D6306: copies: write empty entries in changeset when also writing to filelog

martinvonz (Martin von Zweigbergk) phabricator at mercurial-scm.org
Tue Apr 23 16:32:46 EDT 2019

martinvonz created this revision.
Herald added a subscriber: mercurial-devel.
Herald added a reviewer: hg-reviewers.

  When writing to both changeset and filelog (during transition), we
  don't want the reader to waste time by falling back to reading from
  the filelog when there is no copy metadata. Let's write out empty copy
  metadata instead (the read path is already prepared for this
  case). Thanks to Greg for pointing this out.

  rHG Mercurial




diff --git a/tests/test-copies-in-changeset.t b/tests/test-copies-in-changeset.t
--- a/tests/test-copies-in-changeset.t
+++ b/tests/test-copies-in-changeset.t
@@ -101,6 +101,7 @@
   $ hg changesetcopies
   files: j
   p1copies: j\x00a (esc)
+  p2copies: 
   $ hg debugdata j 0
   \x01 (esc)
   copy: a
@@ -113,6 +114,14 @@
   a -> j
   $ hg showcopies --config experimental.copies.read-from=filelog-only
   a -> j
+The entries should be written to extras even if they're empty (so the client
+won't have to fall back to reading from filelogs)
+  $ echo x >> j
+  $ hg ci -m 'modify j' --config experimental.copies.write-to=compatibility
+  $ hg changesetcopies
+  files: j
+  p1copies: 
+  p2copies: 
 Test writing only to filelog
diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -2557,7 +2557,13 @@
         writecopiesto = self.ui.config('experimental', 'copies.write-to')
         writefilecopymeta = writecopiesto != 'changeset-only'
         p1copies, p2copies = None, None
-        if writecopiesto in ('changeset-only', 'compatibility'):
+        # If writing only to changeset extras, use None to indicate that
+        # no entry should be written. If writing to both, write an empty
+        # entry to prevent the reader from falling back to reading filelogs.
+        if writecopiesto == 'changeset-only':
+            p1copies = ctx.p1copies() or None
+            p2copies = ctx.p2copies() or None
+        elif writecopiesto == 'compatibility':
             p1copies = ctx.p1copies()
             p2copies = ctx.p2copies()
         with self.lock(), self.transaction("commit") as tr:
diff --git a/mercurial/changelog.py b/mercurial/changelog.py
--- a/mercurial/changelog.py
+++ b/mercurial/changelog.py
@@ -591,11 +591,11 @@
             elif branch in (".", "null", "tip"):
                 raise error.StorageError(_('the name \'%s\' is reserved')
                                          % branch)
-        if (p1copies or p2copies) and extra is None:
+        if (p1copies is not None or p2copies is not None) and extra is None:
             extra = {}
-        if p1copies:
+        if p1copies is not None:
             extra['p1copies'] = encodecopies(p1copies)
-        if p2copies:
+        if p2copies is not None:
             extra['p2copies'] = encodecopies(p2copies)
         if extra:

To: martinvonz, #hg-reviewers
Cc: mercurial-devel

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