Bug 60065 - Make exception marshaling work with system mono
Summary: Make exception marshaling work with system mono
Status: Tracked in Related Links
Alias: None
Product: Xamarin.Mac
Classification: Desktop
Component: Runtime ()
Version: Master
Hardware: PC Mac OS
: --- normal
Target Milestone: 15.8
Assignee: Rolf Bjarne Kvinge [MSFT]
URL:
Depends on:
Blocks:
 
Reported: 2017-10-09 17:11 UTC by Rolf Bjarne Kvinge [MSFT]
Modified: 2018-07-03 00:59 UTC (History)
3 users (show)

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

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Related Links:
Status:
Tracked in Related Links

Description Rolf Bjarne Kvinge [MSFT] 2017-10-09 17:11:47 UTC
[Spinoff from bug #59979, which ended up a confusing mess due to fixes from several teams included - this bug is about the problem in Xamarin.Mac]

Slack:

> Alan McGovern [12:53] 2017-10-05 11:52:49.733 MonoDevelop[46104:4956973] Xamarin.Mac: Could not load mono_set_pending_exception
> Alan McGovern [12:54] any idea why that's crashing my IDE?
> Alan McGovern [12:54] https://gist.github.com/alanmcgovern/b39f921c6cf14ab6f2e78abac2f74c94
> 
> Rolf Kvinge [12:56] let me look
> 
> Rolf Kvinge [12:57] https://github.com/xamarin/ios-sim-sharp/blob/7b7a174d398a3ccd2b82936619b3f74d8baa7e73/MonoTouch.Hosting/Bindings/Library64.cs#L39
> Rolf Kvinge [12:57] it's the `[MarshalNativeExceptions]` attribute
> 
> Alan McGovern [12:58] yeah - we want to marshal native exceptions
> 
> Rolf Kvinge [12:58] XM will catch the native exception, convert it to a managed exception, and call `mono_set_pending_exception`
> 
> Alan McGovern [12:58] as we have for 5-6 years now :stuck_out_tongue:
> 
> Rolf Kvinge [12:58] but `mono_set_pending_exception` is a private symbol, so XM doesn't find it
> Rolf Kvinge [12:58] and then aborts
> 
> Alan McGovern [12:58] why is it private?
> Alan McGovern [12:58] that's an ABI breakage by the sounds of it
> 
> Rolf Kvinge [12:59] it's not public in the headers
> 
> Alan McGovern [12:59] when did it become not-public?
> 
> Rolf Kvinge [12:59] which works as long as you link statically
> Rolf Kvinge [12:59] but it breaks when using the system libmono.dylib
> 
> Alan McGovern [12:59] this is the configuration we've been shipping for years now
> 
> Rolf Kvinge [13:00] it probably broke when I implemented better support for marshalling exceptions


PR in progress which needs to be completed: https://github.com/mono/mono/pull/4654

Workaround to call mono_raise_exception if mono_set_pending_exception isn't available:

master: https://github.com/xamarin/xamarin-macios/pull/2845 
d15-5: https://github.com/xamarin/xamarin-macios/pull/2853
Comment 1 Rolf Bjarne Kvinge [MSFT] 2018-03-22 12:38:19 UTC
New mono PR: https://github.com/mono/mono/pull/7759