changeset 46184:cb8b2ee89a5d

copies: stop attempt to avoid extra dict copies around branching In the python code, we attempt to avoid unnecessary dict copies when gathering copy information. However that logic is wobbly and I keep running into case where independent branches affects each others. With the current code we can't ensure we are the only "user" of dict when dealing with merge. This caused havoc in the next series on tests I am about to introduce. So for now I am disabling the faulty optimisation. I believe we will need a dedicated overlay to deal with the "copy on write logic" to have something correct. I am also hoping to find time to build dedicated test case for this category of problem instead of relying on side effect in other tests. However for now I am focussing on another issue. Differential Revision: https://phab.mercurial-scm.org/D9608
author Pierre-Yves David <pierre-yves.david@octobus.net>
date Tue, 15 Dec 2020 00:29:29 +0100
parents ee63c1173c1b
children 5f00eb608957
files mercurial/copies.py
diffstat 1 files changed, 5 insertions(+), 8 deletions(-) [+]
line wrap: on
line diff
--- a/mercurial/copies.py	Mon Dec 14 02:03:36 2020 +0100
+++ b/mercurial/copies.py	Tue Dec 15 00:29:29 2020 +0100
@@ -383,9 +383,11 @@
 
                 if copies is None:
                     # this is a root
-                    copies = {}
-
-                newcopies = copies
+                    newcopies = copies = {}
+                elif remaining_children:
+                    newcopies = copies.copy()
+                else:
+                    newcopies = copies
                 # chain the data in the edge with the existing data
                 if changes is not None:
                     childcopies = {}
@@ -403,8 +405,6 @@
                             newcopies[dest] = (current_rev, source)
                         assert newcopies is not copies
                     if changes.removed:
-                        if newcopies is copies:
-                            newcopies = copies.copy()
                         for f in changes.removed:
                             if f in newcopies:
                                 if newcopies is copies:
@@ -417,9 +417,6 @@
                 # that child). See comment below for details.
                 if current_copies is None:
                     current_copies = newcopies
-                elif current_copies is newcopies:
-                    # nothing to merge:
-                    pass
                 else:
                     # we are the second parent to work on c, we need to merge our
                     # work with the other.