Background:
Attempting to upgrade large 100k codebase from Swift 2.3 to Swift 4. Was making good progress, fixed ~1000 error. Then, after changing one of our DTO objects to use Any instead of AnyObject (because we had to), the compiler started hanging.
Problem:
When compiling the application will get to a certain file and just get stuck (even after 24 hours). It is not frozen just stuck compiling. I have tried temp removing the file but then it just gets stuck on another file and so on and so on.
Research & Attempts
I've read up on the compiler and how to turn on warnings and flags. I tried looking at -Xfrontend -debug-time-function-bodies and -Xfrontend Xfrontend -warn-long-expression-type-checking but nothing comes up. When I look at the build transcript for the file its stuck on there is no info in the expanded transcript.
Do you know what else I can check? I suspect it has something to do with its inability to infer type given how many Any filled dictionaries we have but without getting better information I have no clue where to go from here.
Do you know how I can get info as to why it's getting stuck on this file and no warnings given?
To followup, it took several days, but by first converting to Swift 3.2 and then Swift 4 (commenting out most code to solve later) I was able to get it to compile in Xcode 9.
Related
I have recently updated to macOS 13.0 and for that minimum XCode Version required is 14.x series. But my existing project never getting successfully building. Its getting stuck at some point.
Its not getting failed. Build process screenshot is attached below. Its not pointing to any specific class. Seems like there are lots of classes which are getting compiled successfully at last but still build process is stuck at some point:
Seen similar threads like below on apple pages but nothing seems working. Does anyone got resolution?
Xcode 14 project compile error
XCode 14 compile errors immediately disappear or do not appear at all
Something similar has happened to me in the past on a number of occasions. If the Swift compiler is hanging mid-build, usually the issue is that there is some expression that is too complex for Swift to do the type inference on.
What you need to do is first find the exact statement that is causing the hang. This is how I do it:
First find out which source file is causing the problem. Look at the build log to figure this out (the build log can be located by looking at the reports navigator ⌘9 ). Find the build log and click on it. The build log will appear in an editor window.
One of the compiles will still be in progress and its file is the one you want.
The next thing to do is comment out all the code and recompile. This time the compilation will finish (if you have the right file, or there is only one) but probably with a lot of errors. Then you add the code back in, function by function, until one of them causes the compilation to hang again. If it's not obvious which line of the function is causing the problem, comment it out again and then add the lines back one by one until the compilation breaks again.
Once you have located the line, you need to simplify the type inference on that line. If it's a closure, try adding an explicit declaration for its parameters and return type. If it involves some complex array, try adding a type annotation to its declaration. Also try breaking down complex expressions into multiple simpler expressions.
There's no one size fits all answer to this but usually, once you have located the exact line that is causing the problem, it should be reasonably obvious how to fix it.
I am posting this after reading many similar posts on here regarding this issue and none of the solutions that worked for other people not working...
Xcode Version 8.3.3 (8E3004b)
Swift 3.1
Things I tried
Deleting Derived Data folder
Deleting Workspace File
Cleaning Build Folder
Cleaning Build
Reinstalled Xcode (after complete removal)
I also looked for Swift Issues:
Removed all concatenating strings
Cleaned up Swift arrays and dictionaries
Added Whole module optimizations
This all started happening after last Xcode update of 8.3.3. My project was compiling within seconds and now I have to wait at least 15 mins for it to index, then 5 minutes to compile after everything I change even something small in code.
When Building, it get stuck in "Compiling Swift source files". Is there way for me to look in to where it is actually getting stuck?
BIG UPDATE
I tried pretty much everything. Read every article, post, ect. NOTHING worked. My project was created right after 10.0.
Solution
Creating a new project and copying each file worked! It used to take 8-9 minuted to build. Now less than 2 seconds!
Apple knows about this problem, and says that Xcode 9 beta will perform much better. Note that if you don't want to update to Swift 4, you can continue compiling in Swift 3 mode using Xcode 9. The big limitation is that you won't be able to submit your project to the App Store until Xcode 9 goes final.
Also, Xcode 9 contains a new build system. You don't get it by default: you have to turn it on for this project. Choose File > Project Settings and switch the pop-up menu to New Build System (Preview). This is experimental, but it will be the default build system eventually, so it would be interesting to know whether this makes an appreciable difference.
If you don't want to update to Xcode 9 beta, you will just have to do a binary search: comment out all your code and start adding it back, piece by piece, until you find that piece that's causing the trouble.
