fix(ci): use CMAKE_MSVC_DEBUG_INFORMATION_FORMAT=Embedded for sccache (documented fix)#432
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Per sccache documentation: cmake sets /Zi by default for MSVC, which writes debug info to a shared .pdb file. With Ninja + sccache + /MP running parallel cl.exe processes, this causes C1041 (PDB contention). Official fix (cmake >= 3.25): set CMAKE_POLICY_DEFAULT_CMP0141=NEW and CMAKE_MSVC_DEBUG_INFORMATION_FORMAT=Embedded, which instructs cmake to use /Z7 (debug info embedded in .obj) instead of /Zi for all targets. Replaces the manual /Z7 flags in CMAKE_CXX_FLAGS_RELEASE which only affected top-level targets and missed vendored subprojects.
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Root cause (properly researched this time)
Per the sccache README: cmake sets
/Ziby default for MSVC, which writes debug info to a shared.pdbfile. With Ninja + sccache +/MPall running parallelcl.exeprocesses, multiple processes race to write the same PDB →C1041.Official fix
For cmake ≥ 3.25 (we use ~3.31.0), the documented solution is:
This instructs cmake to pass
/Z7to all targets (including vendored subprojects like admesh), embedding debug info in each.objfile. No shared PDB → no contention.Previous attempt (
/Z7viaCMAKE_CXX_FLAGS_RELEASE) only affected top-level targets and missed subprojects that set their own flags (like admesh).