll talk about two different parts: the first part we will talk about behavioral differences, that we have an Ohio stack and how we will deal with that across da Americans on a core as well as operating systems and in the second half we will have a demo for the work that has been done to a manatee right off, Miles dozen. So I guess you should probably get started, just walk us through the differences and proposing what we should do there. Alright.

B

Well, I've got five issues. um Two sets of them are fairly similar like this. One here has to do with access time, right time, creation, time or directory and file or directory and directory info, and the violent violent, though essentially on windows right now, the desktop and with the score. Whenever you try to get one of these attributes from file that doesn't exist, it'll return from file x, 0 0, so it doesn't throw exception. Anything like that and then on the unix core. We have a throwing exception.

B

So the question is: should we keep this behavior, that's already there, where it returns, essentially invalid data, or should we have it throw an exception and make it a breaking.

A

Change that makes sense.

C

So what was the rationale for returning zero? Is it because the was it like an existence, checking where we didn't want to disclose that the file didn't exist for some? What area.

B

Back in the day or I suppose so I did find in the comment anywhere saying why there was this behavior.

C

Cuz, I will do least we treat file not found. We would collect non-existent piles like empty file, so people couldn't accept.

D

If you return 0, it's quite easy to tell a bogus data hanging.

C

D

For the person exists.

C

Does the documentation mention anything about this? I.

B

Did not find anything looking through me.

A

C

Yeah, no, yes, I'm still thick tree.

C

Was the first in the shoulders that PR three I.

A

What was a present yeah directory.

A

And what method was that get access time or was it radiation? Tell ya.

C

Does the right things we already returnable the 22 path does not exist. If you look at your marks, the second group director described does not exist. Some of the returns midnight.

A

Interesting so.

C

You're kind of did document this I.

A

Mean is a gentleman principal I. Think I mean unless there's good reasons that would deviate from whole family would just make sure we have the same behavior um and seems you still have that home windows right. mhm So this.

B

Is my music so that those inception yeah.

C

We make it not throw dirt yeah. We.

B

Just how to do the same thing here this.

C

Is easier to change the.

B

C

Being with them, since you can already have this documented behavior already.

D

Are we go to consider just throwing all kids it's? What is helping code zero? They.

A

Did will be very hard if you write life? Is it run on ball right, I mean the question is how much code relies on that behavior? I did that's hard to tell, but.

C

I think people wouldn't expect to throw an exception of the path notes found now they'll be getting an exception, so they wouldn't have had a try-catch around that, usually because you would never. This would throw in those kids.

A

It's true, but I mean chances are if the file directory doesn't exist and it doesn't throw that their code is broken, they'd be called them even knowing it split only surprised if any of you would not even handle the case that it returns midnight. We just continue to whatever then go.

C

Yes, but again they continue right, so they have soon. No, it is.

A

A breaking change for sure the question it's just like is the code already broken or not, because chances are like know, you have your just broken in a different way. Now you just get in it exception. Where previously, you did well.

C

Yeah, but you could have handled that case without the triquetral thing and you could just throw check the 820.

A

Mode argument you cannot drive exact color, correct code. I'm saying is, the question is how many apps in the wall actually did handle that case of.

C

A

And not just take this output and then feed it in the computation into something bogus for that and it's hard to tell by just about actually looking at you laughs um sitting. There doesn't help with that and.

D

If you write, the portable library still can crouch exception and also, and then also have a check for these conditions, Qiu Yu Gi.

A

It so you can store a follicle colleges, you have to that. You become super Potter, but.

C

Everything if we were to change the behave like I, think that that we should decide on what the correct papers is. It is it is this or is it throwing exception?

C

If we think the very inception is the right thing, then keep the behavior and Windows and Linux change the winners, behavior and then start moving like like bring that change back to the desktop under a cork, so that the platform moves to a consistent state like we can't end up in a place where, on some platforms we throw on some platforms, we return 0 and go well. You can just like write this convoluted thing that will let you paper over the differences like okay,.

D

But, and also like when, if we decide that throwing would be economic behavior, we are some kind of need to decide how bad is the current Decatur like is.

E

It worth fixing.

D

But it might be because the kid they couldn't behavior unless we are missing some good reason- is so lacking, but.

A

It seems to me the high order bits wrote a quorum inconsistency between nine clinics and windows unless there's reasons to deviate. I think example would be consistency with desktop if possible.

D

But then you have an then you have two competing rods. We all agree with the main Bob. The first wonder she said, which is consistency between. Of course, you are between the support, dude OSS, yes, and then you have two competing notes: correct, behavior and consistency with disco. Now.

B

D

C

Without even in sacred memory said the same behavior for doing windows and mac right, so we can have this behavior between Windows and Mac, no problem, video in Windows and Linux a problem. Now we may say that that, like they designed in a vacuum, that was the wrong behavior, which it does others day, but it's very easy to align the behavior that if we want to move everything forward, you can we.

E

Do that seven.

C

Yes and it loosens like the changing it to throw a linux as those more technical choice, so we would get parity right away and then we can decide if it chooses two exceptions. I would also argue that I mean it's.

A

Pretty I don't know how common is a TI alcohol, but I would also argue that if the baby would be massively wrong, we probably would have heard by now that people don't like the current behavior. It's probably not too bad yeah.

B

A lot of these these bugs that I filed are pretty just in edge cases that I can find homes anything about. Look I didn't see a lot of people complaining about them from.

E

B

More so not really.

E

B

A

Yep the second one was a line.

A

Is there any so in order to make a decision like? Is there any strong preference one way or the other whether we basically make everything forward fix desktop or we go with the technical choice and just end the case.

E

A

We tried the same way as to threaten forever I.

