On Wed Jul 15, 2026 at 8:49 PM UTC, Tristan Partin wrote: > On Wed Jul 15, 2026 at 8:44 PM UTC, Andrew Dunstan wrote: >> On Wed, Jul 15, 2026 at 12:30 PM Tristan Partin <[email protected]> wrote: >> >>> On Tue Jul 14, 2026 at 9:24 PM UTC, Andrew Dunstan wrote: >>> > Hi >>> > >>> > While setting up a Windows/MSVC buildfarm animal with NLS enabled, the >>> > meson 'tmp_install' and 'initdb_cache' setup tests failed immediately >>> > with exit status 1 and no stdout/stderr at all. >>> > >>> > With a little help from Claude, I (eventually) found this diagnosis and >>> > solution: >>> > >>> > The root cause turned out to be in meson itself, not in our meson.build. >>> > On Windows, determine_windows_extra_paths() in >>> > mesonbuild/backend/backends.py builds a test's PATH by walking every >>> > target passed via that test's 'depends:' kwarg (extra_bdeps) and adding >>> > each one's build directory unconditionally, with no check for whether >>> > the target actually produces a DLL. That's fine when 'depends:' lists a >>> > handful of real link dependencies, but the 'tmp_install' test depends on >>> > installed_targets, which includes nls_mo_targets - one custom_target per >>> > locale/domain of compiled .mo catalogs. With NLS enabled that's several >>> > hundred targets, none of them DLLs, none of them ever looked up via >>> > PATH, and each one still gets its own entry. >>> > >>> > In our case this inflated PATH to ~39000 characters across 584 entries >>> > (448 of them po/*/LC_MESSAGES directories), comfortably past practical >>> > Windows environment-variable/command-line length limits, which is why >>> > the test failed silently - the failure happens before the child process >>> > gets a chance to produce any output. >>> > >>> > I think this is arguably a meson bug (determine_windows_extra_paths() >>> > should filter extra_bdeps the same way it already filters a test >>> > executable's own link dependencies), but regardless of whether that >>> > gets fixed upstream, we can sidestep it on our end cheaply: depend on a >>> > trivial stamp custom_target instead of installed_targets directly. Its >>> > own 'depends:' still forces installed_targets to build first, so build >>> > ordering is unaffected, but since a custom_target is not a >>> > build.BuildTarget, meson doesn't recurse into its dependencies when >>> > computing the test PATH - it contributes at most one harmless directory >>> > instead of hundreds. >>> > >>> > I initially tried wrapping installed_targets in an alias_target() >>> > instead, which would avoid the recursion the same way, but test()'s >>> > 'depends:' kwarg is typechecked to only accept >>> > BuildTarget | CustomTarget | CustomTargetIndex and rejects AliasTarget >>> > outright: >>> > >>> > meson.build:NNNN:0: ERROR: test keyword argument 'depends' was of >>> > type array[AliasTarget] but should have been type >>> > array[BuildTarget | CustomTarget | CustomTargetIndex] >>> > >>> > The attached patch uses a custom_target instead, which satisfies that >>> > type check. >>> > >>> > Tested on Windows/MSVC (meson 1.11.1), building with -Dnls=enabled: >>> > >>> > before: tmp_install test PATH = 39193 chars, 584 entries, 448 >>> > LC_MESSAGES - tmp_install and initdb_cache setup tests FAIL >>> > (exit status 1, no output) >>> > after: tmp_install test PATH = 2189 chars, 43 entries, 0 >>> > LC_MESSAGES - all three setup tests (tmp_install, >>> > install_test_files, initdb_cache) OK >>> > >>> > I did not attempt to fix the same class of problem for any other test >>> > in the tree - this patch only touches the one setup test that was >>> > actually failing for us. If there's interest, the same technique could >>> > presumably be applied wherever else a test's 'depends:' pulls in a >>> > large target list. >>> >>> Hey Andrew, >>> >>> I took some time to raise this issue with the Meson team in their >>> Matrix/IRC channel. I'll see if the discussion goes anywhere. >>> >>> As for the fix and the results, they look good to me. I couldn't >>> identify any other problems where this could be an issue, so this seems >>> like a one-off. Did you notice any other problems? I only noticed >>> installed_targets depended on in tmp_install and install-quiet. >>> >> >> >> I should have mentioned that I raised an issue at < >> https://github.com/mesonbuild/meson/issues/16010> > > Thanks! Currently discussing potential solutions.
I posted a PR[0] to fix this. Just waiting on review. Thanks for your initial investigation. [0]: https://github.com/mesonbuild/meson/pull/16039 -- Tristan Partin PostgreSQL Contributors Team AWS (https://aws.amazon.com)