The best way to work this out is to find what out what the build is doing while compiling your code. This is a really useful tool to use: https://github.com/RobertGummesson/BuildTimeAnalyzer-for-Xcode
When you run this tool it will show you what methods are taking the longest to compile, and then you fix those. Once you have done that, you can also try the answer I gave here to decrease the build times: Extremely long compilation times with Swift in Xcode
I have upgraded Xcode 8 but when I'm debugging, every object showing following error :
expression produced error: error: Couldn't materialize: couldn't get the value of __once: extracting data from value failed
error: errored out in DoExecute, couldn't PrepareToExecuteJITExpression
This seems system level error, so I've already tried all possible solutions but still doest work.
I don't know of any bug that would cause this to happen for all types. Except, if this is a Swift project, make sure that you have cleaned and rebuilt all the swift code you depend on from source. At present, Swift really needs the whole world to be built consistently for debugging to work. If that doesn't help, then we will need more details to figure out what is going wrong.
Might be worthwhile to file a bug with http://bugreporter.apple.com since that makes gathering the data needed to solve the problem easier.
This Issue Occurred On A SpriteKit Xcode Project
I have an issue with Swift where, once my project reaches a certain level of complexity where I have tons of classes and methods around, my autocompletion breaks so that "Jump To Definition" ceases to work and my IDE is reduced to the usefulness of a basic TextEditor/Notepad.
My code's color will change to white completely, which causes a lot of strain on my eyes, and this seems to only happen when I remove and add large blocks of code as I watch my CPU activity climb up to 75% usage on all CPU cores.
I think this started happening when I switched the target iOS from 9.3 over to 8.0. Is this an issue with the compiler trying to interpret old Swift syntax?
I also will have cases where I wait two minutes for minor changes to compile, only for the build to fail due to "Linker command failed with exit code", which is easily fixed by compiling twice.
Here's my specs:
OS X 10.11.4
Core i7 Skylake 4.0GHz
16 GB DDR4 RAM
256GB SSD
I'm thinking about building a system running OS X with dual processors which might alleviate the issue, since it can take upwards of 2 minutes just to compile code that's different by 1 line.
Okay, I found one solution which resolved my issue.
Remove All Emojis From Variable Names & .Swift File Names
Contrary to Apple's official Swift 2.0 textbook, DO NOT use ANY kind of Emoji's for things like Variable Names and Swift File Names UNLESS you know that the emoji you're using is a very old emoji (but even then, I wouldn't recommend it).
After opening my project in AppCode, AppCode had unicode problems with file names such as: foobar🔵.swift. It was very buggy and it would break Xcode later if I opened and saved a project with pre-existing emojis in AppCode.
So avoid using emojis in your code unless it's for strings like:
let someString = "⬛️🗡💣📚"
Welcome to Swift! Great language, awful tooling.
Joking aside, there are a couple of issues at play here. First off, syntax highlighting disappears when SourceKit crashes. SourceKit is the library which parses Swift on-the-fly so that Xcode can do things like indexing, syntax highlighting and code completion. It's a lot better than it used to be (using Swift 1.0 in Xcode was almost comical at times), but it's still far from perfect. Until SourceKit improves, you won't see much difference.
As for your build times, it's worth trying something like the Swift Build Time Analyzer to see which functions are taking a particularly long time to compile. I recently halved the compile time of the project I work on by removing all lazy vars set via closures. A recent compiler change made type inference for these sorts of closures incredibly slow, so each one was taking ~6 seconds to compile.
I have a strange issue that I haven't seen or read about anywhere else. My Xcode no longer parses all of my files to find issues/errors. It will display any issues or errors in a file I am currently viewing, and these will persist thereafter, but with 400+ files I can't reasonably visit each one to make it compile. Xcode can build successfully if the code is valid, however I can never know when that is, since I see no errors. Indexing occurs, but no compiling takes place.
Also, when building, the status bar states that Xcode is compiling x out of however many total compile sources but the total number is usually not even close to the actual total number. For example it may say compiling x out of 40 files when there are actually 400 compile sources.
I wasn't doing anything out of the ordinary from my usual tasks when this issue began. New projects will compile, then randomly stop compiling after a period of time.
Things I have tried:
nuking derived data
quitting Xcode/restarting computer
Recloning the project from a known working repository. It will build but won't find errors/issues when they do exist. There should be at least a handful of minor issues but none appear.
Reinstalling Xcode (4.5.2)
tried both GCC 4.2 and LLVM 4.1 compilers
Has anyone experienced this issue before and found a solution? This problem has made my job extremely difficult and any help would be much appreciated.
It does sound like corruption of DerivedData. Try this:
Clean your target: cmd+shift+K or Product->Clean
Quit xcode
Delete the contents of /Users/your_user/Library/Developer/Xcode/DerivedData
Restart xcode
(It's safe to delete this folder's contents. But if you're nervous about that, back it up first).
You should be good to go.