--- a/tests/test-commit-amend.t Tue Oct 21 17:09:37 2014 -0400
+++ b/tests/test-commit-amend.t Thu Oct 16 06:35:06 2014 -0700
@@ -854,3 +854,61 @@
HG: changed foo
$ hg parents --template "{desc}\n"
editor should be invoked
+
+Check for issue4405
+-------------------
+
+Setup the repo with a file that gets moved in a second commit.
+ $ hg init repo
+ $ cd repo
+ $ touch a0
+ $ hg add a0
+ $ hg commit -m a0
+ $ hg mv a0 a1
+ $ hg commit -m a1
+ $ hg up -q 0
+ $ hg log -G --template '{rev} {desc}'
+ o 1 a1
+ |
+ @ 0 a0
+
+
+Now we branch the repro, but re-use the file contents, so we have a divergence
+in the file revlog topology and the changelog topology.
+ $ hg revert --rev 1 --all
+ removing a0
+ adding a1
+ $ hg ci -qm 'a1-amend'
+ $ hg log -G --template '{rev} {desc}'
+ @ 2 a1-amend
+ |
+ | o 1 a1
+ |/
+ o 0 a0
+
+
+The way mercurial does amends is to create a temporary commit (rev 3) and then
+fold the new and old commits together into another commit (rev 4). During this
+process, findlimit is called to check how far back to look for the transitive
+closure of file copy information, but due to the divergence of the filelog
+and changelog graph topologies, before findlimit was fixed, it returned a rev
+which was not far enough back in this case.
+ $ hg mv a1 a2
+ $ hg status --copies --rev 0
+ A a2
+ a0
+ R a0
+ $ hg ci --amend -q
+ $ hg log -G --template '{rev} {desc}'
+ @ 4 a1-amend
+ |
+ | o 1 a1
+ |/
+ o 0 a0
+
+
+Before the fix, the copy information was lost.
+ $ hg status --copies --rev 0
+ A a2
+ a0
+ R a0