diff mercurial/copies.py @ 46408:e948ad0dcbe2

copies: add an devel option to trace all files

Filelog based copy tracing only trace copy for file that have been added. This
is a trade off between skipping some rare copy case in exchange for avoiding
atrocious-to-the-point-of-unusable performance.

The changeset centric copy tracing does not need this trade off and naturally
trace all copy, include the one involving non-new files.

In order to ease the comparison from both algorithm, we add a small devel option
to trace copy for all files in the target revisions.

Differential Revision: https://phab.mercurial-scm.org/D9796

--- a/mercurial/copies.py	Thu Jan 28 15:26:33 2021 +0100
+++ b/mercurial/copies.py	Sat Jan 16 00:03:18 2021 +0100
@@ -152,13 +152,21 @@
     if b.p1() == a and b.p2().node() == nullid:
         filesmatcher = matchmod.exact(b.files())
         forwardmissingmatch = matchmod.intersectmatchers(match, filesmatcher)
-    missing = _computeforwardmissing(a, b, match=forwardmissingmatch)
+    if repo.ui.configbool(b'devel', b'copy-tracing.trace-all-files'):
+        missing = list(b.walk(match))
+        # _computeforwardmissing(a, b, match=forwardmissingmatch)
+        if debug:
+            dbg(b'debug.copies:      searching all files: %d\n' % len(missing))
+    else:
+        missing = _computeforwardmissing(a, b, match=forwardmissingmatch)
+        if debug:
+            dbg(
+                b'debug.copies:      missing files to search: %d\n'
+                % len(missing)
+            )
 
     ancestrycontext = a._repo.changelog.ancestors([b.rev()], inclusive=True)
 
-    if debug:
-        dbg(b'debug.copies:      missing files to search: %d\n' % len(missing))
-
     for f in sorted(missing):
         if debug:
             dbg(b'debug.copies:        tracing file: %s\n' % f)