A

Have to argue that, for my point of view, I, as I said I think, if flowing, would be way more desirable, probably won't.

C

People would have complained about that case. Only anchor is a tactical 60 simply because of what I don't mean to make. It will change everywhere. I.

D

Still kind of who do I I suspect, there's some reason for it. I mean it. This behavior is so weird that didn't happen by accident. You make it.

A

So I subscribe to based on past experience,.

C

Anyone's even document it I.

D

C

Made I have no history about this, but I think this paper meet because like trying to wave the exceptions, I mean it was like you know. If you have a lot of files and trying to get that, he knows a date for it or the time axis, and they will get some exceptions through to be very bad. So maybe we just we were trying to avoid Josh. Yes, next section.

C

Is it big in many similar cases who throw exceptions you're right but yeah, and it's not like the sepia doesn't throw like they really have other like it throws five six five different exception, so.

D

What is it? Oh, can you look at the implementation like what does win32 API do if I was returned.

C

Your code, like you, it just.

A

It's actually possible the way. Win32 returns you because.

D

If a exactly, if win32 API just 10 0, then.

B

The league in s.

A

The reason for the here, so we didn't even handle the case. It's like happened to her like that right here. She actually I pretty sure. That's exam I.

A

Mean you owned oil, you know what so.

E

The advice yeah.

A

Wyd return, 0.

E

C

It's your shoe doesn't scroll anyway, no.

E

I, don't probably marry.

C

D

Yeah, can you actually like quickly.

A

How does anybody know the underlying victory to a PM, 10.

E

Miles you canna now all right. What does it say? This takes three optional of the all-time countries that are and then, if L value is zero, it yeah see.

A

E

I mean that's the reasons it's like. We would have to fight them, but window. Usually we are given day to era, translate into something useful, but.

D

The defense bull, what.

E

D

What does the boat meet success.

E

C

D

C

E

Are we? Are we actually calling get file time or are we calling by next five pilots.

C

Tributon for life I, don't.

E

Think we call use like that leave it.

A

Fiddle didn't know something differently.

C

E

C

E

This entire garage, we changed a bunch of this for pleasant.

D

So it functions exceeds bodies under stairs all things possible that like, if it fails, we don't know whether the five then I exists or something else. So we didn't know who I.

E

D

E

You give me on look through the history of this. Of that card, I mean you just.

C

Say return to full vote from backward compatibility. We.

E

Should probably try and clear that up right now so.

D

Another option we could do is just implement the existing behavior, just God will be like the way we would like the framework to behave. It's different, then how it does behave and then, once we kind of know the killer bankers of many of these, we decided what to do with them, because, like doing cooking and changing these things, one by one I, don't know, maybe it doesn't have enough value but like doing them in bulk and basically saying we fixed a category of issues and now throw exceptions for things instead of protecting public values.

E

That made and I've already done this for 15 years like. Why did we change.

D

This by because we're now crap for well when I'm doing it, we have now currently different hitter on it, except like as we unify that so I all why we are doing this guy thinking. Maybe we should look, should we do what what was nice.

E

Yeah, we should probably meet integer right.

D

Right sorry I'm, I can let say, but do is visit returning bogus day, does go whether we should throw an exceptional. We should try or something it's a separate issue, but like today that the API just returned for the state by Fergus data plus.

B

The other than I can.

E

Donna that I can buy key data that I can't record as Fergus or you can't resume the new.

C

E

That's not party Scarlett as well, so maybe if I was created.

D

E

Really, like very tiny night time right now, daytime Ripper I'll be retaining it right to nighttime represent. If is it actually daytime min value, or is it actually the lowest value that, with a two can represent that the win32 fastest.

C

You might think this is nineteen.

E

Sixty something.

C

Which is the most better product, I get serious, I, giving more 1960 and say say they said it's the same as from file. Kinda 0, just I.

E

Care about it, so it's not that it's not that do you have soup.

E

A

You have to go to a time.

E

That file time from file time, 0, okay,.

A

I get paid I, get kind of great criminal intimidation does find first file and then cause API is to actually put in the attribute data. So it doesn't actually call that particular API yeah.

E

So and I knew that reported I used to, but yeah I think we actually call this particular aight guys I don't know, get.

A

E

All right, yeah.

A

I mean obviously attribute data, then they slip it in.

E

A

E

To it, but in the in the fine case we want to we don't wanna walk up against. That's. Why wait yeah I mean.

A

E

Change for our full.

A

50 for Debbie look at the code is great, maybe an older than ends right. So then, so it seems like it references. We just keep the Famer behavior and makes consistent across my canned goods, but.

D

Could we could we keep the background of these issues somewhere in to walk with that, because I bulk- and we say- let's just you- know- fix the washing here in Cana facts and then talking Walt forgot that we would at least remember.

C

That you can tag the issues, our github, some type of need to be everybody.

A

End I would say based on past experience, we never do. We never I've.

E

Never had complained that they said. Yes, we are seeing me Alex not been honored. I I, see we get saying bit.

D

Tigers, you know won't hurt it's not like thornwood me. I would not make that. You know, like the attack that says, to revisit like public promises, ya author I mean to say you know this game. If you don't like it was the condition says that some file system and a Quonset file, prime, so 30 APR x 0.

D

Could you throw such I think you're? Turning here faulty you don't.

C

D

Why 12 within my name is that's fine, it could be, I will just throw exception, say they fail, but.

C

There's a really nice ever a time you.

D

Could enjoy a treat now.

C

If there are any exceptions that tell you something like path too long or a valid pass, but so it looks like this I'll can't be found, but, as you said, there might be just not affect.

D

Doesn't exist, every show rap.

