Generate a Diff from a plugin

[John Arbash Meinel]

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Patrick Dobbs wrote:
> Hi,
> 
> We're using BZR with the "Decentralized with shared mainline" workflow.
> We want to integrate with our bug tracker (http://www.rap-x.com), but we
> need to be able to work offline. So we've created a Push plugin that
> loops through revisions in the current push, checks each revision for a
> bug id, and then posts this bug through a soap call:
> 
> def post_push_hook(push_result):
>    current_rev_no = push_result.old_revno
>    source = push_result.source_branch
>    while current_rev_no <= push_result.new_revno:
>        current_rev_id = source.get_rev_id(current_rev_no)
>        message = source.repository.get_revision(current_rev_id).message
>        bug_message = re.search("[\s|^](\#)(\d+)",message)
>        if bug_message:
>            bug_id = bug_message.group(2)
>            do_bugtracking_stuff(message,bug_id)
> 
> However, we'd like to be able to get a diff for each revision at the
> same time (the DIFF will be added to the bug tracker comment). I've dug
> a bit into bzrlib but have got confused with
> branches/trees/repositories/deltas and was hoping that someone more au
> fait with the api could advise me.
> 
> So, in summary, can anyone on this list advise me how, given a Branch
> object and two revision numbers, it is best to generate a diff (as a
> string)?
> 
> Thanks for any suggestions.
> 
> Patrick

There are easier and harder ways.

I'm pretty sure the easiest way is:

import cStringIO
from bzrlib import branch, diff

b = branch.Branch.open(path)
b.lock_read()

# Convert the revnos to revision ids
rev_id1 = b.revision_id_to_revno(revno1)
rev_id2 = b.revision_id_to_revno(revno2)

tree1, tree2 = b.repository.revision_trees([rev_id1, rev_id2])
out = cStringIO.StringIO()
diff.show_diff_trees(tree1, tree2, out, old_label='', new_label='')

out_as_str = out.getvalue()


John
=:->
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