Bug 1186409 is currently blocked on non-strict `this` boxing issues in some JSMs. At this point, we shouldn't be relying on non-strict-mode behavior, so it's probably time to just enforce strict mode on all JSM/component scripts.

Comment on attachment 8901988 [details] Bug 1394556: Part 1 - Fix strict mode errors in JSM scripts. https://reviewboard.mozilla.org/r/173402/#review178782 ::: services/common/kinto-offline-client.js:21 (Diff revision 1) > > /* > * This file is generated from kinto.js - do not modify directly. > */ > > +const global = this; This also needs to be fixed upstream. I'll file a separate PR for that.

Comment on attachment 8901988 [details] Bug 1394556: Part 1 - Fix strict mode errors in JSM scripts. https://reviewboard.mozilla.org/r/173402/#review179246 ::: testing/specialpowers/content/SpecialPowersObserver.jsm:258 (Diff revision 2) > } > let createdFiles = this._createdFiles; > try { > let promises = []; > aMessage.data.forEach(function(request) { > - const filePerms = 0666; // eslint-disable-line no-octal > + const filePerms = 0o666; // eslint-disable-line no-octal I think you can get rid of the eslint disable here now.

Comment on attachment 8901989 [details] Bug 1394556: Part 2 - Compile all JSM/module scripts in strict mode. https://reviewboard.mozilla.org/r/173404/#review179252

https://hg.mozilla.org/integration/mozilla-inbound/rev/3a804c720f13b46ba5604fd59904538b44546d23 Bug 1394556: Part 1 - Fix strict mode errors in JSM scripts. r=Mossop https://hg.mozilla.org/integration/mozilla-inbound/rev/0ab0630eec0c15b591b379454fe59344bac62290 Bug 1394556: Part 2 - Compile all JSM/module scripts in strict mode. r=Mossop

Jörg, there's a good chance this will affect Thunderbird. Look out for errors like "TypeError: this is null", "TypeError: setting a property that has only a getter", and "ReferenceError: assignment to undeclared variable"

Thanks for the heads-up, I love changes to JS (not) ;-(

https://hg.mozilla.org/mozilla-central/rev/3a804c720f13 https://hg.mozilla.org/mozilla-central/rev/0ab0630eec0c

(For further reference) It is also possible to enforce strict-mode on the JSContext. We currently didn't do that. One way non-strict may sneak in is horrible stuff through Function(). The shared JSM global work still work in presence of non-strict code, but we should really avoid it to avoid potential problems.