Add BindingFlags.DoNotWrapExceptions

[AustinWise]

The original design review is here: dotnet/corefx#22866 . To summarize, this adds a new flag to BindingFlags called DoNotWrapExceptions. When this flag is used to invoke a method using reflection, any exceptions thrown are not wrapped with a TargetInvocationException.

It has already been implemented in some other version of .NET:

• Implement BindingFlags.DoNotWrapExceptions on Project N dotnet/corert#4437
• Support for not wrapping exceptions with TargetInvocationException. dotnet/coreclr#13767

I would be delighted if this handy feature was also available in Mono.

I have in part based my changes on the CoreCLR implementation. There all already tests for this feature in corefx, so I have added those to the corlib_xtest.dll.sources file.

I have a couple of concerns about my implementation:

• I notice that DynamicMethod.Invoke was ignoring the BindingFlags and other arguments. I changed this method to pass along all the arguments. For what it's worth, it appears that CoreCLR respects these arguments.

[vargaz]

Support for filter clauses is not perfect, it would be better to simply duplicate the body:
if (do-not-wrap) {
call
} else {
try {
call
} catch (...) {
...
}
}

[AustinWise]

I have update my pull request to not use exception filter clauses.

[marek-safar]

approve

[marek-safar]

Please instead of changing this file replace it in corlib.dll.sources with the version from external/corefx/src/Common/src/CoreLib/System/Reflection/BindingFlags.cs

[AustinWise]

Done

[marek-safar]

Should be just private

[AustinWise]

Before this change RuntimeType called Activator.CreateInstance(Type type, bool nonPublic) when a constructor has no arguments. After this change I needed a way to propagate the DoNotWrapExceptions flag, so I added this internal overload.

[marek-safar]

As it's used by CreateInstance only, it does have to be internal

[marek-safar]

approve

[AustinWise]

I noticed that API Diff check failed because of the addition of the new flag. Is that something I should fix in this pull request?

[marek-safar]

We'll take care of apidiff handling

[luhenry]

You should do these 2 modifications to https://github.com/mono/mono/blob/master/mcs/class/corlib/corlib.dll.sources instead. This corlib-net_4_x.csproj is autogenerated from the mcs/class/corlib/*.sources files

[AustinWise]

I have removed my changes from the generated csproj file.

[AustinWise]

@luhenry It appears that a bot periodically regenerates the csproj file so I have removed my changes to that file. Is that what you had in mind?

[marek-safar]

@monojenkins commit apidiff

[luhenry]

@AustinWise yes we do regenerate periodically the csproj files from the *.dll.sources files, so modifying the former will just be overridden by the automatic generation, while modifying the latter will make it happen in the former.