C

D

Don't give excuses, I whine about reasons if.

C

Not I really the defaulting. It's.

C

E

Tight tight yeah, you.

C

Know used a time, we just use zero and then it becomes whatever they do.

E

Represent spit in zero in terms of quinte, two or zero in terms of whatever the file system is on every particular IRS, but.

D

Hopefully they time 0 was the same day. Yeah then from.

E

1970 sure sure that's.

D

My point: don't want you to say new daytime 0 I'm gonna get two different dates. No, it's how I seems like this.

C

D

Like a way, I thought I was just ask a bird like if I create new daytime and pass 0 yeah.

F

I will get the minimum date, which is general Ferris.

D

Are you doing that yeah exactly okay, but.

E

D

We're returning the military policies.

E

E

C

Right I think you want.

E

That climbed up profile time from files I'm, is that going to always be with 82 concept, or is that? Are we going to translate that for Winnington.

B

Right so right now it's hard coded. Ask you to that. Yeah.

C

I mean the documentation says that we do from file time 0 right so like it seems to me that if the goal is to have the same behavior between windows and unix windows in math, we would do from file time. 0 got kicks just like. We said the documentation.

E

Like we wouldn't try to occupy about what foul line from foul time, pretend what what's the, what value would 0 beep the part.

F

About two years hope exhibited the same on units as proposed.

C

Metc- and I would assume that to be the same right for UTC, wouldn't be the same one. Every person both.

E

02 with a to make something different to mac and wait. Yes,.

C

But we're using zero as like the value, the universal time right, wouldn't that be the same across iphones, no, no from file size nor us, but here I start a different time. So I did question his face. Is his I? Getting the question? Is her gate, I'm from file time? Do you assume the streams, the wheel 30 to file time concept, which is like a tick shout from a certain epic? Yes exactly, and I would say that by default, my guess would be that we would not change the meaning of that.

C

E

Would say the file.

C

Time, epic is a witchery to concept like.

E

Let's, stick with that and then tofu to come up with the file system with mean zero in mente. Two terms has actually real meaning and it tight it with that problem right. There.

B

Easy file time in general, a win32 concept, your.

E

A

Just I, muted, Steven, so I think I just yeah.

D

Genève, that was very loud.

C

Sorry Sorry, yes, even it is a win32 concept, so I mean this is sort of. My point is like it seems weird to go. Change the meaning of, like I, think yeah I think we.

B

Just accept the back and it's a win32 concept and we've it Abuelita yeah.

C

Okay, I mean it'd, be interesting to see what we did for her silver lining. I, don't remember off.

E

The top of my head- oh so well, I, probably hit a lot of my stuff from go, did I, say: well, you probably get it thrice s4.

D

So can somebody terrify that we are actually bringing the same value because.

E

D

Are kind of you know trying to get the consistency between the arises, but if we are returning a different value, then we are back to my I.

E

C

Write a test case right, I assume.

D

There's a test that.

C

Fails today is like everybody who discovered this right.

D

D

I fix it, but I as I said. My opinion is, if we fix it, we should probably a big smelly of these in bulk, not just one I think it'd.

E

Be very hard reason that this in a quick way right, you imagine code base, it's moved from 10 to 20 to 35 4 and then in some update. We change this to throw it down and they recompile and now every single access to get right time get creation. Time now has to be wrapped in a try.

E

That would be very hot record like to measure the codebase like the estimate should have to look at every single use you suck it yep.

C

E

Is right? Yes, I did.

A

A pull up for that, let you feel like I, don't even know what I would do there, but if you ever did, it seems like him. Could hug.

E

A

You're, taking actually thinks that support, there's any more questions on that. One I think you've got all these little chloride. This.

C

Video shoot them yes, I'm, so.

C

A

B

E

A

A

You just leave it open and then what is this? One isn't the same thing, except with file: that's IC, so they all like physically this one again same thing: no, no.

B

One's different, so this one has to do with the create sub directory and directory info parsing its input completely differently than all the other great directory and create files. And this one.

E

Is you give it just about.

B

Sorry, this one isn't about cross-platform. This is just in consistency within the windows. Implementation right, um I really think it's in the lytic 12. No, no, but I meant like it's not a difference between Windows and Linux. It's euphonic.

A

Yeah Yeah right.

B

So if you try to create a subdirectory with just white space, it will return the parent directory. So in this case, will return parent dear, whereas, whereas if you tried to make a new directory it'll throw an exception with just white space, well I'm from a perspective, it actually is it different from linux, because we don't, we don't trim out the white space on the on linux. Did it.

A

D

A

The same behavior as you described here right so.

E

A

E

Your this kind of something that you guys should just go offline and try to figure out fight, go and come up in the proposal. Jeremy like this is no really an fx DC decision or, but why.

B

E

The same I hate urine, thank you quote. Sorry.

B

I'm in lieutenant, this is a case where there to framework AP is that are logically the same thing, but are behaving differently.

C

That the CBP editor has different things like we just handle white space, and you know other ex new line and have is different like a dude and see like it's. The same API has different behaviors based on input. Right is that that.

B

One like we just are so yeah I was, I was actually I thought we were looking at a different issue yeah. This is very similar to the next one, which is what I was actually talking about. Oh, but.

C

In this case to just treat white space like spaces differently than a new line and pals right, oh no.

B

This one has to do with how um if I give you example, there.

A

This isn't fancy ice.

C

A

C

That's what it looks like because it's not white.

A

Space is literally just character, 32. Whatever there's speech.

B

So the problem was that directory create directory will treat white space differently than directory create subdirectory. So if you were calling directory create directory with just wide space on Windows, it would throw an exception. But if you do the same thing with directory info create subdirectory will not throw an exception and overturn parent dear yeah.

