Compilation on Windows fails with assert in generated_cases.c.h

[sergey-miryanov]

Bug report

Bug description:

Command line: .\PCBuild\build.bat -p x64 -d -r

  python.c
  python.vcxproj -> D:\Sources\_pythonish\cpython\PCbuild\amd64\python_d.exe
  Assertion failed: WITHIN_STACK_BOUNDS(), file D:\Sources\_pythonish\cpython\Python\generated_cases.c.h, line 11092
  
D:\Sources\_pythonish\cpython\PCbuild\python.vcxproj(134,5): warning MSB3073: The command "setlocal
D:\Sources\_pythonish\cpython\PCbuild\python.vcxproj(134,5): warning MSB3073: set PYTHONPATH=D:\Sources\_pythonish\cpython\Lib
D:\Sources\_pythonish\cpython\PCbuild\python.vcxproj(134,5): warning MSB3073: "D:\Sources\_pythonish\cpython\PCbuild\amd64\python_d.exe" "D:\Sources\_pythonish\cpython\PC\validate_ucrtbase.py" ucrtbased" exited with code 3.
  Wrote D:\Sources\_pythonish\cpython\PCbuild\amd64\LICENSE.txt
  WinMain.c
  pythonw.vcxproj -> D:\Sources\_pythonish\cpython\PCbuild\amd64\pythonw_d.exe

Build succeeded.

D:\Sources\_pythonish\cpython\PCbuild\python.vcxproj(134,5): warning MSB3073: The command "setlocal
D:\Sources\_pythonish\cpython\PCbuild\python.vcxproj(134,5): warning MSB3073: set PYTHONPATH=D:\Sources\_pythonish\cpython\Lib
D:\Sources\_pythonish\cpython\PCbuild\python.vcxproj(134,5): warning MSB3073: "D:\Sources\_pythonish\cpython\PCbuild\amd64\python_d.exe" "D:\Sources\_pythonish\cpython\PC\validate_ucrtbase.py" ucrtbased" exited with code 3.
    1 Warning(s)
    0 Error(s)

Time Elapsed 00:01:06.65

CPython versions tested on:

CPython main branch

Operating systems tested on:

Windows

Linked PRs

• gh-131987: Bump the magic number #131991

[sergey-miryanov]

It compiles fine without 053c285

ping @mpage

[mpage]

I can't reproduce the error that you're seeing when I build from a clean checkout of cpython at c2ac662f284b7c3f0701173f2467bf1e18aad2e2. I'm using:

• Windows Standard 2025
• Visual Studio Community 2022
• .\PCBuild\build.bat -p x64 -d -r

[Fidget-Spinner]

@mpage I think we might've forgotten to bump the pycore magic number in that PR. So the OP might be loading stale bytecode.

[mpage]

I think we might've forgotten to bump the pycore magic number in that PR. So the OP might be loading stale bytecode.

Ugh, I thought I did that. Maybe it got blown away in a merge. That's probably what's happening. Thanks!

[sergey-miryanov]

Thanks for quick fix!