threads / discuss / 43645

Re: More merge-recursive woes

Subject: Re: More merge-recursive woes

## tl;dr

3 messages between Dec 13, 2006 and Dec 13, 2006.

replies: 2people: 2as markdown or json

Shawn Pearce· Dec 13, 2006, 07:36 UTC · lore

More merge-recursive woes

Today I found two new bugs in git-merge-recursive. I'm still researching them, but I at least have a test case for one of the two:

Bug #1: If one branch renames a file which existed in the merge base, when we merge that change into a different branch the old version of the file is not deleted from the working directory. The attached test script shows this ("BAD: A still exists in working directory").

Bug #2: In that horrible repository that I have where I ran into the empty tree missing bug I now have a pair of commits which when merged together cause git-merge-recursive to go into an infinite loop, or least burn CPU for hours on end without doing squat. I have not been able to get enough data to even write a good analysis of it yet. I'll try to do that this week, as I cannot share the repository itself. It just happens to be two new commits along the same two branches however. :-(

Both bugs are appearing with current 'next' (8662d0ea).

After I eat something and weed through my inbox I may take a stab at the first one, if I haven't passed out on the couch. :-)

->->->->->->--t6024-merge-rename2.sh-->->->->->->->->- #!/bin/sh

test_description='Merge-recursive merging renames' . ./test-lib.sh

test_expect_success setup \ ' cat >A <<\EOF && a aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa b bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb c cccccccccccccccccccccccccccccccccccccccccccccccc d dddddddddddddddddddddddddddddddddddddddddddddddd e eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee f ffffffffffffffffffffffffffffffffffffffffffffffff g gggggggggggggggggggggggggggggggggggggggggggggggg h hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh i iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii j jjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj k kkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk l llllllllllllllllllllllllllllllllllllllllllllllll m mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm n nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn o oooooooooooooooooooooooooooooooooooooooooooooooo EOF

cat >M <<\EOF && A AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA B BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB C CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC D DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD E EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE F FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF G GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG H HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH I IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII J JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ K KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK L LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL M MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM N NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN O OOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO EOF

git add A M && git commit -m "initial has A and M" && git branch white && git branch red &&

git checkout white && sed -e "/^g /s/.*/g : white changes a line/" <A >B && sed -e "/^G /s/.*/G : colored branch changes a line/" <M >N && rm -f A M && git update-index --add --remove A B M N && git commit -m "white renames A->B, M->N" &&

git checkout red && echo created by red >R && git update-index --add R && git commit -m "red creates R" &&

git checkout master'
test_expect_success 'merge white into red' \
'
	git checkout -b red-white red &&
	git merge white &&
	git write-tree >/dev/null || {
		echo "BAD: merge did not complete"
		return 1
	}
	test -f B || {
		echo "BAD: B does not exist in working directory"
		return 1
	}
	test -f N || {
		echo "BAD: N does not exist in working directory"
		return 1
	}
	test -f R || {
		echo "BAD: R does not exist in working directory"
		return 1
	}
	test -f A && {
		echo "BAD: A still exists in working directory"
		return 1
	}
	test -f M && {
		echo "BAD: M still exists in working directory"
		return 1
	}
'
Johannes Schindelin· Dec 13, 2006, 14:28 UTC · re: Shawn Pearce · lore
Hi,
On Wed, 13 Dec 2006, Shawn Pearce wrote:
> Bug #1: If one branch renames a file which existed in the merge base, 
> when we merge that change into a different branch the old version of the 
> file is not deleted from the working directory.  The attached test 
> script shows this ("BAD: A still exists in working directory").
You miss a ":" at the end of the test script, BTW.

This bug is fixed by your patch, which makes remove_file() update the working directory in the last stage.

Show 8 quoted lines
> Bug #2: In that horrible repository that I have where I ran into the
> empty tree missing bug I now have a pair of commits which when merged
> together cause git-merge-recursive to go into an infinite loop,
> or least burn CPU for hours on end without doing squat.  I have
> not been able to get enough data to even write a good analysis
> of it yet.  I'll try to do that this week, as I cannot share the
> repository itself.  It just happens to be two new commits along
> the same two branches however.  :-(
Could you please send me the rev-list output for this test case?
Ciao,
Shawn Pearce· Dec 13, 2006, 20:34 UTC · re: Johannes Schindelin · lore
Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:
Show 11 quoted lines
> On Wed, 13 Dec 2006, Shawn Pearce wrote:
> 
> > Bug #1: If one branch renames a file which existed in the merge base, 
> > when we merge that change into a different branch the old version of the 
> > file is not deleted from the working directory.  The attached test 
> > script shows this ("BAD: A still exists in working directory").
> 
> You miss a ":" at the end of the test script, BTW.
>
> This bug is fixed by your patch, which makes remove_file() update the 
> working directory in the last stage.
Yes; and if you noticed this message got hung up in the email
system while I found the bug, fixed the bug, and replied to your
correction of the fix.  And I also fixed the test script along
the way.  Silly email systems holding messages.  *sigh*
 
Show 10 quoted lines
> > Bug #2: In that horrible repository that I have where I ran into the
> > empty tree missing bug I now have a pair of commits which when merged
> > together cause git-merge-recursive to go into an infinite loop,
> > or least burn CPU for hours on end without doing squat.  I have
> > not been able to get enough data to even write a good analysis
> > of it yet.  I'll try to do that this week, as I cannot share the
> > repository itself.  It just happens to be two new commits along
> > the same two branches however.  :-(
> 
> Could you please send me the rev-list output for this test case?

I'm actually going to go back in later tonight to try and figure this one out. Whatever data I get I'll be sure to include the rev-list --parents output from this case as well; unless I can craft a really small test case which causes the same infinite loop.

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