--- a/mercurial/revlogutils/rewrite.py Mon Aug 09 19:49:57 2021 -0400
+++ b/mercurial/revlogutils/rewrite.py Tue Jul 27 21:45:27 2021 +0200
@@ -7,6 +7,7 @@
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
+import binascii
import contextlib
import os
@@ -472,3 +473,224 @@
new_index_file.write(entry_bin)
revlog._docket.index_end = new_index_file.tell()
revlog._docket.data_end = new_data_file.tell()
+
+
+def _get_filename_from_filelog_index(path):
+ # Drop the extension and the `data/` prefix
+ path_part = path.rsplit(b'.', 1)[0].split(b'/', 1)
+ if len(path_part) < 2:
+ msg = _(b"cannot recognize filelog from filename: '%s'")
+ msg %= path
+ raise error.Abort(msg)
+
+ return path_part[1]
+
+
+def _filelog_from_filename(repo, path):
+ """Returns the filelog for the given `path`. Stolen from `engine.py`"""
+
+ from .. import filelog # avoid cycle
+
+ fl = filelog.filelog(repo.svfs, path)
+ return fl
+
+
+def _write_swapped_parents(repo, rl, rev, offset, fp):
+ """Swaps p1 and p2 and overwrites the revlog entry for `rev` in `fp`"""
+ from ..pure import parsers # avoid cycle
+
+ if repo._currentlock(repo._lockref) is None:
+ # Let's be paranoid about it
+ msg = "repo needs to be locked to rewrite parents"
+ raise error.ProgrammingError(msg)
+
+ index_format = parsers.IndexObject.index_format
+ entry = rl.index[rev]
+ new_entry = list(entry)
+ new_entry[5], new_entry[6] = entry[6], entry[5]
+ packed = index_format.pack(*new_entry[:8])
+ fp.seek(offset)
+ fp.write(packed)
+
+
+def _reorder_filelog_parents(repo, fl, to_fix):
+ """
+ Swaps p1 and p2 for all `to_fix` revisions of filelog `fl` and writes the
+ new version to disk, overwriting the old one with a rename.
+ """
+ from ..pure import parsers # avoid cycle
+
+ ui = repo.ui
+ assert len(to_fix) > 0
+ rl = fl._revlog
+ if rl._format_version != constants.REVLOGV1:
+ msg = "expected version 1 revlog, got version '%d'" % rl._format_version
+ raise error.ProgrammingError(msg)
+
+ index_file = rl._indexfile
+ new_file_path = index_file + b'.tmp-parents-fix'
+ repaired_msg = _(b"repaired revision %d of 'filelog %s'\n")
+
+ with ui.uninterruptible():
+ try:
+ util.copyfile(
+ rl.opener.join(index_file),
+ rl.opener.join(new_file_path),
+ checkambig=rl._checkambig,
+ )
+
+ with rl.opener(new_file_path, mode=b"r+") as fp:
+ if rl._inline:
+ index = parsers.InlinedIndexObject(fp.read())
+ for rev in fl.revs():
+ if rev in to_fix:
+ offset = index._calculate_index(rev)
+ _write_swapped_parents(repo, rl, rev, offset, fp)
+ ui.write(repaired_msg % (rev, index_file))
+ else:
+ index_format = parsers.IndexObject.index_format
+ for rev in to_fix:
+ offset = rev * index_format.size
+ _write_swapped_parents(repo, rl, rev, offset, fp)
+ ui.write(repaired_msg % (rev, index_file))
+
+ rl.opener.rename(new_file_path, index_file)
+ rl.clearcaches()
+ rl._loadindex()
+ finally:
+ util.tryunlink(new_file_path)
+
+
+def _is_revision_affected(ui, fl, filerev, path):
+ """Mercurial currently (5.9rc0) uses `p1 == nullrev and p2 != nullrev` as a
+ special meaning compared to the reverse in the context of filelog-based
+ copytracing. issue6528 exists because new code assumed that parent ordering
+ didn't matter, so this detects if the revision contains metadata (since
+ it's only used for filelog-based copytracing) and its parents are in the
+ "wrong" order."""
