Show 27 quoted lines
> On Fri, 20 Mar 2026, Johannes Schindelin wrote:
>
> > On Fri, 20 Mar 2026, Junio C Hamano wrote:
> >
> > > The build seems to have started failing on macos-14 CI jobs at
> > > GitHub, however, as apparently not all the macOS platforms have this
> > > flag defined.
>
> [... I need to ...] recommend something like this in the `Darwin` clause
> in `config.mak.uname`:
>
> -- snipsnap --
> diff --git a/config.mak.uname b/config.mak.uname
> index f9ffefa67a4f..572f8967bc36 100644
> --- a/config.mak.uname
> +++ b/config.mak.uname
> @@ -172,6 +172,10 @@ ifeq ($(uname_S),Darwin)
> NEEDS_GOOD_LIBICONV = UnfortunatelyYes
> endif
>
> + ifeq ($(CC),clang)
> + NO_REGEX = HomebrewsClangSeemsToBeMissingEnhancedRegexSupportAsOfMarch2026
> + endif
> +
> # The builtin FSMonitor on MacOS builds upon Simple-IPC. Both require
> # Unix domain sockets and PThreads.
> ifndef NO_PTHREADS
Turns out that my analysis was not _quite_ complete yet. With Claude Opus' assistance, I was able to find the exact turn of events that led to the CI failure. Here is my proposal for an alternative to your patch, Junio (the https://github.com/git-for-windows/git/actions/runs/23335584918 shows that the build completed successfully this time; the tests are still running as of time of writing, of course):
-- snipsnap --
From f65b3b657c36e9132624ea223c90047527edea59 Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 20 Mar 2026 09:09:10 +0100
Subject: [PATCH] osx-clang: work around Homebrew's clang lacking REG_ENHANCED
The `osx-clang` and `osx-reftable` CI jobs on macOS started failing with:
compat/regcomp_enhanced.c:7:13: error: use of undeclared identifier
'REG_ENHANCED'The failure coincides with the GitHub Actions `macos-14-arm64` runner image being updated from `20260302.0147` to `20260317.0174`. The key change in that image update is the Homebrew version bump from 5.0.15 to 5.1.0.
Homebrew 5.1.0 introduced automatic linking for versioned keg-only formulae when the unversioned sibling is absent (see https://github.com/Homebrew/brew/pull/21676, announced at https://brew.sh/2026/03/10/homebrew-5.1.0/). The runner image installs `llvm@15` (keg-only) but not unversioned `llvm`. Under Homebrew 5.0.x that formula stayed in its keg and its `clang` binary only lived at `$(brew --prefix llvm@15)/bin/clang`. Under 5.1.0, because unversioned `llvm` is absent, `llvm@15` is now auto-linked into `/opt/homebrew/bin/`, which sits earlier in PATH than `/usr/bin`.
The net effect is that `CC=clang` in CI now silently resolves to Homebrew's LLVM 15.0.7 clang instead of Apple's system clang (Apple clang 15.0.0, bundled with Xcode 15.4). The runner image README confirms this: the reported "Clang/LLVM" version flipped from 15.0.0 to 15.0.7 between image releases, matching the Homebrew LLVM version exactly.
Homebrew's LLVM clang uses different include paths from Apple's clang. In particular, the `regex.h` it sees does not define `REG_ENHANCED`, which is an Apple-specific extension present in the macOS SDK headers since at least macOS 10.12. The Makefile unconditionally sets `USE_ENHANCED_BASIC_REGULAR_EXPRESSIONS` for all Darwin builds via `config.mak.uname`, which pulls in `compat/regcomp_enhanced.c`, which references `REG_ENHANCED`, hence the build failure.
The `osx-gcc` job (CC=gcc-13) is unaffected because Homebrew GCC is configured to use Apple's SDK sysroot, so it still picks up Apple's `regex.h` which defines `REG_ENHANCED`. The `osx-meson` job is unaffected because Meson does a compile-time test for `REG_ENHANCED` (via `compiler.get_define`) and simply skips the feature when it is absent.
Work around this by setting `NO_REGEX` when `CC=clang` on Darwin, which makes the build use Git's bundled regex implementation instead of the system one. This sidesteps the missing `REG_ENHANCED` define entirely.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
config.mak.uname | 11 +++++++++++
1 file changed, 11 insertions(+)
Junio C Hamano
