VS 2026's ARM64 code generator needs about 27 GB for
_PyUnicode_ToNumeric, a switch with 1951 cases in
Objects/unicodetype_db.h; the same file takes under 1 GB on x64. The
16 GB CI runner has an 18.9 GB commit limit and only gets through when
Windows grows the pagefile on the temp disk in time, so cold arm64
dependency builds fail at random with C1002 "compiler is out of heap
space". build_release_vs.bat returns 0 on failure, so the job still
reports success and the incomplete dependencies are cached.
A property sheet compiles that one file with optimisation off on arm64;
the rest stays whole-program optimised and x64 is unchanged.
MSBuild reads it from PCbuild/msbuild.rsp, which is now written at
configure time and copied in, so a checkout path with spaces works too.
git config wrote core.autocrlf into the repository git init creates in the
extracted CPython source. Nothing outside deps/build reads that repository, so
the setting was already contained.
-c applies the override to the one invocation instead, so no repository config is
written at all. It cannot reuse PATCH_CMD, so the shared flags are spelled out here.
git apply inherits the caller's configuration, so under core.autocrlf=input it
rewrites the patched PCbuild/find_python.bat to LF. cmd.exe cannot resolve goto
labels in an LF batch file, so CPython's build fails with "The system cannot
find the batch label specified - begin_search" and then "Cannot locate
python.exe on PATH or as PYTHON variable".
git init already runs in the extracted source, so setting core.autocrlf on the
repository it creates is enough, without touching the shared PATCH_CMD.
Kris Austin