changeset 42486:35d674a3d5db

copies: don't filter out copy targets created on other side of merge commit If file X is copied to Y on one side of merge and the other side creates Y (no copy), we would not mark that as copy. In the changeset-centric pathcopies() version, that was done by checking if the copy target existed on the other branch. Even though merge commits are pretty uncommon, it still turned out to be too expensive to load the manifest of the parents of merge commits. In a repo of mozilla-unified converted to storing copies in changesets, about 2m30s of `hg debugpathcopies FIREFOX_BETA_59_END FIREFOX_BETA_60_BASE` is spent on this check of merge commits. I tried to think of a way of storing more information in the changesets in order to cheaply detect these cases, but I couldn't think of a solution. So this patch simply removes those checks. For reference, these extra copies are reported from the aforementioned command after this patch: browser/base/content/sanitize.js -> browser/modules/Sanitizer.jsm testing/mozbase/mozprocess/tests/process_normal_finish_python.ini -> testing/mozbase/mozprocess/tests/process_normal_finish.ini testing/mozbase/mozprocess/tests/process_waittimeout_python.ini -> testing/mozbase/mozprocess/tests/process_waittimeout.ini testing/mozbase/mozprocess/tests/process_waittimeout_10s_python.ini -> testing/mozbase/mozprocess/tests/process_waittimeout_10s.ini Since these copies were created on one side of some merge, it still seems reasonable to include them, so I'm not even sure it's worse than filelog pathcopies(), just different. Differential Revision: https://phab.mercurial-scm.org/D6420
author Martin von Zweigbergk <martinvonz@google.com>
date Thu, 18 Apr 2019 21:22:14 -0700
parents 4c39c99d9492
children 5ceb91136ebe
files mercurial/copies.py tests/test-copies.t
diffstat 2 files changed, 16 insertions(+), 16 deletions(-) [+]
line wrap: on
line diff
--- a/mercurial/copies.py	Thu Apr 18 00:40:53 2019 -0700
+++ b/mercurial/copies.py	Thu Apr 18 21:22:14 2019 -0700
@@ -276,27 +276,22 @@
             # We are tracing copies from both parents
             r, i2, copies2 = heapq.heappop(work)
             copies = {}
-            ctx = repo[r]
-            p1man, p2man = ctx.p1().manifest(), ctx.p2().manifest()
             allcopies = set(copies1) | set(copies2)
             # TODO: perhaps this filtering should be done as long as ctx
             # is merge, whether or not we're tracing from both parent.
             for dst in allcopies:
                 if not match(dst):
                     continue
-                if dst not in copies2:
-                    # Copied on p1 side: mark as copy from p1 side if it didn't
-                    # already exist on p2 side
-                    if dst not in p2man:
-                        copies[dst] = copies1[dst]
-                elif dst not in copies1:
-                    # Copied on p2 side: mark as copy from p2 side if it didn't
-                    # already exist on p1 side
-                    if dst not in p1man:
-                        copies[dst] = copies2[dst]
+                # Unlike when copies are stored in the filelog, we consider
+                # it a copy even if the destination already existed on the
+                # other branch. It's simply too expensive to check if the
+                # file existed in the manifest.
+                if dst in copies1:
+                    # If it was copied on the p1 side, mark it as copied from
+                    # that side, even if it was also copied on the p2 side.
+                    copies[dst] = copies1[dst]
                 else:
-                    # Copied on both sides: mark as copy from p1 side
-                    copies[dst] = copies1[dst]
+                    copies[dst] = copies2[dst]
         else:
             copies = copies1
         if r == b.rev():
--- a/tests/test-copies.t	Thu Apr 18 00:40:53 2019 -0700
+++ b/tests/test-copies.t	Thu Apr 18 21:22:14 2019 -0700
@@ -452,8 +452,9 @@
   y -> z
   $ hg debugpathcopies 1 3
 
-Create x and y, then rename x to z on one side of merge, and rename y to z and modify z on the
-other side.
+Create x and y, then rename x to z on one side of merge, and rename y to z and
+modify z on the other side. When storing copies in the changeset, we don't
+filter out copies whose target was created on the other side of the merge.
   $ newrepo
   $ echo x > x
   $ echo y > y
@@ -494,12 +495,16 @@
   o  0 add x and y
      x y
   $ hg debugpathcopies 1 4
+  y -> z (no-filelog !)
   $ hg debugpathcopies 2 4
+  x -> z (no-filelog !)
   $ hg debugpathcopies 0 4
   x -> z (filelog !)
   y -> z (compatibility !)
   $ hg debugpathcopies 1 5
+  y -> z (no-filelog !)
   $ hg debugpathcopies 2 5
+  x -> z (no-filelog !)
   $ hg debugpathcopies 0 5
   x -> z