Weird incorrect merge - now actually with simple reproducer

[Max Bowsher]

I've managed to produce a small reproducer for the weird merge issue
I've mentioned on this list before. My sample branch looks like this:

> maxb at z61p:~/wc/bzr/mctest/trunk$ bzr log --line
> 3: Max Bowsher 2010-08-06 Eliminate tab character.
> 2: Max Bowsher 2010-08-06 Drop RejectedException.
> 1: Max Bowsher 2010-08-06 Base.

r1 adds a file

r2 looks like this:

> maxb at z61p:~/wc/bzr/mctest/trunk$ bzr di -c 2
> === modified file 'MergeIssue.java'
> --- MergeIssue.java	2010-08-06 00:53:13 +0000
> +++ MergeIssue.java	2010-08-06 00:54:24 +0000
> @@ -3,7 +3,7 @@
>  public class MergeIssue extends BaseClass {
>      
>      @Override
> -    public void filterDown(Message msg, Resources res) throws RejectedException, BreakoutException {
> +    public void filterDown(Message msg, Resources res) throws BreakoutException {
>              if(msg.getFlag(MessageFlag.SEEN)) {	/* Allow msg through if we've already processed it */
>                  return;
>              }

r3 looks like this (it changes a single tab character into four spaces):

> maxb at z61p:~/wc/bzr/mctest/trunk$ bzr di -c 3
> === modified file 'MergeIssue.java'
> --- MergeIssue.java	2010-08-06 00:54:24 +0000
> +++ MergeIssue.java	2010-08-06 00:55:28 +0000
> @@ -4,7 +4,7 @@
>      
>      @Override
>      public void filterDown(Message msg, Resources res) throws BreakoutException {
> -            if(msg.getFlag(MessageFlag.SEEN)) {	/* Allow msg through if we've already processed it */
> +            if(msg.getFlag(MessageFlag.SEEN)) {    /* Allow msg through if we've already processed it */
>                  return;
>              }
>  
> 


Now, the merge I'm doing is to branch r1 and then to try to cherrypick
r3 on top of that:

> maxb at z61p:~/wc/bzr/mctest$ bzr branch -r 1 trunk cpbranch
> Branched 1 revision(s).                                                                                       
> maxb at z61p:~/wc/bzr/mctest$ cd cpbranch/
> maxb at z61p:~/wc/bzr/mctest/cpbranch$ bzr merge -c 3 ../trunk
>  M  MergeIssue.java                                                                                           
> Text conflict in MergeIssue.java
> 1 conflicts encountered.                                                                                      

Now, the conflict is expected. What's wrong, is that the conflict
markers look like this:

> public class MergeIssue extends BaseClass {
>     
>     @Override
> <<<<<<< TREE
>     public void filterDown(Message msg, Resources res) throws RejectedException, BreakoutException {
>             if(msg.getFlag(MessageFlag.SEEN)) {	/* Allow msg through if we've already processed it */
> =======
>             if(msg.getFlag(MessageFlag.SEEN)) {    /* Allow msg through if we've already processed it */
> >>>>>>> MERGE-SOURCE
>                 return;
>             }
> 

*Observe that if I delete the 'TREE' section in its entirety and keep
the 'MERGE-SOURCE' section in its entirety, there is a line missing from
the result!*

That's a bug, right?

(The branch mentioned in the above is pushed at
lp:~maxb/bzr/odd-merge-reproducer.)

Max.

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