B

C

D

C

It's not creating a something it's just returning. This.

E

One, what if I, do directory create directory, see Tim seatback, slashed and backslash spice, because that's equal one right, yep.

B

Yes, so all created subdirectory does is do that, because director create directory.

E

If we called Jerry got create directory, see back / 10 excise space, what what what happened.

E

Because that would be the equivalent create.

A

Subject, thank you argue, that's exactly what this thing does right. Yes, yes, so.

E

B

E

Consistency existence.

B

Is if you just pass a like a relative path of spaces, it'll throw an exception. The past few visits with directory create directory, but not directory it up.

E

Create sub by kesha creating a directory, it's just faces would imply we'd, go and I look up current directory and the spices and, and the current directory, assuming it is the same, is great subject. Yes, okay, let me throw out that.

B

There's another issue which is the next one that it's pretty related to this and that one has a better example.

C

D

In that case, there.

C

Is like the description is between two different API is correct. The other handle whitespace a book. What are those two consistent within themselves like create subdirectory behaves exactly the same across platforms like create directory, because there's just a question of who want to have the same behavior within create directory and create subdirectory know that.

E

They're not the same import. The two different quite the same input would be C colon, backslash 10 backslash space and create subdirectory space. That would be the same in place till you're just placing space to create directory. We first have to figure out what the root is.

E

So then we we going I like we're going to grab the current director an end to that and then I'm guessing that we validate some some white space check there. Well, if.

B

You just pass space to create directory or throw an exception.

E

Yeah but the the inputs are not saying one is creating a subdirectory given this route and create directory, saying create this directory right here. Do this directory the scrubbing parent directory of its yeah? Well,.

B

The test that I made that copy that Thun this particular instance had to do with trying to create a subdirectory in single returned was so does it make sense for a parent directory to do dot, create subdirectory some white space and have it just return.

A

B

Instance of parent directory.

A

You argue that this issue is basically the difference between an implied root and an explicit rule.

E

E

Are you sure yeah I mean if you write the code, I mean that's? Why for another number, if PA would catch it, but so we could just.

E

B

Won that it can.

E

A

So you're saying, oh my god. After what did you say, create directory I saw a directory, even all right guys create, and then you say: d-backs our prayer team.

E

Backslash spice: what is that? What does a virgin I'm.

A

B

E

A

B

This way, if you do the instance of directory info, that our names on.

E

That second, one is I, get me to character, I, Korea and spice to it and create it.

C

So if you, if you look on directories temp, what would they do with the hell? The same in behavior, not.

E

Will be saying that it which are just because we come back, we're clearly validating.

C

Yep, it's actually worse than nothing tells you that I created your parents.

E

But this is the only this is win32 it like going. You go and create goodies and Dawson. You say that so the same baby, please kind of signed by yeah.

D

We pass an existing directory to these api's. Do both of them jump in turn the directory, they don't create anything, don't throw an exception. Just.

A

Yeah I know that's the production. You have to go and sell us weed. Behaviors.

E

Just directory dis we are, are we on I, say just resent it.

B

Unless southern it over to.

C

The same thing as.

A

B

E

A

Glad we do cruzeiro their equivalent.

E

Is different than five is: give me the current directory pinge? Hopefully all the right guys. It thinks give me a count directory event sites. I give you would think that I think you've begun to pass such get full pass on an empty string. Just like that, the same you get it would throw in. So it's not just create directory here. I think it I think it's pretty much every single IP I to be it takes a pop. It does validation. House combined does not do any validation, so the windows naming conventions say don't end.

E

The phyllo dough came at the space your period. The final length also miss supportive, but chillin such user interfaces. Don't so one of you for doing some validations say: oh yeah, we re and we were fine with 32- is refined, processed right.

A

But I'm guessing that's what happened so for number seven. Basically, you all basically do nothing, correct, yeah! That's what not exactly so basic but I would argue. This is budgeted.

E

For than five it is, but so this is more than direct directory got create. This is every single pot like get full path. Also have the.

A

Same time sure I mean the Krishna's additionally. Does that part of do for reasoning about that, but I mean.

E

The other question I think: maybe the question is: can we treat spices as a relative with that, as we've thrown spices when they don't have a route? That's the.

C

So it looks like normalizing the past. The first thing we do is give I growth right space at the end. Yes, which is why that one goes of us a like, maybe give it.

E

Would give you what, if we put a backslash in like spice, backsplash or whatever, like is.

C

That it, the princess, is like cream and I.

E

Wonder in number five what happened to be out backslash at the Israel I'm five. Sorry, oh yeah, like what do we doing that any one of these baby is a heritage. I'll come true tonight.

B

E

B

Trailing News News fit or a trailing whitespace, so I think that probably throw out of the trail for.

E

The trip it will drive leave it five hours. There's.

B

That /, there think it's know why you just only trim the trailing whitespace characters. But if there's a slash this- and it's no longer trailing to decide that slap, that means yeah.

E

And that was a nightly rate like that yeah I. Don't.

B

I, don't think about throwing I, think you're gonna get a directory for your route, I think you're gonna get 14 c colon I.

E

A because it's Rudy and you ride it. It.

B

Also, nine will originally then we'll throw if you pass a new line, character, tab instead of space. So we did new directory of you attempt to create subdirectory just of a new line and that'll throw I.

C

A

In order, I could not it if.

C

You see like yeah.

E

Look second line long Steve well, yeah.

C

This is great, hey.

E

C

D

Like here like the here may not be intuitive, maybe we're designing from scratch that it reflects it. But it's dition that the first you should discuss, because you can just do the same thing on linux and mac and there are no there's. No working is like in the first example where yeah we could do the same thing on linux and months, but then the final times a lot of the same concepts, and this one is just you discovered something that is a bit strange. Yeah.

