In bug 1348087 we started using nsIResumableChannel to resume update downloads, but I didn't handle the case where the server sends Accept-Ranges: none to explicitly disable resuming; in that case, accessing the entityID property of the request will throw NS_ERROR_NOT_RESUMABLE, which we should be catching. The download manager does this at: https://searchfox.org/mozilla-central/rev/30ead7d1ae5bf95b8bc0fd67b950cd46ca05e32c/toolkit/components/jsdownloads/src/DownloadCore.jsm#2013 My plan for this bug is to copy over that logic.

Marking this as a blocker for 58.

From discussion on irc, sounds like this affected b1 users (on the dev edition channel only) so we have a good chance to fix it if we land a patch before Monday morning, when we plan to build 58.0b3 for the beta channel.

Comment on attachment 8927395 [details] Bug 1416295 - Support downloading updates from servers that don't support resuming. https://reviewboard.mozilla.org/r/198696/#review203812 LGTM ::: toolkit/mozapps/update/nsUpdateService.js:3606 (Diff revision 1) > + // Reading the entityID can throw if the server doesn't allow resuming. > + try { > - this._patch.setProperty("entityID", request.entityID); > + this._patch.setProperty("entityID", request.entityID); > + } catch (ex) { > + if (!(ex instanceof Components.Exception) || > + ex.result != Cr.NS_ERROR_NOT_RESUMABLE) { Nit: align with the first paren, not the second, since this is excluded from the second paren's clause.

The Mac jobs on try haven't started yet, but everything else passed, so I'm landing this.

Pushed by mhowell@mozilla.com: https://hg.mozilla.org/integration/autoland/rev/df5703f27971 Support downloading updates from servers that don't support resuming. r=dthayer