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Created attachment 24198 [details]
test case (for desktop)
System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture (ex).Throw () doesn't work correctly when called in a reverse pinvoke.
The bug goes like this:
* System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture (ex) will capture the exception information
* .Throw () will throw the exception
* The reverse-invoke will capture the exception, and throw (not rethrow) it.
* Throwing the exception (instead of re throwing it) will clear the stack trace.
* Mono will then try to setup the stack again, and set MonoException.trace_ips to NULL (because there are no managed frames on the stack): https://github.com/mono/mono/blob/9ba3fa0ba37c3b11b7129c3092a379711fd128e4/mono/mini/mini-exceptions.c#L1519
* The native MonoException.trace_ips field maps to the managed System.Exception._stackTrace
* System.Exception.GetStackTrace has different behavior whether the _stackTrace field is null or not: https://github.com/mono/mono/blob/9ba3fa0ba37c3b11b7129c3092a379711fd128e4/mcs/class/referencesource/mscorlib/system/exception.cs#L382. If the _stackTrace field is null, then a remoting stack trace is returned, and since that's also obviously null (no remoting in the attached test case), Exception.GetStackTrace returns null.
* As a result, the StackTrace for the thrown exception is null, even if System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture was used to (attempt to) capture it.
* Set MonoException.trace_ips to an empty array instead of NULL if there are no managed frames: https://gist.github.com/rolfbjarne/915177f818e57c02fb2b40dc691740dc
This is a spin-off of bug #58352.
This is a mono regression, for the attached test case:
> Mono JIT compiler version 126.96.36.199 (2017-02/9667aa6 Fri May 5 09:12:57 EDT 2017)
> Mono JIT compiler version 188.8.131.52 (2017-04/161f032 Wed Jul 26 15:23:07 EDT 2017)
> Mono JIT compiler version 5.7.0 (master/b89b696e71f Tue Aug 15 19:38:06 CEST 2017)
However it seems like it's been failing a while for XI, I tested this as far back as XI 10.0 ("mtouch 10.0.1.10 (cycle8-sr0-xi: ad1cd42)") using the test case from bug #58352, and it failed in all versions.
Moving to 15.5 as this will not make 15.4
Got fixed by the fix for: