issue6528: add a config option to control the fixing on the fly

This will allow people who know to be safe to avoid any performance overhead
(and other potential issue).

Differential Revision: https://phab.mercurial-scm.org/D11271

mercurial/configitems.py

@@ -1892,6 +1892,11 coreconfigitem(
     default=True,
     alias=[(b'format', b'aggressivemergedeltas')],
 )
+coreconfigitem(
+    b'storage',
+    b'revlog.issue6528.fix-incoming',
+    default=True,
+)
 # experimental as long as rust is experimental (or a C version is implemented)
 coreconfigitem(
     b'storage',

mercurial/filelog.py

@@ -38,6 +38,8 class filelog(object):
         # Used by LFS.
         self._revlog.filename = path
         self.nullid = self._revlog.nullid
+        opts = opener.options
+        self._fix_issue6528 = opts.get(b'issue6528.fix-incoming', True)
 
     def __len__(self):
         return len(self._revlog)
@@ -160,7 +162,8 class filelog(object):
 
         with self._revlog._writing(transaction):
 
-            deltas = rewrite.filter_delta_issue6528(self._revlog, deltas)
+            if self._fix_issue6528:
+                deltas = rewrite.filter_delta_issue6528(self._revlog, deltas)
 
             return self._revlog.addgroup(
                 deltas,

mercurial/helptext/config.txt

@@ -2043,6 +2043,21 Alias definitions for revsets. See :hg:`
 Control the strategy Mercurial uses internally to store history. Options in this
 category impact performance and repository size.
 
+``revlog.issue6528.fix-incoming``
+    Version 5.8 of Mercurial had a bug leading to altering the parent of file
+    revision with copy information (or any other metadata) on exchange. This
+    leads to the copy metadata to be overlooked by various internal logic. The
+    issue was fixed in Mercurial 5.8.1.
+    (See https://bz.mercurial-scm.org/show_bug.cgi?id=6528 for details)
+
+    As a result Mercurial is now checking and fixing incoming file revisions to
+    make sure there parents are in the right order. This behavior can be
+    disabled by setting this option to `no`. This apply to revisions added
+    through push, pull, clone and unbundle.
+
+    To fix affected revisions that already exist within the repository, one can
+    use :hg:`debug-repair-issue-6528`.
+
 ``revlog.optimize-delta-parent-choice``
     When storing a merge revision, both parents will be equally considered as
     a possible delta base. This results in better delta selection and improved

mercurial/localrepo.py

@@ -1043,6 +1043,9 def resolverevlogstorevfsoptions(ui, req
     )
     options[b'deltabothparents'] = deltabothparents
 
+    issue6528 = ui.configbool(b'storage', b'revlog.issue6528.fix-incoming')
+    options[b'issue6528.fix-incoming'] = issue6528
+
     lazydelta = ui.configbool(b'storage', b'revlog.reuse-external-delta')
     lazydeltabase = False
     if lazydelta:

tests/test-issue6528.t

@@ -524,3 +524,104 And that the repair command does not fin
   no affected revisions were found
 
   $ cd ..
+
+A config option can disable the fixing of the bad bundle on the fly
+-------------------------------------------------------------------
+
+
+
+from a v1 bundle
+~~~~~~~~~~~~~~~~
+
+  $ hg debugbundle  --spec "$TESTDIR"/bundles/issue6528.hg-v1
+  bzip2-v1
+
+  $ hg init unbundle-v1-no-fix
+  $ cd unbundle-v1-no-fix
+
+  $ hg unbundle "$TESTDIR"/bundles/issue6528.hg-v1 --config storage.revlog.issue6528.fix-incoming=no
+  adding changesets
+  adding manifests
+  adding file changes
+  added 8 changesets with 12 changes to 4 files
+  new changesets f5a5a568022f:3beabb508514 (8 drafts)
+  (run 'hg update' to get a working copy)
+
+Check that revision were not fixed on the fly
+
+  $ hg debugrevlogindex b.txt
+     rev linkrev nodeid       p1           p2
+       0       2 05b806ebe5ea 000000000000 000000000000
+       1       3 a58b36ad6b65 05b806ebe5ea 000000000000
+       2       6 216a5fe8b8ed 000000000000 000000000000
+       3       7 ea4f2f2463cc 216a5fe8b8ed 000000000000
+
+  $ hg debugrevlogindex D.txt
+     rev linkrev nodeid       p1           p2
+       0       6 2a8d3833f2fb 000000000000 000000000000
+       1       7 2a80419dfc31 2a8d3833f2fb 000000000000
+
+That we do see the symptoms of the bug
+
+  $ hg up -- -1
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg status
+  M D.txt (?)
+  M b.txt (?)
+
+And that the repair command find issue to fix.
+
+  $ hg debug-repair-issue6528 --dry-run
+  found affected revision 1 for filelog 'data/D.txt.i'
+  found affected revision 1 for filelog 'data/b.txt.i'
+  found affected revision 3 for filelog 'data/b.txt.i'
+
+  $ cd ..
+
+from a v2 bundle
+~~~~~~~~~~~~~~~~
+
+  $ hg debugbundle --spec "$TESTDIR"/bundles/issue6528.hg-v2
+  bzip2-v2
+
+  $ hg init unbundle-v2-no-fix
+  $ cd unbundle-v2-no-fix
+
+  $ hg unbundle "$TESTDIR"/bundles/issue6528.hg-v2 --config storage.revlog.issue6528.fix-incoming=no
+  adding changesets
+  adding manifests
+  adding file changes
+  added 8 changesets with 12 changes to 4 files
+  new changesets f5a5a568022f:3beabb508514 (8 drafts)
+  (run 'hg update' to get a working copy)
+
+Check that revision were not fixed on the fly
+
+  $ hg debugrevlogindex b.txt
+     rev linkrev nodeid       p1           p2
+       0       2 05b806ebe5ea 000000000000 000000000000
+       1       3 a58b36ad6b65 05b806ebe5ea 000000000000
+       2       6 216a5fe8b8ed 000000000000 000000000000
+       3       7 ea4f2f2463cc 216a5fe8b8ed 000000000000
+
+  $ hg debugrevlogindex D.txt
+     rev linkrev nodeid       p1           p2
+       0       6 2a8d3833f2fb 000000000000 000000000000
+       1       7 2a80419dfc31 2a8d3833f2fb 000000000000
+
+That we do see the symptoms of the bug
+
+  $ hg up -- -1
+  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ hg status
+  M D.txt (?)
+  M b.txt (?)
+
+And that the repair command find issue to fix.
+
+  $ hg debug-repair-issue6528 --dry-run
+  found affected revision 1 for filelog 'data/D.txt.i'
+  found affected revision 1 for filelog 'data/b.txt.i'
+  found affected revision 3 for filelog 'data/b.txt.i'
+
+  $ cd ..