gcc failed to update - Warning: The post-install step did not complete successfully

[abitrolly]

Additional Info

• I am using Windows Subsystem for Linux

Output of brew config

HOMEBREW_VERSION: 6.0.6-16-g8d94d5c
ORIGIN: https://github.com/Homebrew/brew
HEAD: 8d94d5c7cffe2c104a27c92605f6f8df3767338c
Last commit: 6 hours ago
Branch: main
Core tap HEAD: 9d7749ee6897ab65e9729dbca99123ee9977d45c
Core tap last commit: 25 hours ago
HOMEBREW_PREFIX: /home/linuxbrew/.linuxbrew
HOMEBREW_CASK_OPTS: []
HOMEBREW_DISPLAY: :0
HOMEBREW_DOWNLOAD_CONCURRENCY: 8
HOMEBREW_FORBID_PACKAGES_FROM_PATHS: set
HOMEBREW_MAKE_JOBS: 4
HOMEBREW_REQUIRE_TAP_TRUST: set
Homebrew Ruby: 4.0.5 => /home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/bin/ruby
CPU: quad-core 64-bit haswell
Clang: N/A
Git: 2.54.0 => /bin/git
Curl: 8.15.0 => /bin/curl
Kernel: Linux 7.0.13-100.fc43.x86_64 x86_64 GNU/Linux
OS: Fedora Linux 43 (Workstation Edition)
Host glibc: 2.42
Host libstdc++: 6.0.34
/usr/bin/gcc: N/A
/usr/bin/ruby: N/A
glibc: N/A
gcc@13: N/A
gcc: 16.1.0
xorg: N/A

Output of brew doctor

Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: Some installed kegs have no formulae!
This means they were either deleted or installed manually.
You should find replacements for the following formulae:
  p9ufs

Warning: No developer tools installed.
Install Clang or run `brew install gcc`.

Warning: You have uncommitted modifications to Homebrew/homebrew-core.
If this is a surprise to you, then you should stash these modifications.
Stashing returns Homebrew to a pristine state but can be undone
should you later need to do so for some reason.
  git -C "/home/linuxbrew/.linuxbrew/Homebrew/Library/Taps/homebrew/homebrew-core" stash -u && git -C "/home/linuxbrew/.linuxbrew/Homebrew/Library/Taps/homebrew/homebrew-core" clean -d -f

Uncommitted files:
  ?? Formula/p/p9ufs.rb
  ?? Formula/r/rquickshare.rb

Description of issue

While updating dependencies gcc failed to install.

==> Pouring gcc--16.1.0.x86_64_linux.bottle.1.tar.gz
Warning: The post-install step did not complete successfully
You can try again using:
  brew postinstall gcc

There is no cc or gcc available after the install, and brew doctor also complains about that.

Warning: No developer tools installed.
Install Clang or run `brew install gcc`.

Running brew postinstall gcc --debug --verbose gives this trace.

brew postinstall gcc -d -v
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/brew.rb (Formulary::FromAPILoader): loading gcc
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/brew.rb (Formulary::FromAPILoader): loading homebrew/core/gcc
==> Postinstalling gcc
Warning: The post-install step did not complete successfully
You can try again using:
  brew postinstall gcc
==> An exception occurred within a child process:
  ErrorDuringExecution: Failure while executing; `/usr/bin/cc -print-file-name=crti.o` exited with 127. Here's the output:


/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/utils/popen.rb:21:in 'Utils.popen_read'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/utils/popen.rb:33:in 'Utils.safe_popen_read'
/home/linuxbrew/.linuxbrew/opt/gcc/.brew/gcc.rb:185:in 'Formulary::FormulaNamespacefec222da6f944914faf717ed4edc754ea2ec146acab1fab4465fde78f658afcb::Gcc#post_install'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/formula.rb:1656:in 'block (3 levels) in Formula#run_post_install'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/formula.rb:1461:in 'Formula#with_logging'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/formula.rb:1655:in 'block (2 levels) in Formula#run_post_install'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/extend/kernel.rb:234:in 'Kernel#with_env'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/formula.rb:1651:in 'block in Formula#run_post_install'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/vendor/portable-ruby/4.0.5_1/lib/ruby/4.0.0/tmpdir.rb:105:in 'Dir.mktmpdir'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/formula.rb:1642:in 'Formula#run_post_install'
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/postinstall.rb:35:in '<main>'

So what is going on here?

[SMillerDev]

You don't have a local C compiler? Have you tried installing one?

[abitrolly]

@SMillerDev I can try, but expected that brew install gcc does it.