+ try:
+ raw_text = fl.rawdata(filerev)
+ except error.CensoredNodeError:
+ # We don't care about censored nodes as they never carry metadata
+ return False
+ has_meta = raw_text.startswith(b'\x01\n')
+ if has_meta:
+ (p1, p2) = fl.parentrevs(filerev)
+ if p1 != nullrev and p2 == nullrev:
+ return True
+ return False
+
+
+def _from_report(ui, repo, context, from_report, dry_run):
+ """
+ Fix the revisions given in the `from_report` file, but still checks if the
+ revisions are indeed affected to prevent an unfortunate cyclic situation
+ where we'd swap well-ordered parents again.
+
+ See the doc for `debug_fix_issue6528` for the format documentation.
+ """
+ ui.write(_(b"loading report file '%s'\n") % from_report)
+
+ with context(), open(from_report, mode='rb') as f:
+ for line in f.read().split(b'\n'):
+ if not line:
+ continue
+ filenodes, filename = line.split(b' ', 1)
+ fl = _filelog_from_filename(repo, filename)
+ to_fix = set(
+ fl.rev(binascii.unhexlify(n)) for n in filenodes.split(b',')
+ )
+ excluded = set()
+
+ for filerev in to_fix:
+ if _is_revision_affected(ui, fl, filerev, filename):
+ msg = b"found affected revision %d for filelog '%s'\n"
+ ui.warn(msg % (filerev, filename))
+ else:
+ msg = _(b"revision %s of file '%s' is not affected\n")
+ msg %= (binascii.hexlify(fl.node(filerev)), filename)
+ ui.warn(msg)
+ excluded.add(filerev)
+
+ to_fix = to_fix - excluded
+ if not to_fix:
+ msg = _(b"no affected revisions were found for '%s'\n")
+ ui.write(msg % filename)
+ continue
+ if not dry_run:
+ _reorder_filelog_parents(repo, fl, sorted(to_fix))
+
+
+def repair_issue6528(ui, repo, dry_run=False, to_report=None, from_report=None):
+ from .. import store # avoid cycle
+
+ @contextlib.contextmanager
+ def context():
+ if dry_run or to_report: # No need for locking
+ yield
+ else:
+ with repo.wlock(), repo.lock():
+ yield
+
+ if from_report:
+ return _from_report(ui, repo, context, from_report, dry_run)
+
+ report_entries = []
+
+ with context():
+ files = list(
+ (file_type, path)
+ for (file_type, path, _e, _s) in repo.store.datafiles()
+ if path.endswith(b'.i') and file_type & store.FILEFLAGS_FILELOG
+ )
+
+ progress = ui.makeprogress(
+ _(b"looking for affected revisions"),
+ unit=_(b"filelogs"),
+ total=len(files),
+ )
+ found_nothing = True
+
+ for file_type, path in files:
+ if (
+ not path.endswith(b'.i')
+ or not file_type & store.FILEFLAGS_FILELOG
+ ):
+ continue
+ progress.increment()
+ filename = _get_filename_from_filelog_index(path)
+ fl = _filelog_from_filename(repo, filename)
+
+ # Set of filerevs (or hex filenodes if `to_report`) that need fixing
+ to_fix = set()
+ for filerev in fl.revs():
+ # TODO speed up by looking at the start of the delta
+ # If it hasn't changed, it's not worth looking at the other revs
+ # in the same chain
+ affected = _is_revision_affected(ui, fl, filerev, path)
+ if affected:
+ msg = b"found affected revision %d for filelog '%s'\n"
+ ui.warn(msg % (filerev, path))
+ found_nothing = False
+ if not dry_run:
+ if to_report:
+ to_fix.add(binascii.hexlify(fl.node(filerev)))
+ else:
+ to_fix.add(filerev)
+
+ if to_fix:
+ to_fix = sorted(to_fix)
+ if to_report:
+ report_entries.append((filename, to_fix))
+ else:
+ _reorder_filelog_parents(repo, fl, to_fix)
+
+ if found_nothing:
+ ui.write(_(b"no affected revisions were found\n"))
+
+ if to_report and report_entries:
+ with open(to_report, mode="wb") as f:
+ for path, to_fix in report_entries:
+ f.write(b"%s %s\n" % (b",".join(to_fix), path))
+
+ progress.complete()