At the moment, the sdk/loader/cuddlefish module loads sdk/system/xul-app in a hacky way in order to provide access to that module for a `incompatibility` function, which checks if a string like `"firefox > 33"` is compatible with the current application. In order for bug 1037235 to be fixed we need to either implement a similar hack in toolkit/loader, or we can move sdk/system/xul-app logic into a jsm. I like the latter version, because I will need this logic for bug 1040238 anyhow. If we develop a system where we can write jsm in the add-on sdk repo, which ship with Fx, then we should be able to get some performance wins too, since we can write whole modules, or portions that only instantiated once.

At the moment I'm using `resource://gre/modules/sdk/xul-app.js` but I'd like to use `resource://gre/modules/sdk/system/xul-app.js`, I'm not sure how to do this with the moz.build file atm though.

Comment on attachment 8459811 [details] Link to Github pull-request: https://github.com/mozilla/gecko-dev/pull/37 Aside from bikeshedding on naming this looks good. Unfortunately I think the only way of setting a custom location to put the module would be to add a moz.build into addon-sdk/source/modules/system. Not terribly scalable but doable.

(In reply to Dave Townsend [:mossop] from comment #2) > Comment on attachment 8459811 [details] > Link to Github pull-request: https://github.com/mozilla/gecko-dev/pull/37 > > Aside from bikeshedding on naming this looks good. Unfortunately I think the > only way of setting a custom location to put the module would be to add a > moz.build into addon-sdk/source/modules/system. Not terribly scalable but > doable. Hmm I made those changes, but the XulApp.js file doesn't seem to be included in Fx now, any idea what I've missed?

nvm I got it working now.

Commit pushed to master at https://github.com/mozilla/addon-sdk https://github.com/mozilla/addon-sdk/commit/69edfd7ac61fa88c3fc24bd60857409bbc626833 Bug 1040432 - Move sdk/system/xul-app to a jsm so that cuddlefish/toolkit loaders can access it easily. r=Mossop