610624 - error "window is null" in page-mods

Status: RESOLVED DUPLICATE of bug 616785

(Add-on SDK Graveyard :: General, defect)

Description

[Dietrich Ayala (:dietrich)]

made a simple page-mod in main.js global scope. seeing this on every page load in the nightly and beta 6:

error: An exception occurred.
Traceback (most recent call last):
  File "chrome://global/content/bindings/autocomplete.xml", line 1100, in 
    document.getAnonymousElementByAttribute(this, "anonid", "richlistbox");
  File "resource://jid0-bqnxcbiimtovbokmk1n4s8f1eqe-jetpack-core-lib/observer-service.js", line 174, in 
    this.callback(subject, data);
  File "resource://jid0-bqnxcbiimtovbokmk1n4s8f1eqe-addon-kit-lib/page-mod.js", line 180, in _onContentWindow
    if (RULES[rule].test(window.document.URL))
TypeError: window is null

Comment 1

[Dietrich Ayala (:dietrich)]

Seeing this still. I think it blocks, since the page-mod is not executed.

Code:

const pageMods = require("page-mod");
pageMods.PageMod({
  include: "https://builder.mozillalabs.com/addon/*",
  contentScriptURL: require("self").data.url("addon-builder.js"),
  contentScriptWhen: "ready"
});

Error:

error: An exception occurred.
Traceback (most recent call last):
  File "resource://jid0-bqnxcbiimtovbokmk1n4s8f1eqe-jetpack-core-lib/observer-service.js", line 174, in 
    this.callback(subject, data);
  File "resource://jid0-bqnxcbiimtovbokmk1n4s8f1eqe-addon-kit-lib/page-mod.js", line 184, in _onContentWindow
    if (RULES[rule].test(window.document.URL))
TypeError: window is null

Comment 2

[Dietrich Ayala (:dietrich)]

Blocking 0.10 until we figure it out.

Comment 3

[Irakli Gozalishvili [:irakli] [:gozala] [@gozala]]

Attachment: Pointer to pull request

Comment 4

[Irakli Gozalishvili [:irakli] [:gozala] [@gozala]]

It seems that awesomebar's atocomplete dialog triggers document-element-inserted with an argument who's defaultView is null. Pull request contains a workaround to this problem.

Comment 5

[Dietrich Ayala (:dietrich)]

Unblocking 0.10 on this, since the reason my script wasn't executing was because I was using contentScriptURL instead of contentScriptFile :P

However, this patch *does* fix the reported error. I'm not clear on what the root cause is - can you explain how/why autocomplete code would send that event?

Comment 6

[Myk Melez [:myk] [@mykmelez]]

The root cause is that Gecko notifiers observers about document-element-inserted for all documents, including chrome XML documents; but page-mod only supports HTML documents and assumes all inserted documents have windows, thus generating this exception.

Back before document-element-inserted, when page-mod was observing content-document-global-created, this wasn't a problem, presumably because XML documents don't have "content-document-global" objects (i.e. windows).

I just checked in a fix over in bug 616785, not knowing about this bug until I had already filed that one and created a patch.  I decided to check in that patch instead of this one because its comment mentions that these are XML documents.

In any case, this is now resolved.