B

Well, this is, this is already sort of not relevant to linux and mac, because spaces and entire white space names are perfectly valid file names.

B

So we don't do any of that trimming.

A

The only Steven I got mean normalization with some windows behave a certain way by the Linux. It's valid to I guess create pretty much bad many string right, yeah.

B

Basically, the only thing you can't have in a file name is a forward slash. Everything else is valid: even the single space, even a single space, even a random white space, you know unicode characters totally valid, is.

E

The same is true in we know it's just with a two dozen I see the shell of that shell becomes very weird you trying to get director the space very good.

A

Things happen well, I mean the Christian is I mean on Windows. It made that make sense to basically do what the shell does, which is what we have done, but integrations for linux implementation. Would it make sense to apply the shower walls, win32 two things, I guess probably, maybe not right now,.

B

I mean, if anything, you would want to apply the terminal rules on unix, which are they all everything's allowed so yeah you.

A

Don't want to cause, but that would mean that this particular behavior, that we have here where you, if you append the space, would have different behavior on the next, and that will be ok, because it will be expected right. Well,.

B

It's exactly as if anywhere we had spaces here we had some other valid character and will behave exactly like that.

A

Yeah I think that I'm trying to say is it's not so much that one input is legal on Windows and it's legal on linux. It's.

C

D

A

Normalize lazy.

C

A

Peregrine is up-regulated space, so it's not just one case is Faye. Another one is succeeding, is, as you literally have completely different outputs, but I would argue that would be okay, I mean otherwise. You can never get consistency within linux.

B

Sorry, I didn't completely follow that. Can you try.

A

So if you look at the example, you.

E

Never avoid saying the same thing right so.

A

This one here basically would on windows. It wouldn't fail. It would literally just say well create the ecole on excess temp right, because we just trim the trailing space right. Linux II wouldn't trim it. It would literally just create a subdirectory of the space correct, so arguable you could say, there's behavior difference, but I would argue that's expected because in line faucets just behaves differently. Yes, yes,.

A

All right so then,.

A

What was this one for the same one or well.

B

This one is another one, that's a little bit different, it's another inconsistency with the way windows file, move works. But again this is just within.

A

A framework on window huh yeah, so there's nothing to do with cosplay word.

E

This is just sounds like a pipe right. It shows you seen consistent with with her inconsistent with itself that one with.

B

The other methods, so the way it decides between file not found exception and director not found exceptions, is the same throughout all the other functions except for file move. It has a special test on it and if the internal path for the source is it found in the storage.

E

B

We take that not.

E

Today show you, it says it failed and we have no idea why it by which parameters wrong. So then we don't I, think we do a follow-up check to say this provoked, which parameter was actually wrong here to give user it'll burn. But we know 32 just says this file. Yes, it doesn't say it was this parameter in this program or just says the file. So we try to do.

B

A little bit more yeah, we do checks for the destination path, but not the source path and I.

E

State, in other places like in file.

B

Info mu, we do checks for the source path and the destination path, just file that move for some reason. I in case you, these deals, they check the source. Only that.

E

Station so file info and by only okay. So that's.

A

15 in point was the other one file file.

B

And put up, move to and filed up, I'd see.

B

Yeah I think this is another example file copy does the same thing.

B

Apollo copy, if the source is missing a parent directory, then I'll throw our directory not found exception, but file that move we'll just start file not found exception, no matter what yeah.

B

But if we fixed it for the poor, if you fricking change to.

E

Question isn't what is it these kind of change it to ballistics yeah? It's.

C

On it, sound and.

E

Drinking up and you probably the truth, detective.

C

E

Just catch exception.

B

Matthew said, if you like, reliable catch exception, Oh reliable yeah, you guys clearly just but use different exceptions, same problem over.

A

There for my own acceptance, it can be a bit more specific yeah.

B

Biggest other things that aren't I 0 exceptions. That's true! If you can list the number exceptions of file operations, that's longer than just exception to shop, wouldn't leave money's guys.

E

It's agony, section, unauthorized access, except you and all kinds: bio exceptions, no exception and network exceptions; I, don't think we bleed through a network, exception, sure ya, think I know the file system here just catch exception.

C

A

On um I think yeah to David's point I, think I think you should probably just make it proposal what you would like the result to be, and then we can talk about what the ramifications discussed earlier, like as a guiding principle, is have consistency between core course operating systems as possible, and then the second part is: what does it mean everybody pluggable code between full-time writing that stuff? Do we deviate from desktop enough that we should fix desktop?

A

If so, then you probably need to do with EDC review and send it or put that book like um another option, is to just keep with the Dalton favorite behavior with your core, which is called it whatever would use, is the default argument because they would point out these api is a fairly old and fairly long and exists, and then this never registered as a huge issue yeah. Maybe it's just north deviating. It's a pretty.

B

Specific edge case I mean it is inconsistent with the other methods in file, but I didn't see a lot of instances where people actually came upon this issue. If they did, that is caught an eye of exception yeah. So we could leave it there because, just like comment owners of the Ashland and.

A

It look at the last one and then, if I figure on the mouse over two dozen Sweeney real I was just the ad on your mind today we're pretty much done.

C

A

E

E

A

Doesn't just try to adjust the screen to actually allow us to this one thing in the dance that is making omelets no biggie is.

A

Yeah, this is the thing of hot bear. I.

A

Have to look at a different screaming you to the demo, I, don't think you can actually see same there.

C

You just stop the cruise one: I no son should still be running, and hopefully it.

C

Works second screening in and.

