Ted's Mozilla Blog

Last week I managed to find myself a little bit of time for a project I had been meaning to get to: bzexport. bzexport is a Mercurial extension that allows you to attach patches from your Mercurial patch queue to bugzilla from the Mercurial command line. It’s the obvious companion to the qimportbz extension. You can read the README for details on installing and using the extension, but the short form is:

hg bzexport [REV] [BUG]

where REV is the name of a currently applied patch from your queue, and BUG is a bug number to attach it to. Of course, the extension is smarter than just that, and if you leave off those parameters it will default to working on the topmost patch in your queue, and it will attempt to deduce the bug number from the commit message in the patch. (Standard notation used at Mozilla should work, i.e. “bug 12345 – some text”, “b=12345 some text” etc.)

bzexport attempts to be clever and borrow your Bugzilla login cookies from your default Firefox profile so that you don’t have to provide authentication details. This does not currently work on the Mercurial shipped with MozillaBuild, so you’ll have to provide your username and password in your .hgrc as described in the README if you intend to use it under MozillaBuild’s hg.

bzexport relies on Gerv‘s excellent BzAPI, so hats off to Gerv for that! Also, patches for additional functionality are welcome.

I often find myself landing patches on our 1.9.2 and 1.9.1 branches, both of which are in Mercurial repositories. This generally involves getting a changeset from the mozilla-central repository into one of these repositories, and also amending the changeset message to include the name of the person who gave me approval to land. There was some discussion recently on how it’s kind of a pain to do that. I’ve cooked up an easy solution for my own needs, perhaps it will serve yours as well.

I use “hg transplant” to get changesets from one repository to another. This assumes that you have local clones of both the source repository (mozilla-central in this case) and the destination repository (mozilla-1.9.2 or 1.9.1, usually). Assuming you had both clones side-by-side in a directory, you could run the transplant command in the destination repository’s working directory like so (where xxx is the changeset identifier of the changeset you want transplanted, you can also specify more than one changeset):

hg transplant -s ../mozilla-central xxx

The transplant command conveniently includes a “–filter” option that will let you alter the commit message or patch while transplanting. This requires you to have some sort of script for transplant to run. Here’s what I’m using (on Linux):

#!/bin/sh

if test -n "$APPEND"; then
 echo " $APPEND" >> "$1";
else
 if test -n "$EDITOR"; then
 $EDITOR "$1";
 else
 editor "$1";
 fi
fi

Save this as “transplant.sh” somewhere (and ensure that it’s executable), then in your ~/.hgrc, add a section:

[transplant]
filter = /path/to/transplant.sh

Now, when you run “hg transplant”, by default it will open an editor to edit the commit message for each changeset, allowing you to add approval information. But, even better, transplant.sh will append the contents of the “APPEND” variable if set, so you can run transplant like so to quickly append approval information:

APPEND="a=someone" hg transplant -s ../mozilla-central xxx

I find that this saves me a bunch of time, so hopefully it’s useful to someone else!