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. -- Tristan Partin PostgreSQL Contributors Team AWS (https://aws.amazon.com)