A

Yep just switch places.

A

If caps are on table number tip.

C

So let you pass.

F

By Barnes you.

C

To be with counselor, he does still.

B

F

So yes little context here what I work this Homer was on. Implementing a library. I was built, the top of the Numa theory there, which was bringing in manas co to represent the synoptic model. All the metadata objects on an assembly us with a main goal of being able to visit the tree through a visitor pattern and be able the main goal was to be able to round trip and s early through my tool and then run Iowa's top of it and get a run.

F

Yes, so, basically, I'm just going to show a example that had that manages a type reference objects, his daytime and use generics, lambda expressions and throws and catch exceptions and do a road trip of that little demo and run it.

F

So this is basically a console application that I wrote that consumes my library, so, as we can see, we can here is where I create the object for my library and then I get well. This line is not needed, but here I create a file this in this directory and then just call assembly right to and pass the path. This has some bleep right to the only thing that does it starts traversing the three through a visitor that I implemented. That uh is.

F

My yelled string visitor that the only thing that has his head writer and some options either, if you want to show the bytes in the tokens or not and just start writing the assembly through this method right so it starts visiting the whole tree and outputs defied. That makes it so right now the the assembly then gonna run a top of it to.

E

Help set the stage here, you're using our meta data reader. It's a wonderful public on dog, too. You've run an object model around that meta data, reader, yep, you're, simply a reflection, and now you then Berchem help a character to.

C

Output, it I'll doesn't that's right. That's one of the bigger things the pieces was the fact that the missing body parsing was also something implemented. So.

E

I can also email, I guess am elated. Yes,.

F

And you can you can get the actual IL values travers with three, so uh you can do a lot of cool.

C

Like look me, an isle of stuff, something.

F

So basically My Little Women or does got a program that has a daytime object, use reflection. We kiss ass truck that I wrote up right there and what I did is just created a least with some values and then bring the least and then sort the list with a lambda expression then bring the list again and then I grow. The Fibonacci little example to use recursion bring that value, and then I used some reflection and I just bring all the up codes that have an inline, no operand type code Wow.

F

F

C

F

Yep, so if I run this and then go to the directory.

F

What I get this, so this is what my work. So this is what my to output.

F

Right now in single quote: I'm escaping all the names because gene reflection, so some of that data I get some non-belief names for Wednesday, so I last week and run through this.

C

Pretty good how close is output.

B

To like what I'll has an outfit right.

F

The only difference right now, it's pretty much the single escape.

D

My singles yes, so.

F

I'm escaping all the names with single quotes right now, we.

A

Got other whether the string actually needs a stable, so you're over escaping essentially yep.

A

Believe it done it, this between the output like it gives a textual. Do, I guess the textual representation close like is indeed the same. Is that is the lay of the same, or is this.

F

Yeah they, the indenting, is the same. The another difference is they do. A line is paid on an after every parameter, I'm not doing that. Just.

E

Desire doesn't receive it because I see ya, know you're making up the app yeah.

F

So I'll doesn't really be a debug mode and when you use the UI, but when you do al-bassam old dash all and then yes, Emily and dash out and the file to output it it doesn't years to my name- is for anyone. What names? Because looking the names like.

E

These you can PM scores era. Vs Colombians were too complicated right. Do it yep.

C

F

So yeah this is what I put and, if I go sorry.

D

One question so which identifies do need us escaping. You say that you over escape, but what needs escape.

F

So all the msil reserved keywords, Newton's needs skyping, Isis, yeah I know bad all the class names identifiers that that are not a valid identifier name, for example, if it has a baller timer me or if it starts with a special sign or some some those cases.

D

So I planning to fix it to kind of implement the same with object and then don't overstate so.

F

I had something already with regular expressions and stuff like that, but I that purp went down really bad. It.

C

Was gonna follow, Michigan and yet to.

F

Get to do it so right now, I have a case where I only single escape reserved msi awards and what I do with that is. I have a dictionary well set that household msil reserved words and just check if the word is on the hash and singles k plan, but the regular expression I.

E

Wonder I can react with any. You know like you, have that great literary filial index of.

F

Any but the regular expression is for the 2cv. Identifier name is about MSIL Pollock name, but is.

C

It I think we're saying is that it you could check if any of the unlike unalloyed characters are inside the name and in that case just do the escape. It. Ok,.

A

Essentially, you just need to handle two cases. One of them is it's a keyboard, which is the hash set, it testing and the other one is you have any lien valid characters and identify a bit should Oh would be a better, perfect regex. Ok,.

D

Cuz to me like the oldest kept escaping is so yes really there's so much of it. Yes, it makes.

F

It yeah you did it now, so I was able to do these complex demo with uh with reflection in it and feels like expressions are.

C

Getting the display class wasn't watching them, yeah.

A

One thing that would wobble would be nice because some people used at all desert for various reasons that they parser that desertion air that check it in they do dips. It would probably be nice if you could mesh the oil doesn't output if possible, carrier Cabana carica, unless we say they do certain areas that are just completely oddly now it doesn't require fix that. But um it's probably never to be super pretty. I guess, because it doesn't output. I think it will probably be helpful to just match it.

A

For all these reasons, people use it to just didn't. Make this thing easier and stuff like that. To me.

E

If you have a round yep.

F

So right now I'm ready the il, but I showed it was already generated by my tool from the awesome way that I show you that it was the Lund expression, not too short, the least. So right now, if I do I'll awesome food, IL I get the food exhale.

F

So if I do fruit, Alex head bronze, we can see I see here is like welcome.

F

You bring the lace, then sort serious or then calls Fibonacci then bring the D up codes and then throw some exception, catch it and catch it. But.

A

Awesome, that's horrible.

