Bug 5638 - UITableViewSource::SectionIndexTitles trampoline call results in _sigtramp signalled.
Summary: UITableViewSource::SectionIndexTitles trampoline call results in _sigtramp si...
Alias: None
Product: iOS
Classification: Xamarin
Component: XI runtime ()
Version: 5.3.x
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Rolf Bjarne Kvinge [MSFT]
Depends on:
Reported: 2012-06-13 14:44 UTC by Matthew Tebbs
Modified: 2012-07-26 12:19 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

Stack trace with native_to_managed_trampoline_MuddyTummy_UI_iOS_TableView_GroupedListSource_1_SectionIndexTitles. (7.76 KB, text/plain)
2012-06-13 14:44 UTC, Matthew Tebbs
Reduced test case. (8.70 KB, application/zip)
2012-06-20 17:22 UTC, Matthew Tebbs

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Description Matthew Tebbs 2012-06-13 14:44:48 UTC
Created attachment 2049 [details]
Stack trace with native_to_managed_trampoline_MuddyTummy_UI_iOS_TableView_GroupedListSource_1_SectionIndexTitles.

As an aside this issue is showing in a similar section of code to the last one I entered (https://bugzilla.novell.com/show_bug.cgi?id=684281 imported as http://bugzilla.xamarin.com/show_bug.cgi?id=54).

Description of Issue:

When executed on device (debug or release) _sigtramp is signalled in context of UITableViewSource::SectionIndexTitles() call. Attached files shows stack trace.

Disabling the new trampolines by adding --noregistrar to mtouch arguments does not reproduce the issue.

If you note in the stack trace GroupedListSource is the context. The base class of this is a generic,

public abstract class Source<T> : UITableViewSource /* UITableViewDataSource and UITableViewDelegate combined */ where T : class
    ... foo ...

And GroupedListSource is derived from this thus,

public abstract class GroupedListSource<T> : Source<T> where T : class
    public override string[] SectionIndexTitles(UITableView tableview)
        ... foo ...


Mono 2.10.9
MonoTouch 5.3.4
Mac OS X 10.7.4
iOS 5.1.1

I expect that I can provide reduced code that reproduces the issue if required.
Comment 1 Rolf Bjarne Kvinge [MSFT] 2012-06-20 08:32:07 UTC
I tried the sample project here: https://bugzilla.novell.com/show_bug.cgi?id=684281#c7, but it works correctly, so I'd appreciate it if you could upload a new test case.

It doesn't have to be a reduced test case, registrar bugs are usually quite easy to find even with big test cases.
Comment 2 Matthew Tebbs 2012-06-20 17:22:08 UTC
Created attachment 2094 [details]
Reduced test case.

Oddly there are two variants, at bottom of tableview main file, such that one will reproduce the __sigtramp and the other will not. The difference is an enum value passed as an argument.
Comment 3 Rolf Bjarne Kvinge [MSFT] 2012-06-21 06:17:53 UTC
Fixed (monotouch master: 2072b1a518044a346f5d9cb0f7ae09cb0b9dda7a).

The fix will be included in 5.3.5.

The crash happens when SectionIndexTitles returns null, so for a workaround you can just return an zero-length array instead in SectionIndexTitles until the next version is released.
Comment 4 Matthew Tebbs 2012-06-21 12:37:47 UTC
Verified the workaround fixed the issue with 5.3.4. I'll wait on 5.3.5 to revert the change and re-verify. Thanks Rolf.
Comment 5 Matthew Tebbs 2012-07-26 12:19:41 UTC
Verified fix in 5.3.5 Beta with my local code sans workaround. Thanks.