826195 - When leaving print preview: "ASSERTION: print object has mismatching pres shell and pres context: 'false', file /mozilla/layout/printing/nsPrintData.cpp, line 108" followed by "ASSERTION: mPresShell->GetPresShell() is null"

Status: RESOLVED FIXED

(Core :: Print Preview, defect)

Description

[Daniel Holbert [:dholbert]]

STR:
 0. Be using a debug build
 1. Visit about:blank (or perhaps any site...?)
 2. File | Print Preview (on Linux / Windows)
 3. Click "close" button

ACTUAL RESULTS:
###!!! ASSERTION: print object has mismatching pres shell and pres context: 'false', file /mozilla/layout/printing/nsPrintData.cpp, line 108

###!!! ASSERTION: mPresShell->GetPresShell() is null: 'false', file /mozilla/layout/printing/nsPrintData.cpp, line 111

I hit this using a debug build from up-to-date mozilla-central, from this cset:
 https://hg.mozilla.org/mozilla-central/rev/6955309291ee

Comment 1

[Daniel Holbert [:dholbert]]

Actually, looks like these assertions were just added, in bug 818626's cset:
 https://hg.mozilla.org/mozilla-central/rev/28f9ce570aa1

I can reproduce this in the earliest m-c-debug nightly to include that patch...
https://ftp.mozilla.org/pub/mozilla.org/firefox/nightly/2013/01/2013-01-02-mozilla-central-debug/
...so I think this has just been broken since bug 818626 landed.

Comment 2

[Cameron McCormack (:heycam)]

Attachment: patch

Tweak assertion.  Turns out it is valid for the nsPresContext to no longer have a reference to the PresShell, as long as Destroy() has already been called on the PresShell (as far as I can tell).  I'll assert that over in bug 818626.

Comment 3

[Daniel Holbert [:dholbert]]

Comment on attachment 697823 [details] [diff] [review]
patch

Looks like this addresses the first assertion-failure, but not the second one ("mPresShell->GetPresShell() is null")

It sounds like we might just want to drop that second assertion, based on comment 2...?

r=me with that, or something like it.  (The assertion message also needs s/mPresShell/mPresContext/, if we happen to keep it. :))

Comment 4

[Cameron McCormack (:heycam)]

Thanks, removed that other assertion entirely.

https://hg.mozilla.org/integration/mozilla-inbound/rev/9e624b73a293

Comment 5

[Phil Ringnalda (:philor)]

https://hg.mozilla.org/mozilla-central/rev/9e624b73a293