C

What about the ordering of the awkward they are ordering of the members of The Bachelor? It was a purely based on work. I already.

D

C

For sorting room, no.

F

I'm guess I'm just getting them on the order that the metadata reader provides me all. Those types and methods know that, like.

C

If you slightly getting out.

E

That I'm I get.

C

This little diamond, but.

F

I think the methods are sort the same within the classes, I'm not certain about the type definitions, because the methods are served by tokens, but I'm not certain how them at the day worry. There are read, said types yeah.

E

That's right! Oh that's! Right.

A

E

Were on a wider variety now that yeah.

A

E

A

Don't need these uiimage expert. Somebody is pretty good.

A

C

Volunteering, ok, but we folks kill this.

D

Guy just edges of your items: yeah.

C

But it weird oh no, but.

D

C

The the UI guys I'm not lying, oh.

A

Yeah, that's! It has to look shitty right if you.

D

Can otherwise people.

A

Start using it over with um so no what about our goal of the project is the source Abby? Are we going to publish this RB on getting that on github? Yes,.

C

I think I mean she's already working on a branch out of cortex. Where are we graphics, lab I? Think I, don't know we will have it running there. So Lily's.

E

Will be there, can you.

C

E

Iti review up ones like we did.

A

E

A

Interim one another.

C

When you have abs well, no.

F

D

Can open a little bit? You did an apiary real, but we mainly talked about kind of tight 11, yes, objectives since yeah.

A

You had changed significantly. I did to visit area I. Think you change you out there for quite a bit, so I probably wouldn't purchase up.

F

In general da epix file right now, yeah line.

C

Breaking one of that.

A

Oh yeah, what's.

C

A

We climbed, if they'd.

C

A

Spotter would never do that. Never.

C

Will be cruel else inside oh yeah I like what about.

F

After drinking the yeah.

C

So you're right, John, opener, yeah yeah, it's fun.

A

You can you can do they just open API reviewer from FX core it just open it from the command line. No.

C

Yeah FX for food, then.

A

Tools just to back / it out LMK in the reboot. Oh this one yep p render should work.

A

I'll get full man, James and Amar'e.

E

This looks like a great tool: when are we gonna get this.

E

B

C

Sure you could just do that very quickly. Well,.

A

Yeah it's on the list of things. It's actually really easy to think it is. You want excuses. I know, I, have one job.

C

And one of the things we do want to talk about you.

A

Know drop it on wanna, get some red in the edit or not in the left-hand side. Oh yeah. They will Burke.

C

One of the things we're talking about is the name of the assembly and name.

E

Is kind of 2i so to kind of goals here, there's like an object model and let's write it out like I'll, does the kind of thing right there kind of two separate you want to get it just one thing here, because it means in.

A

A

A

Add some comments along the way see it's this guy right.

C

Yeah we currently have an updated the namespace to the to the whatever we have this emily simply because we don't change it twice. Yeah.

F

A

Think last time we talked about the object model. One of the concerns was naming overlap with an actual object model /, whether we can use it object, model espionage, arnold and the last time you every model was very much around the idea that it's being written out, meaning like it had like things like this. I mean culture and string, probably isn't too bad, but flags and some other things were also strings, but some of this has seemed to have changed quite a bit. I.

D

Have to say, one thing that is really unfortunate is that all the type names start with I and I had such a mental block I think the.

C

Idea faces well, the reason why we want is to make it clear, sewing aisle assembly sort.

D

Of assembly, because too oily and I don't.

C

D

A great solutions problem, but it is a problem. Yes,.

C

D

Night, medical is Ellis and be aware. You may have a nice interface for you.

A

Personally, given that it matches my initials and fine looks like I rolled.

C

Always liked it.

E

Anymore, some CD Lentini instructions when.

C

The instructions.

E

D

Everything starts and because he bought it yeah or.

E

A

C

Of it's not much.

A

But you you're missing the L.

C

You to be ail twice: I I lbc bubble.

A

That seems like something you should figure out. What would he do with that? I mean there was also the question like whether we would have an object model in general about the about metadata reader. Yeah um is partly it's very hard to use right now in the sense. So how does the visitor Jimmy Burke you basically just? Have it just have one method for all the objects that makes sense.

A

But everything is: does it's a pool that makes sense to.

B

Y figure the to think well. Well, generally, at the visitors we usually go the abstract base class pattern. Where does the kind.

C

B

Visiting launch digging into signatures and parameters, and things like that, or is this more of a call back, I'll or.

C

Even have a base against the basically.

B

Would have liked either, like you.

C

Would either have to be functional.

B

One where you return the value and you control like base not visit, does the walks the children there's. You have Eva that pattern or the google pattern. We are like return true or false to visit. You know in depth or whatever it seems like here. We have a callback pattern where I can't control the visit like if I'm in signature and I'm like I, don't want to walk signatures defined by c++.

B

That's illegal, C++ C, a lot like how do I know how do I say like when I hit me method, signature like don't visit parameters, I, don't see how do I control that.

A

I think in this moment, I think you, the consumer, is responsible for making sure that everything is visited, that you want to visit. You just don't visit by literally, not know.

C

But I think is saying you own a visit. Some of the parameters not all or I, want.

E

To finish on some of the net site, not all time.

A

That's what I'm saying so like if you're, if you're implementing I visit your right, you implement that say: I method, definition right right and then it's your it's your to all that save in this case will be more like closer I type definition right, but.

E

So is every implementation if I visit earth.

B

And responsible for knowing how to walk all the parameters on the message, there's.

D

A basement there's.

B

C

Physical generally,.

B

It's the other way around that you have a generic visitor, which knows how to walk the things and more her receiver pattern. It seems like it's there.

