Re: precise codeville-merge reference now available

Bram:

Congratulations on your progress on theory and implementation of precise 
Codeville merge.

You wrote:

> Second, there's some broken behavior with conflict cases. Actually,
> scratch that, conflict UI is broken in *all* systems out there,
...
> Since this is a problem which has been present in all version control
> systems to date, and nobody's really complained about it, I don't think
> it's urgent to fix it. Probably the best approach is to make a more
> verbose UI which actually explains these cases.

I didn't understand this issue, so I tried to reproduce it in darcs, but 
I couldn't cause anything obviously bad to happen.  I think that the reason 
I can't reproduce this problem is that darcs cannot "merge B and Y" without 
bringing in A (which B depends on) and X (which Y depends on).

Here is a bash transcript of my attempt (edited to remove my typing goofs).

Regards,

Zooko

MAIN yumyum:~$ mkdir darcstest
MAIN yumyum:~$ cd darcstest/
MAIN yumyum:~/darcstest$ mkdir r1
MAIN yumyum:~/darcstest$ cd r1
MAIN yumyum:~/darcstest/r1$ darcs init
MAIN yumyum:~/darcstest/r1$ cat > foofile
I am a happy file.
I like to eat ice cream and frogs.
Yummy yummy frogs.
MAIN yumyum:~/darcstest/r1$ darcs add foofile
MAIN yumyum:~/darcstest/r1$ darcs record --all --author="r1author" -m"init 
version of foofile"
Finished recording patch 'init version of foofile'
MAIN yumyum:~/darcstest/r1$ cat >> foofile
Actually, frogs are kind of yucky.
MAIN yumyum:~/darcstest/r1$ darcs record --all --author="r1author" -m"add line 
clarifying the statement about frogs"
Finished recording patch 'add line clarifying the statement about frogs'
MAIN yumyum:~/darcstest/r1$ cd ..
MAIN yumyum:~/darcstest$ mkdir r2
MAIN yumyum:~/darcstest$ cd r2/
MAIN yumyum:~/darcstest/r2$ darcs init
MAIN yumyum:~/darcstest/r2$ darcs pull -p'init' ../r1

Wed Jun 15 13:10:01 ADT 2005  r1author
  * init version of foofile
Shall I pull this patch? (1/1) [ynWvpxqadjk], or ? for help: y

Finished pulling and applying.
MAIN yumyum:~/darcstest/r2$ cat >> foofile
Actually, frogs are kind of yucky.
MAIN yumyum:~/darcstest/r2$ darcs record --all --author="r2author" -m"frogs?  
That's disgusting."
Finished recording patch 'frogs?  That's disgusting.'
MAIN yumyum:~/darcstest/r2$ cd ..
MAIN yumyum:~/darcstest$ cd r1
MAIN yumyum:~/darcstest/r1$ cat foofile
I am a happy file.
I like to eat ice cream and frogs.
Yummy yummy frogs.
Actually, frogs are kind of yucky.
MAIN yumyum:~/darcstest/r1$ head -3 foofile  > tmp ; mv tmp foofile
MAIN yumyum:~/darcstest/r1$ darcs whatsnew
{
hunk ./foofile 4
-Actually, frogs are kind of yucky.
}
MAIN yumyum:~/darcstest/r1$ darcs record --all --author="r1author" -m"Remove 
mistaken retraction of declaration of love for tasty frogs."
Finished recording patch 'Remove mistaken retraction of declaration of love for 
tasty frogs.'
MAIN yumyum:~/darcstest/r1$ cd ../r2/
MAIN yumyum:~/darcstest/r2$ head -3 foofile  > tmp ; mv tmp foofile
MAIN yumyum:~/darcstest/r2$ darcs record --all --author="r2author" -m"Fine.  
I'm not going to make a big deal out of this."
Finished recording patch 'Fine.  I'm not going to make a big deal out of this.'
MAIN yumyum:~/darcstest/r2$ cd ..
MAIN yumyum:~/darcstest$ mkdir mergetwoadds
MAIN yumyum:~/darcstest$ cd mergetwoadds/
MAIN yumyum:~/darcstest/mergetwoadds$ darcs init
MAIN yumyum:~/darcstest/mergetwoadds$ darcs pull ../r1

