cargo: invalid data in index - calculated checksum does not match expected; class=Index (10)

[dawn minnow]

has anyone seen this error before? i've never seen it and i don't know what could be causing it :(

PS C:\Users\jyn\src\rust> x c      
Building bootstrap
error: failed to determine package fingerprint for build script for bootstrap v0.0.0 (C:\Users\jyn\src\rust\src\bootstrap)

Caused by:
  failed to determine the most recently modified file in C:\Users\jyn\src\rust\src\bootstrap

Caused by:
  failed to determine list of files in C:\Users\jyn\src\rust\src\bootstrap

Caused by:
  failed to open git index at C:/Users/jyn/src/rust/.git/

Caused by:
  invalid data in index - calculated checksum does not match expected; class=Index (10)
failed to run: C:\Users\jyn\src\rust\build\x86_64-pc-windows-msvc\stage0\bin\cargo.exe build --manifest-path C:\Users\jyn\src\rust\src/bootstrap/Cargo.toml
Build completed unsuccessfully in 0:00:00

I wonder if libgit has some difference from git.exe? but idk why that would be

git.exe says everything is fine

PS C:\Users\jyn\src\rust> git status
On branch master
Your branch is up to date with 'origin/master'.

nothing to commit, working tree clean

setting $env:CARGO_NET_GIT_FETCH_WITH_CLI="1" does not seem to have helped 😞

CARGO_LOG=debug doesn't have much more info

[2023-04-25T14:42:07Z DEBUG cargo::core::compiler::context::compilation_files] Target filenames: [OutputFile { path: "C:\\Users\\jyn\\src\\rust\\build\\bootstrap\\debug\\deps\\libxz2-9f751de6437ff98e.rlib", hardlink: None, export_path: None, flavor: Linkable }, OutputFile { path: "C:\\Users\\jyn\\src\\rust\\build\\bootstrap\\debug\\deps\\libxz2-9f751de6437ff98e.rmeta", hardlink: None, export_path: None, flavor: Rmeta }]
[2023-04-25T14:42:07Z DEBUG cargo::core::compiler::fingerprint] fingerprint at: C:\Users\jyn\src\rust\build\bootstrap\debug\.fingerprint\bootstrap-981376b4624effc5\lib-bootstrap
[2023-04-25T14:42:07Z DEBUG cargo] exit_with_error; err=CliError { error: Some(failed to determine package fingerprint for build script for bootstrap v0.0.0 (C:\Users\jyn\src\rust\src\bootstrap)