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Dockerfile: remove g++-12 from Ubuntu 24.04#21613

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MikeMcQuaid merged 2 commits intomainfrom
ubuntu24.04-remove-gcc12
Feb 23, 2026
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Dockerfile: remove g++-12 from Ubuntu 24.04#21613
MikeMcQuaid merged 2 commits intomainfrom
ubuntu24.04-remove-gcc12

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@cho-m
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@cho-m cho-m commented Feb 22, 2026

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We will want to use g++ == g++-13 when moving to Noble so avoiding installing g++-12. Also move out skopeo from conditional as we no longer need Ubuntu 20 or older.

May start looking into moving to Ubuntu 24.04 earlier as we have our first impacted formula that has multiple dependents:

Copilot AI review requested due to automatic review settings February 22, 2026 19:37
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Pull request overview

Updates Homebrew’s Ubuntu-based Docker image setup to align compiler tooling with Ubuntu 24.04 (“Noble”) by avoiding installation of the older g++-12 package there, while keeping it available for Ubuntu 22.04 (“Jammy”).

Changes:

  • Install skopeo unconditionally in the main apt package set.
  • Restrict g++-12 installation to Ubuntu 22.x only (no longer installed on 24.x+).

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@carlocab
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Does upgrading GCC not work for Z3?

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cho-m commented Feb 23, 2026

Does upgrading GCC not work for Z3?

The final goal of changes is to upgrade GCC as Z3 needs a newer libstdc++ so will be a runtime dependency. Specifically, Z3 needs support for std::format (GCC 13 library) and building with GCC 13 will add GLIBCXX_3.4.32 requirement (GCC 13 ABI)

We don't want to use brew gcc given Z3 has ~500 dependents which will bring back the same issue we saw when using Ubuntu 16.04 and were trying to avoid via the Linux GCC-only audit.

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Thanks!

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May start looking into moving to Ubuntu 24.04 earlier as we have our first impacted formula that has multiple dependents:

@cho-m What's your suggested timescale? Note we'll land 5.1.0 any week now and 5.2.0 will be ~3 months after that (in case one of them is worth aiming for).

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cho-m commented Feb 23, 2026

What's your suggested timescale? Note we'll land 5.1.0 any week now and 5.2.0 will be ~3 months after that

Based on those dates, could target 5.2.0 for actual migration and add an advance notice in 5.1.0.

Mainly since Ubuntu 26.04 release is April 23 and one idea we had in a prior discussion was to stay on 2nd latest LTS.


Non-impacting changes like these can be merged now. Could also move some non-bottling CI to Ubuntu 24.04 to get a better idea if anything is broken.

Impacting changes like glibc (Homebrew/homebrew-core#268900) will need to be timed closer to migration.

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Based on those dates, could target 5.2.0 for actual migration and add an advance notice in 5.1.0.

@cho-m Sounds good. Could you try to land any "advance notice" code changes this week? If it's docs only: can you just dump here or in Slack what I should put in release notes? Thanks 🙇🏻

@MikeMcQuaid MikeMcQuaid added this pull request to the merge queue Feb 23, 2026
Merged via the queue into main with commit 5dfbb56 Feb 23, 2026
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@MikeMcQuaid MikeMcQuaid deleted the ubuntu24.04-remove-gcc12 branch February 23, 2026 17:46
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cho-m commented Feb 23, 2026

@cho-m Sounds good. Could you try to land any "advance notice" code changes this week? If it's docs only: can you just dump here or in Slack what I should put in release notes? Thanks 🙇🏻

Will add a brew doctor message for upcoming glibc. Still need to fix some things but working on this in

Optionally release notes could include "upcoming changes" section which mentions something like: we will update CI to Ubuntu 24.04 increasing minimum glibc to 2.39 and libstdc++ to 6.0.33.

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