User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.96 Safari/537.36 Steps to reproduce: 1. Open a new tab. 2. Open developer web console. 3. paste the following script once line after another. var spellCheckerInput = document.documentElement.appendChild(document.createElementNS("http://www.w3.org/1999/xhtml", "input")); var editor = spellCheckerInput.QueryInterface(Ci.nsIDOMNSEditableElement).editor; var spellChecker = Components.classes["@mozilla.org/editor/editorspellchecker;1"].createInstance(Ci.nsIEditorSpellCheck); spellChecker.InitSpellChecker(editor, false); The code seem pretty close to the following test: https://dxr.mozilla.org/mozilla-central/source/editor/composer/test/test_bug1219928.html Actual results: Firefox crashes Expected results: Spellchecker should be initialized.

I have noticed that the IDL of this service has 3rd optional callback parameter. Once i have added it the issues was solved. So, I guess it is not optional anymore. I think it's worth updating the the docs. https://developer.mozilla.org/en-US/docs/Mozilla/Tech/XPCOM/Reference/Interface/nsIEditorSpellCheck#InitSpellChecker()

Regression range: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=c885f6b0de36ab24fa52b4a96d949c04a0dd00d5&tochange=0a82045b156396cad9d76643b7346abb9af79c78 Makoto Kato — Bug 1330912 - Part 1. Add async version of SetCurrentDictionary using list. r=Ehsan CR: https://crash-stats.mozilla.com/report/index/4010a4b3-d250-4604-8041-4d9a00170517

Comment on attachment 8868902 [details] Bug 1365383 - Spellchecker should consider that callback isn't set. https://reviewboard.mozilla.org/r/140530/#review143962 ::: editor/composer/test/test_bug1365383.html:40 (Diff revision 1) > + .onSpellCheck(textarea, () => { > + // Callback parameter isn't set > + spellChecker.UpdateCurrentDictionary(); > + > + var canSpellCheck = spellChecker.canSpellCheck(); > + is(canSpellCheck, true, 'spellCheck is enabled'); Why don't you use ok()?

tracking as new crash in 55.

Pushed by m_kato@ga2.so-net.ne.jp: https://hg.mozilla.org/integration/autoland/rev/f8b25d64b513 Spellchecker should consider that callback isn't set. r=masayuki

assafdd: I have a question. How did you find this bug? I mean, why did you try to create an instance of nsIEditorSpellCheck? I'm working on improving editor's performance, and my patches hit unexpected behavior in an automated test added by this bug's fix. So, if it was just for creating a XUL addon, not allowing to create an instance of nsIEditorSpellCheck from JS, we can get faster editor with simple patch. So, I want to disable it if there is no problem.

Oh, I realized that a lot of addons creates instances f nsIEditorSpellCheck. So, perhaps, we need to keep supporting it. But if you don't mind, let me know why did you found this bug. Thanks.

If I recall correctly, I found it while testing my XUL addon on nightly. AFAIK webexentsions do not have spell check API (which is a little sad), so I do not think this issue is to interesting looking forward.

Thank you. Yes, XUL addons are banned by Firefox and this kind of bugs are not valid on Firefox anymore, but not so by Thunderbird. And I'd like to support Tb's XUL addon's unless it'd cause something too bad for Firefox users because editor and spellchecker are mostly touched by them.