add no-new-root check to josh pull

This commit is contained in:
Ralf Jung 2024-04-27 09:02:07 +02:00
parent 47a901b9bf
commit b4ad65b394

View file

@ -95,6 +95,14 @@ impl flags::RustcPull {
if !cmd!(sh, "git status --untracked-files=no --porcelain").read()?.is_empty() {
bail!("working directory must be clean before running `cargo xtask pull`");
}
// This should not add any new root commits. So count those before and after merging.
let num_roots = || -> anyhow::Result<u32> {
Ok(cmd!(sh, "git rev-list HEAD --max-parents=0 --count")
.read()
.context("failed to determine the number of root commits")?
.parse::<u32>()?)
};
let num_roots_before = num_roots()?;
// Make sure josh is running.
let josh = start_josh()?;
@ -126,6 +134,11 @@ impl flags::RustcPull {
.run()
.context("FAILED to merge new commits, something went wrong")?;
// Check that the number of roots did not increase.
if num_roots()? != num_roots_before {
bail!("Josh created a new root commit. This is probably not the history you want.");
}
drop(josh);
Ok(())
}