C

B

C

To string visitor, the kind of does that the normal walk, you'd expected muscular promise in there not over right and what the tutoring visitors seem like I would never look dry. That sure. That's.

B

That's like to do a specific thing, then I would imagine, there's an aisle visitor and then the two-story visitors at derive type. Don't probably that's.

A

Kind of what I would so, what doesn't? As long as you have visitor and walkers right, the visitor literally just handles one in the walkers I'll see to visit the structure right, correct and then you can just do based off blah and then that will walk everything right. Yes,.

C

Yeah that works to work and.

E

So the instruction pattern looks interesting: it also you use with instructions based on it hi, rather than their actual.

F

By your brain type,.

F

Because there is like 350 instructions, so chill motto so on the method: body parsing I, you gotta to salt, to resolve the tokens. You gotta know what the operand type. So we wanted to get rid of that switch statement while going through the opcodes. So the best approach was explaining instructions by objects that represent that opera type. So when you visit that instruction, you know what tocan you're treating and what value your you're looking to. Well as.

C

I of which lets the switch statement switch statement that.

E

Doesn't have a patrol because junks it has.

F

E

On me, it doesn't have it tied, it doesn't have a the thought has opened yeah. Well what rumors.

F

Did the person so the operand is di oxide with Arsenal and then he has a jump. So you can help with.

E

What labels do want to jump, but how do I know what the time is to the screech neck, but.

C

A

If nick is.

C

Well, like that, I'm I've.

E

Done switch on it, ain't right.

A

On the switch I, don't think they do, is they give you look at il instruction.

A

Then you have the opcode and then based on what the op code is. You know yeah, but the fifth instance of our instructional, so you would have to basically switch in their cars I. Think that's the idea.

F

So to know what your switch, not you could check the the previous instructions, what you love it into style.

F

Because the switch instruction, what does is it takes the latest value in the stack and switches against it?.

C

This is similar to like calling me any missile or anything right, yep bushings that were on times on the stack and this.

E

Is your happy I did.

C

I couldn't remember.

E

How to represent Rosen.

A

E

Use this for shame it very often so instruction it uses branches. What I.

C

A

Do you look into whether you can just have visited have representing I'll instruction construct as opposed to having an errand turkey yeah.

C

You thought about that yeah. It would just make it a lot more bubbly.

C

You have to know where which Hadfield unobstructed get dog the option out for each other's instructions. The.

D

User of the APA, we're always like to do this with Steve, a very outgoing. Thank you cast evaluation with the Anthony they're done right, timid,.

A

In this case, when using visit battery already half, do you think that's which affected? Will you let you don't have visitors specifically for the instructions you.

C

Doing everyone, an instructor, doesn't entice.

A

Well, I guess you could still have that right could just have different method, names or different. Overlooks that actually give you it's one type arguments in there. I am just trying to think of you. If you run I'll doesn't let say against a large table with thousands of method bodies right, you're, allocating a ton of stuff, as you go, didn't.

D

We talked last time about kind of breaking this whole library into two separate features, one very low level kind of corresponding to you know the metadata reader, which is optimized for pervs and then on top of it building. Something to you know, generate text, for example, yeah.

E

D

E

We talked about this lesson now. I was but yeah.

A

No II national comments.

E

Yeah, the other thing is, we have to cut it. We've been holding off writing an object model on this thing because we didn't what is it to write an object model because there are already existing object. Poles, we have to kind of trade.

A

E

Off, like you know, do we just grab CC I, see someone and existing metadata. It isn't just set them on top of the spread. On top of that, the metadata reader. Where do we go.

D

And write an object.

E

Model, it's now like branch from those things so I.

A

Started to play with playing an object model of the most trickiest part. Is it's very hard to get the convenience of what was in reflection as without resolving once you do resolving you basically go down a path that it gets very quickly very complicated.

A

E

If you branch refs from net so.

A

Well, that's one thing: I, the other part of it is there's certain things I had to do. Parsing, where cci kind of cheats a bit and it doesn't is not necessarily always well defined. I mean I talked with Nick about this for a long time that we couldn't come up with a way that we're guaranteed you working in all cases at. Why not it's.

E

The enum pet yeah Liam case and then there's the other priority have that from regardless. You know people you try and read an enamel on how much it's true.

A

Whether the way about 80 reader is implemented like you, because you're worth watching for parsing click and everything, it's your father, essentially at all 11.

E

We're adding attribute so we have to solve them. Yes,.

A

And the way I think API thought is you ask with the sides, so you have to know pull it out of thin air and.

A

E

A

Cool I did any more feedback, I would just say, let's rev up people time back just.

D

Smelling it I visitor is such a genetic thing. I would make it less genetic, especially.

B

At the listener.

D

C

D

Yo, can we change it to something you know? Maybe you can think about something like we. Let say.

F

A lesson for chick-fil-a on the previous descending you so we.

C

Will you keep that recursion I.

D

Would love a little something to die? Do something cil yeah, maybe.

E

B

A framework design guys: oh ok, I, don't as I say, I, don't have a solution of.

A

This problem I mean a.

B

Dwell on it over.

D

C

D

I come up with something I.

C

D

E

It you know, I, want to show your in this library.

E

Have xray that was your prefix.

D

I see is that way.

D

Ma BF x is better, let's go over know.

A

About Casey to initial tiny, the head of the mind is that is.

D

Cord isn't cold, then.

C

You think open I am.

A

E

A mighty I yeah.

A

C

A

It makes it come people used the only remaining question that we have is there a place of the neck or design reviews there is its own YouTube will send a link on twitter later, alright guys, then thanks for joining us and then I'll upload. It later same.