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Differential D11964

filelog: add a comment explaining a fast path in filerevisioncopied()
ClosedPublic

Authored by SimonSapin on Jan 6 2022, 1:56 PM.

Details

Reviewers
Alphare
Group Reviewers
hg-reviewers
Commits
rHG5026a0d37526: filelog: add a comment explaining a fast path in filerevisioncopied()

Diff Detail

Repository
rHG Mercurial
Lint
Automatic diff as part of commit; lint not applicable.
Unit
Automatic diff as part of commit; unit tests not applicable.

Revision Contents
Changeset List

PathPackages
Mmercurial/utils/storageutil.py (7 lines)

Diff 31617

mercurial/utils/storageutil.py

def filerevisioncopied(store, node): def filerevisioncopied(store, node):
"""Resolve file revision copy metadata. """Resolve file revision copy metadata.
Returns ``False`` if the file has no copy metadata. Otherwise a Returns ``False`` if the file has no copy metadata. Otherwise a
2-tuple of the source filename and node. 2-tuple of the source filename and node.
""" """
if store.parents(node)[0] != sha1nodeconstants.nullid: if store.parents(node)[0] != sha1nodeconstants.nullid:
# When creating a copy or move we set filelog parents to null,
# because contents are probably unrelated and making a delta
# would not be useful.
# Conversely, if filelog p1 is non-null we know
# there is no copy metadata.
# In the presence of merges, this reasoning becomes invalid
# if we reorder parents. See tests/test-issue6528.t.
return False return False
meta = parsemeta(store.revision(node))[0] meta = parsemeta(store.revision(node))[0]
# copy and copyrev occur in pairs. In rare cases due to old bugs, # copy and copyrev occur in pairs. In rare cases due to old bugs,
# one can occur without the other. So ensure both are present to flag # one can occur without the other. So ensure both are present to flag
# as a copy. # as a copy.
if meta and b'copy' in meta and b'copyrev' in meta: if meta and b'copy' in meta and b'copyrev' in meta: