[mooki000]

tests/test_wayland_libdecor_hint.py fails before it runs a case with Clang 23 (the readme: "LLVM 23 or newer reads
the play profile"; tests/run_all.py takes clang++ before g++): its C++ fixture is built with -Werror, and
Clang 23's -Wall now includes -Wunused-but-set-global.

Part of #2334.

harness.cpp:25:12: error: variable 'sdl_ready' set but not used [-Werror,-Wunused-but-set-global]

What changed

• The fixture declares the sdl_ready global that the function under test (hos_display_init from
  host/posix/display_sdl.c) sets, but never read it. The warning is right about the fixture: in the real file
  hos_display_owns_sdl reads it. The harness now prints it beside the init result (sdl2: init 1, ready 1,
  headless: init 0, ready 0). No warning is switched off.

How it was tested

Linux (Arch):

• Clang 23.1.3: fails on main with the error above; passes with the change (3 cases, 0 failed).
• GCC 16.2.1: passes before and after.
• -Wunused-but-set-global comes with -Wall in Clang 23 (a three-line file whose global is only written: warned with
  -Wall, not with -Wextra alone).
• python -I -B tests/run_all.py on main 49f75dc with this change (2026-11-11, Clang 23 as clang++, load about 70
  to 140): 362 passed, 2 failed, 10 skipped; tests/test_wayland_libdecor_hint.py passes. tests/test_updater_asset_digest.py
  fails on main as well on this machine (only a .NET 10 SDK; a pull request of its own). tests/test_bake_skeleton.py
  failed when one of its compiler processes ended with no output under that load; run alone afterwards it passes (9
  tests, 110 s).

Not tested

• CI's Clang (Ubuntu 24.04's) was not run here; the change only adds a read, which no compiler warns about.
• The check is skipped on Windows (RUN_ALL_SKIP), as before.

Assisted-by: Claude Opus 5.5
Co-Authored-By: Claude Opus 5.5 noreply@anthropic.com

[mooki000]

Rebased onto main b29967bf so the workflows run here: they had waited for an approval on the old head, and main's game-free tests are green again since #2380. The patch is unchanged (git range-diff: the commit is equal), and its test passes on the new base.

[Joey-Magnus]

Thanks for tracking this down with a real Clang 23 run. The diagnosis was right, but main already fixed the same warning a different way, so this PR is no longer needed.

question tests/test_wayland_libdecor_hint.py:42: #2171 (b5d6793, merged 2026-11-11 11:57) added int hos_display_owns_sdl(void) { return sdl_ready; } to the harness. Its commit message says "a one-line display-fixture declaration fixes an upstream Clang 23 unused-state warning". The global now has a reader, so -Wunused-but-set-global no longer fires on main. Your test run was on 49f75dc, which predates #2171. The rebase onto b29967b picked #2171 up without a conflict, which is why the diff still looks valid. On the current head, the extra sdl_ready in the printf (line 51) is a second read of a global that is already used, and the comment beside it gives a reason that no longer applies. Could you confirm with your Clang 23 that main passes without this change? If it does, I'd close this as superseded by #2171 (and maybe note that on #2334).

The two red CI jobs have nothing to do with this change. Windows part 1/2 fails in tests/test_native_astc_texture_count.py, and the appimage job timed out on a network download while installing system packages.

[Joey-Magnus]

I think #2171 already covers this: main's tests/test_wayland_libdecor_hint.py:42 has int hos_display_owns_sdl(void) { return sdl_ready; }, so the global already has a reader. This would add a redundant one, so it can probably be closed.

[mooki000]

Confirmed on clean main 940eb9ef with Clang 23.1.3: wayland libdecor hint: 3 cases, 0 failed (SDL2, SDL3 and headless). #2171’s hos_display_owns_sdl() already reads the state, so this PR’s extra printf read is redundant. Closing as superseded; thanks for catching it.