--- a/mercurial/copies.py Tue Oct 21 17:09:37 2014 -0400
+++ b/mercurial/copies.py Thu Oct 16 06:35:06 2014 -0700
@@ -19,9 +19,15 @@
return f[:s]
def _findlimit(repo, a, b):
- """Find the earliest revision that's an ancestor of a or b but not both,
+ """
+ Find the last revision that needs to be checked to ensure that a full
+ transitive closure for file copies can be properly calculated.
+ Generally, this means finding the earliest revision number that's an
+ ancestor of a or b but not both, except when a or b is a direct descendent
+ of the other, in which case we can return the minimum revnum of a and b.
None if no such revision exists.
"""
+
# basic idea:
# - mark a and b with different sides
# - if a parent's children are all on the same side, the parent is
@@ -73,7 +79,29 @@
if not hascommonancestor:
return None
- return limit
+
+ # Consider the following flow (see test-commit-amend.t under issue4405):
+ # 1/ File 'a0' committed
+ # 2/ File renamed from 'a0' to 'a1' in a new commit (call it 'a1')
+ # 3/ Move back to first commit
+ # 4/ Create a new commit via revert to contents of 'a1' (call it 'a1-amend')
+ # 5/ Rename file from 'a1' to 'a2' and commit --amend 'a1-msg'
+ #
+ # During the amend in step five, we will be in this state:
+ #
+ # @ 3 temporary amend commit for a1-amend
+ # |
+ # o 2 a1-amend
+ # |
+ # | o 1 a1
+ # |/
+ # o 0 a0
+ #
+ # When findlimit is called, a and b are revs 3 and 0, so limit will be 2,
+ # yet the filelog has the copy information in rev 1 and we will not look
+ # back far enough unless we also look at the a and b as candidates.
+ # This only occurs when a is a descendent of b or visa-versa.
+ return min(limit, a, b)
def _chain(src, dst, a, b):
'''chain two sets of copies a->b'''