XCode 10: -Wauto-var-id raises several warnings

After updating to XCode 10, the -Wauto-var-id warning is raised in several JUCE module files, e.g.:

In file included from /Users/work/Documents/pluginval/JuceLibraryCode/include_juce_gui_extra.mm:9:
In file included from ../../modules/juce/modules/juce_gui_extra/juce_gui_extra.mm:27:
In file included from ../../modules/juce/modules/juce_gui_extra/juce_gui_extra.cpp:133:
../../modules/juce/modules/juce_gui_extra/misc/juce_RecentlyOpenedFilesList.cpp:161:9: error: 'auto' deduced as 'id' in declaration of
      'sharedDocController' [-Werror,-Wauto-var-id]
        auto* sharedDocController = [NSDocumentController sharedDocumentController];

This breaks build scripts that treat warnings as errors, such as @dave96’s pluginval.

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How are you enabling the warning? I’ve added -Wauto-var-id to the Extra Compiler Flags section of the Projucer’s Xcode exporter but I’m not getting these warnings after re-saving and opening in Xcode 10.

I didn’t manually enable the warning, I just got it :confused:

Hmm still not seeing it, even with -Weverything turned on. What project are you building?

It happens to me when building any JUCE project, for example when executing the buildscript of https://github.com/Tracktion/pluginval.

I’ve done a bit of research, and it seems like -Wauto-var-id is a clang-only warning. I couldn’t find out in which verson of clang it was introduced, but perhaps you’re using a different compiler (version)?

> clang --version
Apple LLVM version 10.0.0 (clang-1000.10.44.2)

No, doing:

/Applications/Xcode-beta.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang --version

gives me

Apple LLVM version 10.0.0 (clang-1000.11.45.5)

I’m at a bit of a loss on this one, perhaps other people are seeing the same warning and could chime in?

I’m on macOS 10.14 (Mojave), and got XCode Version 10.0 (10A255).
I can’t think of any other differences we could have in our setup.

I noticed you’re using Xcode-beta.app, while I use a full release - perhaps that’s the relevant difference?

Nope, I’ve tried with both. In the line which you’ve posted can you try changing:

auto* sharedDocController = [NSDocumentController sharedDocumentController];


auto sharedDocController = [NSDocumentController sharedDocumentController];

and see if the warning goes away?

Yes, that indeed fixes the warning.

I would like to help you by eliminating all of the respective warnings and making a PR, but when updating from the latest JUCE release’s modules folder to the develop branch’s latest tip, it doesn’t build anymore…

/Users/work/Documents/JUCE/modules/juce_video/native/juce_mac_Video.h:223:52: No type or protocol named 'NSKeyValueChangeKey'

This is probably related to macOS 10.13 Deployment Target: AU build fails.

I’m starting to believe there’s something terribly wrong with my setup…

Are you sure you’ve updated the modules fully and you’re not mixing-and-matching JUCE versions? What tool are you using for version control?

I’m using git for version control.

When starting out with JUCE, I’ve been using the modules from the JUCE folder I downloaded with the latest release (I didn’t know I could also pull them from Github).

I now switched to the modules on the develop branch by cloning it from git, setting it as the global modules path and enabling “Use global path” for each module:

I like to believe I know what I’m doing, but there has to be something off about my setup.

Yeah that all sounds correct. Just to double-check: you’ve set all of the modules in the project to use the global path which contains the latest modules? And re-saved the project in the Projucer? It might be worth also trashing the Builds folder of the project and re-saving just in case.

Yes, I did a double-check - all modules set to global, the global path is correct, and this is the git status of the modules folder:


I trashed the Builds folder, executed Clean Build Folder in XCode - same errors.

Hmm, OK I’m not sure what could be going on there sorry. I’ll do a quick skim of the codebase and remove all of the id -> auto* conversion warnings though.

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