[abitrolly]

@SMillerDev the requirement to have C compiler installed to install gcc looks like a zip.zip problem to me. Can it be avoided? Instructions at https://docs.brew.sh/Homebrew-on-Linux doesn't mention this requirement.

[SMillerDev]

Instructions at https://docs.brew.sh/Homebrew-on-Linux doesn't mention this requirement.

Is the c compiler not part of the development tools it tells you to install? That seems unlikely.

[abitrolly]

@SMillerDev installing system wide gcc fixed the thing. Thanks.

$ brew postinstall gcc -v -d
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/brew.rb (Formulary::FromAPILoader): loading gcc
/home/linuxbrew/.linuxbrew/Homebrew/Library/Homebrew/brew.rb (Formulary::FromAPILoader): loading homebrew/core/gcc
==> Postinstalling gcc
==> Creating the GCC specs file: /home/linuxbrew/.linuxbrew/Cellar/gcc/16.1.0/bin/../lib/gcc/current/gcc/x86_64-pc-linux-gnu/16/specs

I wish the error message was more clean. The brew doctor diagnostic is also misleading - brew install gcc didn't help. Installation requirements can also be more specific and link to why exactly GCC is required (why it is needed to create GCC spec file for brew install gcc?). Maybe it is still possible to avoid system GCC if gcc formula is fixed to work without it?

[abitrolly]

Proposed a fix to doc Homebrew/brew#22921 but I feel like the real patch belongs to brew doctor.

[p-linnane]

This should be made clear by Homebrew/brew#22925.

[Bo98]

The answer here is technically a bit more nuanced.

If you are installing both glibc and gcc then you don't actually need a system compiler. It will use the crt*.o file from Homebrew's glibc.
If you are only installing gcc then it needs libc6-dev from the host and a system compiler configured to find the path. The latter is something we may accept a pull request to improve if there's an alternative reliable way to locate crt*.o file on the system across all Linux distros. But right now, the system compiler is what is used to reliably find these files. In any case, you must actually have the crt*.o files on your system from libc6-dev so that part of the requirement still stands.

If you are on a system where you need Homebrew GCC but cannot install libc6-dev, or a system compiler to find crt*.o, then it is still possible to use Homebrew without a system compiler by using brew install glibc. This is technically a tier 2 configuration so it's only something I recommend if you cannot fix it via other methods.

You can also use Homebrew without using GCC at all. So Homebrew doesn't need any of this if you never install GCC or anything that depends on it. Obviously this may be limiting depending on your circumstances. Homebrew GCC is only a hard requirement for everything if your libstdc++ is older than 6.0.33 (at the time of writing).

[cho-m]

crt*.o would be automatically found on Debian derivatives using same filesystem layout since we build on Ubuntu. Though given user is on Fedora which uses /lib64, GCC will need the post-install symlink.

A last attempt fallback could be to search the ld.so directories. This is only a subset of GCC's search path so may not work on all Linux, but at least can find it on some major distros with common hierarchies

• Ubuntu

  $ brew ruby -e 'p OS::Linux::Ld.system_dirs(brewed: false).find { |dir| File.file? "#{dir}/crti.o" }'
  "/lib/aarch64-linux-gnu/"

• Fedora

  $ brew ruby -e 'p OS::Linux::Ld.system_dirs(brewed: false).find { |dir| File.file? "#{dir}/crti.o" }'
  "/lib64/"

[abitrolly]

If you are installing both glibc and gcc then you don't actually need a system compiler. It will use the crt*.o file from Homebrew's glibc.
If you are only installing gcc then it needs libc6-dev from the host and a system compiler configured to find the path.

On Fedora gcc depends on glibc-devel, so it is not possible to install it without glibc.

[abitrolly]

You can also use Homebrew without using GCC at all. So Homebrew doesn't need any of this if you never install GCC or anything that depends on it. Obviously this may be limiting depending on your circumstances. Homebrew GCC is only a hard requirement for everything if your libstdc++ is older than 6.0.33 (at the time of writing).

If Homebrew works without host GCC, it would be nice to get this clarified in the docs. And instruct the user to install it in a friendly manner when the GCC is actually need to be used.

[Bo98]

On Fedora gcc depends on glibc-devel, so it is not possible to install it without glibc.

I was referring to Homebrew glibc and Homebrew GCC in that message, with libc6-dev referring to Fedora's glibc-devel.

If Homebrew works without host GCC, it would be nice to get this clarified in the docs. And instruct the user to install it in a friendly manner when the GCC is actually need to be used.

Yeah I agree that we should improve the GCC formula.