Two weeks ago changes landed in Mozilla to reduce the locations searched for a mozconfig to just $MOZCONFIG and $topsrcdir/.mozconfig. Previously a bunch of other weird places were searched, like $topsrcdir/mozconfig.sh and $topsrcdir/myconfig.sh and even some files in $HOME (!). This change made specifying build options more explicit, in line with build system policy to be “as explicit as possible”. Reducing complexity by killing off a bunch of truly odd configuration option locations was good. But I thought it went too far.

The changes also removed $topsrcdir/mozconfig. This location wasn’t nearly as bizarre as the others, and it was more explicit than $topsrcdir/.mozconfig: it appeared in directory listings and folder views. I wasn’t the only person who thought $topsrcdir/mozconfig should stay: the bug which reduced the mozconfig guesswork included rumblings from others wanting to keep support for $topsrcdir/mozconfig, and the blog post announcing the change included yet more.

I filed a bug to re-support $topsrcdir/mozconfig, and the patch has landed. $topsrcdir/.mozconfig and $topsrcdir/mozconfig (either but not both) now work again: use whichever name you like.