User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0 Build ID: 20171024165158 Steps to reproduce: I'm sorry if this isn't exactly standard practice. I'm a user, not a long-time Firefox maintainer or anything. There seem to be a ton of user reports of spontaneous data loss affecting WebExtensions in Firefox, with no corresponding bugs filed on Bugzilla. Really basic WebExtensions don't need to store any data, but for the most influential Firefox add-ons (think of your Greasemonkeys, your Stylishes, and your NoScripts), data loss is basically a showstopper once it happens to someone. Depending on the add-on, it can literally ruin a user's entire browser experience. If Firefox is replacing its entire add-on system with "Chrome's dinky little add-ons, but also we'll randomly delete all your data," then there's really no reason at all to use Firefox. I thought it might be a good idea to collect what user reports I can find and... well, basically gather them all up in a big pile and throw them at you, to establish that there seems to be *some* sort of intermittent and severe bug. Maybe then, those of you who are more familiar with working on the browser can figure out some sort of strategy to actually investigate this. Actual results: These are Firefox add-on reviews (on AMO) mentioning spontaneous data loss in WebExtensions add-ons. Where possible I've tried to ignore reports that describe an inability to save settings at all, as that may be a separate bug (e.g. WE storage is nuked if cookies are turned off -- Bug 1313401 and Bug 1406675). AMO doesn't give me the option to link to specific reviews, and it doesn't even give me exact dates on reviews, so you'll need to dig a bit for these. Hopefully, review page URLs, usernames, and general timeframes will be enough. Only a couple or so of these add-ons have more than five pages of reviews. == Download all Images == https://addons.mozilla.org/en-GB/firefox/addon/save-all-images-webextension/reviews/ * Review by Yin Cognito three months ago == Instant Translate == https://addons.mozilla.org/en-US/firefox/addon/instant-translate/reviews/ * Review by Anonymous user 2aa827 on October 31 (in Greek) * Review by Mateus in October An additional review (in German) by muximan, seven months ago, describes data loss but specifically ties it to add-on updates. This may be an issue with the add-on itself, or it may be a particularly severe and frequent manifestation of the broader storage bug. == Stylish == https://addons.mozilla.org/en-US/firefox/addon/stylish/reviews/ Stylish's v3.0 update destroys all installed styles, because WebExtensions doesn't seem to offer a viable way to preserve data stored through other means. I am ignoring any reviews that refer only to initial data loss, and focusing on reviews that report recurring or post-update data loss. * Review by renderizer on November 8 == Stylus == https://addons.mozilla.org/en-US/firefox/addon/styl-us/reviews/ * Review by Astoya on October 14 == Tree Tabs == https://addons.mozilla.org/en-US/firefox/addon/tree-tabs/reviews/ * Review by CanIregisterThisTime in October. Response by the add-on developer speculates that the issue is random corruption of localStorage. == uMatrix == https://addons.mozilla.org/en-US/firefox/addon/umatrix/reviews/ uMatrix is apparently a combination of uBlock Origin, NoScript, and RequestPolicy. I'd expect the loss of a user's whitelists to be devastating: just about everything would become unusable. * Review by JazzAnt in October. * Review by Utini in October. * Review by Khys in October. * Review by mthuzla in October. Expected results: Firefox should not delete all of the things, unless the user asks and has made it very very clear that they are very very sure

Maybe depends on bug 1406181.