Wed Jun 15 13:10:43 ADT 2005  r1author
  * add line clarifying the statement about frogs
Shall I pull this patch? (1/2) [ynWvpxqadjk], or ? for help: y

Wed Jun 15 13:13:19 ADT 2005  r1author
  * Remove mistaken retraction of declaration of love for tasty frogs.
Shall I pull this patch? (2/2) [ynWvpxqadjk], or ? for help: d
Finished pulling and applying.
MAIN yumyum:~/darcstest/mergetwoadds$ darcs pull ../r2

Wed Jun 15 13:12:14 ADT 2005  r2author
  * frogs?  That's disgusting.
Shall I pull this patch? (1/2) [ynWvpxqadjk], or ? for help: y

Wed Jun 15 13:13:38 ADT 2005  r2author
  * Fine.  I'm not going to make a big deal out of this.
Shall I pull this patch? (2/2) [ynWvpxqadjk], or ? for help: d
We have conflicts in the following files:
./foofile
Finished pulling and applying.
MAIN yumyum:~/darcstest/mergetwoadds$ darcs whatsnew
{
hunk ./foofile 4
+v v v v v v v
+Actually, frogs are kind of yucky.
+^ ^ ^ ^ ^ ^ ^
}
MAIN yumyum:~/darcstest/mergetwoadds$ vi foofile # Here I use vi to remove the 
"v v v v..." and "^ ^ ^ ^..." conflict marker lines
MAIN yumyum:~/darcstest/mergetwoadds$ darcs record 
--author="mergetwoaddsauthor" --all -m"Merge identical added lines."
Finished recording patch 'Merge identical added lines.'
MAIN yumyum:~/darcstest/mergetwoadds$ cd ..
MAIN yumyum:~/darcstest$ mkdir mergetwosubtracts
MAIN yumyum:~/darcstest$ cd mergetwosubtracts/
MAIN yumyum:~/darcstest/mergetwosubtracts$ darcs pull -a ../r1
Pulling from "../r1"...
Finished pulling and applying.
MAIN yumyum:~/darcstest/mergetwosubtracts$ darcs pull -a ../r2
Finished pulling and applying.
MAIN yumyum:~/darcstest/mergetwosubtracts$ darcs whatsnew   
No changes!
MAIN yumyum:~/darcstest/mergetwosubtracts$ # whoa.  I thought that the merge of 
two subtracts would be a null conflict, not a no-changes.
MAIN yumyum:~/darcstest/mergetwosubtracts$ cd ..
MAIN yumyum:~/darcstest$ mkdir mergemergedaddswithmergedsubtracts
MAIN yumyum:~/darcstest$ cd mergemergedaddswithmergedsubtracts/
MAIN yumyum:~/darcstest/mergemergedaddswithmergedsubtracts$ darcs init
MAIN yumyum:~/darcstest/mergemergedaddswithmergedsubtracts$ darcs pull -a 
../mergetwoadds/
Finished pulling and applying.
MAIN yumyum:~/darcstest/mergemergedaddswithmergedsubtracts$ darcs pull -a 
../mergetwosubtracts/
Finished pulling and applying.
MAIN yumyum:~/darcstest/mergemergedaddswithmergedsubtracts$ darcs whatsnew
No changes!
MAIN yumyum:~/darcstest/mergemergedaddswithmergedsubtracts$ cat foofile
I am a happy file.
I like to eat ice cream and frogs.
Yummy yummy frogs.
MAIN yumyum:~/darcstest/mergemergedaddswithmergedsubtracts$