commitctx: extract copy information encoding into extra into commit.py

The encoding of copy information into extra has multiple subcases and become
quite complicated (eg: empty list can be explicitly or implicitly stored for
example). In addition, it is niche experimental feature since as it affect the
hash, it is only suitable for user who don't mercurial for storage server side
(ie: Google).

Having this complexity part of the changelog will get in the way of further
cleanup. We could have to either move more of that logic into the changelog or
to move or extract more of the logic at the higher level. We take the second
approach and start gather logic in dedicated function in commit.py.

mercurial/changelog.py

@@ -561,43 +561,21 b' class changelog(revlog.revlog):'
                 )
         sortedfiles = sorted(files)
         sidedata = None
-        if extra is not None:
-            for name in (
-                b'p1copies',
-                b'p2copies',
-                b'filesadded',
-                b'filesremoved',
-            ):
-                extra.pop(name, None)
-        if p1copies is not None:
-            p1copies = metadata.encodecopies(sortedfiles, p1copies)
-        if p2copies is not None:
-            p2copies = metadata.encodecopies(sortedfiles, p2copies)
-        if filesadded is not None:
-            filesadded = metadata.encodefileindices(sortedfiles, filesadded)
-        if filesremoved is not None:
-            filesremoved = metadata.encodefileindices(sortedfiles, filesremoved)
-        if self._copiesstorage == b'extra':
-            extrasentries = p1copies, p2copies, filesadded, filesremoved
-            if extra is None and any(x is not None for x in extrasentries):
-                extra = {}
-            if p1copies is not None:
-                extra[b'p1copies'] = p1copies
-            if p2copies is not None:
-                extra[b'p2copies'] = p2copies
-            if filesadded is not None:
-                extra[b'filesadded'] = filesadded
-            if filesremoved is not None:
-                extra[b'filesremoved'] = filesremoved
-        elif self._copiesstorage == b'changeset-sidedata':
+        if self._copiesstorage == b'changeset-sidedata':
             sidedata = {}
             if p1copies:
+                p1copies = metadata.encodecopies(sortedfiles, p1copies)
                 sidedata[sidedatamod.SD_P1COPIES] = p1copies
             if p2copies:
+                p2copies = metadata.encodecopies(sortedfiles, p2copies)
                 sidedata[sidedatamod.SD_P2COPIES] = p2copies
             if filesadded:
+                filesadded = metadata.encodefileindices(sortedfiles, filesadded)
                 sidedata[sidedatamod.SD_FILESADDED] = filesadded
             if filesremoved:
+                filesremoved = metadata.encodefileindices(
+                    sortedfiles, filesremoved
+                )
                 sidedata[sidedatamod.SD_FILESREMOVED] = filesremoved
             if not sidedata:
                 sidedata = None

mercurial/commit.py

@@ -69,6 +69,20 b' def commitctx(repo, ctx, error=False, or'
 
         extra = ctx.extra().copy()
 
+        files = sorted(files)
+        if extra is not None:
+            for name in (
+                b'p1copies',
+                b'p2copies',
+                b'filesadded',
+                b'filesremoved',
+            ):
+                extra.pop(name, None)
+        if repo.changelog._copiesstorage == b'extra':
+            extra = _extra_with_copies(
+                repo, extra, files, p1copies, p2copies, filesadded, filesremoved
+            )
+
         # update changelog
         repo.ui.note(_(b"committing changelog\n"))
         repo.changelog.delayupdate(tr)
@@ -407,3 +421,25 b' def _commit_manifest(tr, linkrev, ctx, m'
         mn = p1.manifestnode()
 
     return mn
+
+
+def _extra_with_copies(
+    repo, extra, files, p1copies, p2copies, filesadded, filesremoved
+):
+    """encode copy information into a `extra` dictionnary"""
+    extrasentries = p1copies, p2copies, filesadded, filesremoved
+    if extra is None and any(x is not None for x in extrasentries):
+        extra = {}
+    if p1copies is not None:
+        p1copies = metadata.encodecopies(files, p1copies)
+        extra[b'p1copies'] = p1copies
+    if p2copies is not None:
+        p2copies = metadata.encodecopies(files, p2copies)
+        extra[b'p2copies'] = p2copies
+    if filesadded is not None:
+        filesadded = metadata.encodefileindices(files, filesadded)
+        extra[b'filesadded'] = filesadded
+    if filesremoved is not None:
+        filesremoved = metadata.encodefileindices(files, filesremoved)
+        extra[b'filesremoved'] = filesremoved
+    return extra