confusing error when original stacked branch becomes invalid later

[Michael Vogt]

I did the following:

$ bzr co lp:vmbuilder
$ cd vmbuilder
$ bzr merge lp:~mvo/vmbuilder/add-natty
bzr: ERROR: Not a branch: "bzr+ssh://bazaar.launchpad.net/~ubuntu-virt/vmbuilder/0.12/".

This is rather confusing as I have no idea where this references to 0.12 comes from.
Fortuantely jelmer in #bzr gave me the hint that the stacked branch 0.12 might have been
renamed or disappeared and this may cause the error.

The other interessting bit is that I pushed my local "add-natty" branch as lp:~mvo/vmbuilder/add-natty2:
$ bzr push lp:~mvo/vmbuilder/add-natty2
Using default stacking branch /~vmbuilder-dev/vmbuilder/0.12 at lp-57748368:///~mvo/vmbuilder
Created new stacked branch referring to /~vmbuilder-dev/vmbuilder/0.12.

*but* that branch I was able to merge into lp:vmbuilder.

[Michael Vogt (mvo)]

I just reproduced my steps in /tmp and I can easily trigger the error about the 0.12 branch with lp:~mvo/vmbuilder/add-natty. Please let me know if you need more info.

[Michael Vogt (mvo)]

Hm, actually it seems like I get this error now with most (all?) the branches on:
https://code.launchpad.net/vmbuilder

[Michael Vogt (mvo)]

Hm, there is:
https://launchpad.net/vmbuilder/0.12
and it says it points to lp:vmbuilder

[Aaron Bentley (abentley)]

While launchpad-code can try to reduce occurrences of missing stacked-on branches (and we already have bugs for that), the issue of the poor error message is not limited to Launchpad, and should be fixed in bzr.

[Jelmer Vernooij (jelmer)]

The issue seems to be that lp:vmbuilder is ~vmbuilder-dev/vmbuilder/0.12 rather than ~ubuntu-virt/vmbuilder/0.12

[Michael Vogt (mvo)]

Pointed out on #bzr:
<maxb> mvo: Note the difference between ~ubuntu-virt/vmbuilder/0.12 and ~vmbuilder-dev/vmbuilder/0.12

[Max Bowsher (maxb)]

The related (*not* duplicate) launchpad-code bug is bug 377519

[Michael Vogt (mvo)]

I added a bugtask against launchpad-code because I would like to see the stacked origin getting fixed. I can currently not merge older vmbuilder branches into trunk. Let me know if there is another/better way to request fixing this. I tried irc as well and I'm happy to submit a RT ticket if that is needed.

[Aaron Bentley (abentley)]

Michael, as I mentioned, we already have bugs for fixing the stacked on branch, so we don't need a new one. From the summary, this is a bug about a bad error message, which is a client-side issue.

[Aaron Bentley (abentley)]

If you would like us to manually fix a particular branch, ask on IRC or file a Question.