changeset 42502:5ceb91136ebe

copies: avoid unnecessary copying of copy dict When storing copy information in the changesets, this patch speeds up hg debugpathcopies FENNEC_58_0_2_BUILD1 FIREFOX_59_0b8_BUILD2 from 11s to 5.9s. That command takes 6.2s when storing copy information in filelogs. Differential Revision: https://phab.mercurial-scm.org/D6421
author Martin von Zweigbergk <martinvonz@google.com>
date Thu, 18 Apr 2019 21:21:44 -0700
parents 35d674a3d5db
children c0b51449bf6b
files mercurial/copies.py
diffstat 1 files changed, 8 insertions(+), 2 deletions(-) [+]
line wrap: on
line diff
--- a/mercurial/copies.py	Thu Apr 18 21:22:14 2019 -0700
+++ b/mercurial/copies.py	Thu Apr 18 21:21:44 2019 -0700
@@ -297,7 +297,7 @@
         if r == b.rev():
             _filter(a, b, copies)
             return copies
-        for c in children[r]:
+        for i, c in enumerate(children[r]):
             childctx = repo[c]
             if r == childctx.p1().rev():
                 parent = 1
@@ -309,7 +309,13 @@
             if not match.always():
                 childcopies = {dst: src for dst, src in childcopies.items()
                                if match(dst)}
-            childcopies = _chain(copies, childcopies)
+            # Copy the dict only if later iterations will also need it
+            if i != len(children[r]) - 1:
+                copies = copies.copy()
+            if childcopies:
+                childcopies = _chain(copies, childcopies)
+            else:
+                childcopies = copies
             for f in childctx.filesremoved():
                 if f in childcopies:
                     del childcopies[f]