rust-revlog: fix RevlogEntry.data() for NULL_REVISION
Before this change, the pseudo-entry returned by `Revlog.get_entry` for
`NULL_REVISION` would trigger errors in application code using it.
For example, this fixes a crash spotted with changelog data
while implementing RHGitaly: `Changelog.data_for_rev(-1)` was already
returning the pseudo content as expected, e.g., for `hg log`, but
`Changelog.entry_for_rev(-1).data()` would still crash with
"corrupted revlog, hash check failed for revision -1". There is
an added test for this scenario.
--- a/rust/hg-core/src/revlog/changelog.rs Thu Jul 06 11:43:26 2023 +0200
+++ b/rust/hg-core/src/revlog/changelog.rs Thu Jul 06 11:53:40 2023 +0200
@@ -336,6 +336,11 @@
changelog.data_for_rev(NULL_REVISION)?,
ChangelogRevisionData::null()
);
+ // same with the intermediate entry object
+ assert_eq!(
+ changelog.entry_for_rev(NULL_REVISION)?.data()?,
+ ChangelogRevisionData::null()
+ );
Ok(())
}
}
--- a/rust/hg-core/src/revlog/mod.rs Thu Jul 06 11:43:26 2023 +0200
+++ b/rust/hg-core/src/revlog/mod.rs Thu Jul 06 11:53:40 2023 +0200
@@ -562,6 +562,9 @@
pub fn data(&self) -> Result<Cow<'revlog, [u8]>, HgError> {
let data = self.rawdata()?;
+ if self.rev == NULL_REVISION {
+ return Ok(data);
+ }
if self.is_censored() {
return Err(HgError::CensoredNodeError);
}
@@ -688,6 +691,9 @@
revlog.rev_from_node(NULL_NODE.into()).unwrap(),
NULL_REVISION
);
+ let null_entry = revlog.get_entry(NULL_REVISION).ok().unwrap();
+ assert_eq!(null_entry.revision(), NULL_REVISION);
+ assert!(null_entry.data().unwrap().is_empty());
}
#[test]