Platform: FF17 win32

I am trying to modify modules/AddonUpdateChecker.jsm within omni.ja. No matter what I do I cannot get FF to take any notice of my modifications.

I have been through all the things suggested in various places on teh internetz:

  • every startupCache in sight
  • Enabled/disabled extensions to force reload of omni.ja
  • Even tried uninstall/reinstall of FF, modifying the jar before first run

I don't want to fall victim to the XY problem, so:

What I am really trying to do is implement this for the automated build process for my extension(s). Yes, I am aware that there are existing solutions to this, but I wish to implement it myself as the build system is highly customised.

I have now reached a point where FF is (in effect) saying that my signature is wrong. I suspect this is because my serialisation routine is wrong, and I can't work out where based on the documentation - so I would like to inspect the serialised string that FF is constructing on the client side for the comparison. This string is constructed and the signature is verified (via XPCOM) in modules/AddonUpdateChecker.jsm.

So, how can I get Firefox to pay attention to my modifications? Or is there an easier way to view this string?


Current Firefox versions have a cache inside omni.ja itself. If you remove the file jsloader/resource/gre/modules/AddonUpdateChecker.jsm from omni.ja then Firefox should start looking at your modified modules/AddonUpdateChecker.jsm instead. Additionally, you want to specify -purgecaches command line flag instead of hunting down startup caches.

Side-note: it is generally helpful to set extensions.logging.enabled to true when debugging extension installation issues, this will print lots of additional information to Error Console. Of course, I don't know whether this additional information will be sufficient in your particular case.

  • extensions.logging.enabled doesn't assist in this case, it simply enables the message that tells me that the signature is wrong - which is sort of what I would expect, since the serialised file is potentialy a few KBs and it's highly unlikely people would want to view it because most people will use official mozilla tools for this. Many thanks for your answer, it sounds like it's likely to solve the problem, I will test this afternoon and let you know how I get on.
    – DaveRandom
    Jan 7 '13 at 9:02
  • 1
    Re -purgecaches - I do this every startup anyway because I only ever use FF for debugging extensions, but I was starting to get desperate!
    – DaveRandom
    Jan 7 '13 at 9:40

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