rhg: fix a crash on non-generaldelta revlogs
Differential Revision: https://phab.mercurial-scm.org/D11882
--- a/rust/hg-core/src/revlog/index.rs Tue Dec 07 18:12:13 2021 +0000
+++ b/rust/hg-core/src/revlog/index.rs Tue Dec 07 18:57:43 2021 +0000
@@ -84,6 +84,7 @@
/// Offsets of starts of index blocks.
/// Only needed when the index is interleaved with data.
offsets: Option<Vec<usize>>,
+ uses_generaldelta: bool,
}
impl Index {
@@ -100,6 +101,11 @@
return Err(HgError::corrupted("unsupported revlog version"));
}
+ // This is only correct because we know version is REVLOGV1.
+ // In v2 we always use generaldelta, while in v0 we never use
+ // generaldelta. Similar for [is_inline] (it's only used in v1).
+ let uses_generaldelta = header.format_flags().uses_generaldelta();
+
if header.format_flags().is_inline() {
let mut offset: usize = 0;
let mut offsets = Vec::new();
@@ -119,6 +125,7 @@
Ok(Self {
bytes,
offsets: Some(offsets),
+ uses_generaldelta,
})
} else {
Err(HgError::corrupted("unexpected inline revlog length")
@@ -128,10 +135,15 @@
Ok(Self {
bytes,
offsets: None,
+ uses_generaldelta,
})
}
}
+ pub fn uses_generaldelta(&self) -> bool {
+ self.uses_generaldelta
+ }
+
/// Value of the inline flag.
pub fn is_inline(&self) -> bool {
self.offsets.is_some()
@@ -259,7 +271,7 @@
}
/// Return the revision upon which the data has been derived.
- pub fn base_revision(&self) -> Revision {
+ pub fn base_revision_or_base_of_delta_chain(&self) -> Revision {
// TODO Maybe return an Option when base_revision == rev?
// Requires to add rev to IndexEntry
@@ -297,7 +309,7 @@
offset: usize,
compressed_len: usize,
uncompressed_len: usize,
- base_revision: Revision,
+ base_revision_or_base_of_delta_chain: Revision,
}
#[cfg(test)]
@@ -311,7 +323,7 @@
offset: 0,
compressed_len: 0,
uncompressed_len: 0,
- base_revision: 0,
+ base_revision_or_base_of_delta_chain: 0,
}
}
@@ -350,8 +362,11 @@
self
}
- pub fn with_base_revision(&mut self, value: Revision) -> &mut Self {
- self.base_revision = value;
+ pub fn with_base_revision_or_base_of_delta_chain(
+ &mut self,
+ value: Revision,
+ ) -> &mut Self {
+ self.base_revision_or_base_of_delta_chain = value;
self
}
@@ -374,7 +389,9 @@
bytes.extend(&[0u8; 2]); // Revision flags.
bytes.extend(&(self.compressed_len as u32).to_be_bytes());
bytes.extend(&(self.uncompressed_len as u32).to_be_bytes());
- bytes.extend(&self.base_revision.to_be_bytes());
+ bytes.extend(
+ &self.base_revision_or_base_of_delta_chain.to_be_bytes(),
+ );
bytes
}
}
@@ -480,14 +497,16 @@
}
#[test]
- fn test_base_revision() {
- let bytes = IndexEntryBuilder::new().with_base_revision(1).build();
+ fn test_base_revision_or_base_of_delta_chain() {
+ let bytes = IndexEntryBuilder::new()
+ .with_base_revision_or_base_of_delta_chain(1)
+ .build();
let entry = IndexEntry {
bytes: &bytes,
offset_override: None,
};
- assert_eq!(entry.base_revision(), 1)
+ assert_eq!(entry.base_revision_or_base_of_delta_chain(), 1)
}
#[test]
--- a/rust/hg-core/src/revlog/revlog.rs Tue Dec 07 18:12:13 2021 +0000
+++ b/rust/hg-core/src/revlog/revlog.rs Tue Dec 07 18:57:43 2021 +0000
@@ -191,11 +191,20 @@
// Todo return -> Cow
let mut entry = self.get_entry(rev)?;
let mut delta_chain = vec![];
- while let Some(base_rev) = entry.base_rev {
+
+ // The meaning of `base_rev_or_base_of_delta_chain` depends on
+ // generaldelta. See the doc on `ENTRY_DELTA_BASE` in
+ // `mercurial/revlogutils/constants.py` and the code in
+ // [_chaininfo] and in [index_deltachain].
+ let uses_generaldelta = self.index.uses_generaldelta();
+ while let Some(base_rev) = entry.base_rev_or_base_of_delta_chain {
+ let base_rev = if uses_generaldelta {
+ base_rev
+ } else {
+ entry.rev - 1
+ };
delta_chain.push(entry);
- entry = self
- .get_entry(base_rev)
- .map_err(|_| RevlogError::corrupted())?;
+ entry = self.get_entry_internal(base_rev)?;
}
// TODO do not look twice in the index
@@ -291,14 +300,26 @@
bytes: data,
compressed_len: index_entry.compressed_len(),
uncompressed_len: index_entry.uncompressed_len(),
- base_rev: if index_entry.base_revision() == rev {
+ base_rev_or_base_of_delta_chain: if index_entry
+ .base_revision_or_base_of_delta_chain()
+ == rev
+ {
None
} else {
- Some(index_entry.base_revision())
+ Some(index_entry.base_revision_or_base_of_delta_chain())
},
};
Ok(entry)
}
+
+ /// when resolving internal references within revlog, any errors
+ /// should be reported as corruption, instead of e.g. "invalid revision"
+ fn get_entry_internal(
+ &self,
+ rev: Revision,
+ ) -> Result<RevlogEntry, RevlogError> {
+ return self.get_entry(rev).map_err(|_| RevlogError::corrupted());
+ }
}
/// The revlog entry's bytes and the necessary informations to extract
@@ -309,7 +330,7 @@
bytes: &'a [u8],
compressed_len: usize,
uncompressed_len: usize,
- base_rev: Option<Revision>,
+ base_rev_or_base_of_delta_chain: Option<Revision>,
}
impl<'a> RevlogEntry<'a> {
@@ -375,7 +396,7 @@
/// Tell if the entry is a snapshot or a delta
/// (influences on decompression).
fn is_delta(&self) -> bool {
- self.base_rev.is_some()
+ self.base_rev_or_base_of_delta_chain.is_some()
}
}
--- a/tests/test-rhg-no-generaldelta.t Tue Dec 07 18:12:13 2021 +0000
+++ b/tests/test-rhg-no-generaldelta.t Tue Dec 07 18:57:43 2021 +0000
@@ -1,4 +1,3 @@
-
$ NO_FALLBACK="env RHG_ON_UNSUPPORTED=abort"
$ cat << EOF >> $HGRCPATH
@@ -21,9 +20,27 @@
1 0 prev
2 1 prev
-rhg breaks on non-generaldelta revlogs:
+rhg works on non-generaldelta revlogs:
- $ $NO_FALLBACK hg cat f -r . | f --sha256 --size
- abort: corrupted revlog (rhg !)
- size=0, sha256=e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (rhg !)
- size=58, sha256=0cf0386dd4813cc3b957ea790146627dfc0ec42ad3fcf47221b9842e4d5764c1 (no-rhg !)
+ $ $NO_FALLBACK hg cat f -r .
+ 1
+ 2
+ 3
+ 4
+ 5
+ 6
+ 7
+ 8
+ 9
+ 10
+ 11
+ 12
+ 13
+ 14
+ 15
+ 16
+ 17
+ 18
+ 19
+ 20
+ footer