rollback: explicitly skip dirstate rollback when applicable

instead of letting the transaction logic overwrite the dirstate and then
overwrite that overwrite with a backup. We simply do not restore the dirstate
related file during the _playback call.

This open the way to removing the last dirstate guard usage.

mercurial/localrepo.py

@@ -10,6 +10,7 b''
 import functools
 import os
 import random
+import re
 import sys
 import time
 import weakref
@@ -100,6 +101,8 b' release = lockmod.release'
 urlerr = util.urlerr
 urlreq = util.urlreq
 
+RE_SKIP_DIRSTATE_ROLLBACK = re.compile(b"^(dirstate|narrowspec.dirstate).*")
+
 # set of (path, vfs-location) tuples. vfs-location is:
 # - 'plain for vfs relative paths
 # - '' for svfs relative paths
@@ -2748,8 +2751,16 b' class localrepository:'
 
         self.destroying()
         vfsmap = {b'plain': self.vfs, b'': self.svfs}
+        skip_journal_pattern = None
+        if not parentgone:
+            skip_journal_pattern = RE_SKIP_DIRSTATE_ROLLBACK
         transaction.rollback(
-            self.svfs, vfsmap, b'undo', ui.warn, checkambigfiles=_cachedfiles
+            self.svfs,
+            vfsmap,
+            b'undo',
+            ui.warn,
+            checkambigfiles=_cachedfiles,
+            skip_journal_pattern=skip_journal_pattern,
         )
         bookmarksvfs = bookmarks.bookmarksvfs(self)
         if bookmarksvfs.exists(b'undo.bookmarks'):

mercurial/transaction.py

@@ -738,7 +738,14 b' BAD_VERSION_MSG = _('
 )
 
 
-def rollback(opener, vfsmap, file, report, checkambigfiles=None):
+def rollback(
+    opener,
+    vfsmap,
+    file,
+    report,
+    checkambigfiles=None,
+    skip_journal_pattern=None,
+):
     """Rolls back the transaction contained in the given file
 
     Reads the entries in the specified file, and the corresponding
@@ -783,6 +790,9 b' def rollback(opener, vfsmap, file, repor'
                         line = line[:-1]
                         l, f, b, c = line.split(b'\0')
                         backupentries.append((l, f, b, bool(c)))
+    if skip_journal_pattern is not None:
+        keep = lambda x: not skip_journal_pattern.match(x[1])
+        backupentries = [x for x in backupentries if keep(x)]
 
     _playback(
         file,