1178799 - TEST-UNEXPECTED-FAIL | editor/libeditor/tests/browserscope/test_richtext2.html | application terminated with exit code 11

Status: RESOLVED FIXED

(Core :: Widget: Gtk, defect)

Description

[Andrew Comminos [:acomminos]]

This intermittent crash occurs fairly frequently on the test infrastructure for GTK3 on linux32- it appears to be caused by upstream GTK bug 719314 (https://bugzilla.gnome.org/show_bug.cgi?id=719314).

Some debugging has revealed that this is caused by affected GTK versions making a selection request from a null requestor (window). Perhaps it would make sense to disable this test for GTK3.

Comment 1

[Andrew Comminos [:acomminos]]

Attachment: Fix GDK selection event synthesis on GTK3.

Looks like this one is our fault; our GDK_SELECTION_NOTIFY events generated lack a requestor (new in GTK3). While the upstream fix causes it not to crash, it's a trivial fix on our side.

This patch should properly set the selection requestor and prevent the crash.

Try (GTK3, affected test only): https://treeherder.mozilla.org/#/jobs?repo=try&revision=02207335b4f5

Comment 2

[Andrew Comminos [:acomminos]]

Comment on attachment 8629500 [details] [diff] [review]
Fix GDK selection event synthesis on GTK3.

Appears that the test is still busting. Looking into it.

Comment 3

[Andrew Comminos [:acomminos]]

The crash is caused by another X window calling XConvertSelection (sending a SelectionRequest) while nsClipboard is waiting for the clipboard to be updated with its modified X11 event loop (see RetrievalContext::Wait). If the client requesting input dies before the waiting finishes, the queued up SelectionRequest event will have requestor == NULL- triggering GTK bug 719314 (https://bugzilla.gnome.org/show_bug.cgi?id=719314).

This can be reproduced locally by running editor/libeditor/tests/browserscope/test_richtext2.html at the same time as an `xsel -b` loop.

There are two solutions I can think of:

1) Filter X11 SelectionRequest events with an unreachable window using a GDK event filter.
2) Handle SelectionRequest events in our custom X event loop.

Comment 4

[Andrew Comminos [:acomminos]]

Attachment: Filter X11 SelectionRequest events with an invalid requestor on GTK3.

Here's an example of the filter approach. I think that this is preferable as it can catch SelectionRequest events with null requestors even outside of the custom clipboard event loop. Thanks!

Try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=41caac039337

Comment 5

[Karl Tomlinson (:karlt)]

Comment on attachment 8631634 [details] [diff] [review]
Filter X11 SelectionRequest events with an invalid requestor on GTK3.

>+// A custom event filter to workaround attempting to dereference a null
>+// selection requestor in GTK3 versions before 3.10. See bug 1178799.

https://bugzilla.gnome.org/show_bug.cgi?id=719314 implies the bug existed with
3.10.5.

>+#if (MOZ_WIDGET_GTK == 3) && defined(MOZ_X11)
>+    gdk_window_add_filter(nullptr, selection_request_filter, nullptr);
>+#endif

Please add a runtime check for the appropriate version and only add the filter
when running against the version with the bug.  That protects against any
future protocols that may use a null requestor for some reason, and makes
things a little more efficient than finding the window properties twice.

No need to make the remove conditional.  The remove will be a no-op if it
hasn't been added.

r+ with those addressed, thank you.

Comment 6

[Andrew Comminos [:acomminos]]

Attachment: Filter X11 SelectionRequest events with an invalid requestor on GTK3. Carry r=karlt

Updated, thanks. Appears that the earliest unaffected GTK version was 3.11.3.

Comment 7

[Andrew Comminos [:acomminos]]

Attachment: Filter X11 SelectionRequest events with an invalid requestor on GTK3. Carry r=karlt

Updated to re-add MOZ_X11 and MOZ_WIDGET_GTK == 3 check.

Comment 8

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/1bb9ee25eb2c

Comment 9

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/1bb9ee25eb2c