Action stopped working on `macos-13` - was: Hangs indefinetely on `macos-13` after `brew update`

[Andrej730]

Hi! Not sure when, but recently the workflow broke (it hangs for a very long time and never finishes) if used with macos-13 runner and has brew update before it, see example yml below.

You can use this repo to reproduce the issue - https://github.com/Andrej730/ccache-bug-report

It has test workflows for macos-13 (hangs), macos-14 (works fine, ccache step is finished 17 sec), macos-13+no brew update (works fine, ccache is finished in 13 sec)

On a side note, macos-13 is based on macos 13 and intel, but confusingly macos-14 is based on macos 14 and arm64 (see https://github.com/actions/runner-images#available-images). So it be some kind of problem on intel machines.

Example yml:

name: macOS ccache Hang Investigation

on:
  workflow_dispatch:

jobs:
  investigate-ccache-hang:
    runs-on: macos-13
    
    steps:
    - name: Checkout code
      uses: actions/checkout@v4
      
    - name: Update Homebrew
      run: brew update
      
    - name: ccache
      uses: hendrikmuhs/ccache-action@v1.2
      with:
        key: mac-${{ runner.arch }}
      
    - name: This step should run
      run: echo "This step runs after ccache."

[hendrikmuhs]

It seems brew removed pre-compiled bottles for macos-13:

https://github.com/Homebrew/homebrew-core/pull/241789/files

That's why the workflow compiles it from source and takes very long. The uncached version grabs the older version which still has a precompiled ventura package.

On a side note, macos-13 is based on macos 13 and intel, but confusingly macos-14 is based on macos 14 and arm64 (see https://github.com/actions/runner-images#available-images). So it be some kind of problem on intel machines.

Yeah, that's the problem here. But doesn't macos always cross-compile for arm and mac?
The only other option seems macos-15-intel (there is no macos-14-intel).

Anyway, this situation seems to be caused upstream, I don't know what this action can do. One could detect macos-13 and pin the version of ccache in the hope brew doesn't delete the package from their servers. Not running brew update, won't work very long: github updates runner images on a regular basis. However, I do not really like that solution to be honest. I think the best would be, if you install ccache yourself before running the action.

I guess it depends for how long you want to build macos-13 packages. github also marked them deprecated. Maybe it is time to move on and drop macos-13 support, too?

[hendrikmuhs]

Official PR to drop ventura: Homebrew/brew#20672

Announcement: https://docs.brew.sh/Support-Tiers#future-macos-support

I am disturbed by that. Ventura's EOL is November 2025. Brew dropped support before the official EOL.

[hendrikmuhs]

Here is another one: https://github.blog/changelog/2025-09-19-github-actions-macos-13-runner-image-is-closing-down/

In short: github will remove macos-13 runners December 4th 2025. For me it therefore makes no sense to implement a workaround in this action for a dying platform. For the remaining 2 months projects can:

• build without ccache support
• switch to sccache
• find ways to pre-install a working ccache binary
• use the macos15-intel(free) or macos-14-large(paid) runner

For my OSS project I will switch to macos15-intel. As announced by github this is supposed to work till Fall 2027.

@Andrej730 Thanks for bringing this up.

I will keep this issue open for a while, I guess others will run into this, too. However I will change the title.

[Andrej730]

Thanks for looking into this. If possible would be nice if ccache workflow can issue some kind of warning about expected issues on macos-13 runner, so users can navigate to the solution more quickly.

---

I end up switching workflow in my project to cross compilation on macos-14, thought maybe it's better to keep the same os version for now for both arm64 and intel builds, but that wasn't a very smooth process - some libs (or their older version) may not support cross compilation in a straighforward way. So using macos-15-intel is probably much simpler solution to pull off.

[hendrikmuhs]

Note, I have neither been involved regarding the changes in homebrew nor github.

I am frustrated as anyone else when upstream projects introduce backwards incompatible changes. Github announced the changes and they provide warnings. But brew keeps breaking packages, its a fragile ecosystem if you ask me.