[Mono-devel-list] [PATCH] Fix for runtime version selection and improved assembly remapping

[Lluis Sanchez]

Hi!

This patch fixes two issues. First of all, it fixes the bug #62913,
which is about selecting the correct runtime for an executable.
Right now, an executable compiled with .NET 2.0 or gmcs will try to run
using the mono 2.0 framework, even if this framework is not installed,
in which case it will crash. With the patch, mono checks that the
mscorlib for the requested framework version exists. If it does not, it
will fall-back to the next supported framework. This means that an
application with the following .config file:

<configuration>
	<startup>
		<supportedRuntime version="v2.0.40607"/>
		<supportedRuntime version="v1.1.4322"/>
	</startup>
</configuration>

will properly fall-back to v1.1.4322 if v2.0.40607 is not installed.

The other issue that the patch fixes is related again to assembly
version remapping. It turns out that some assemblies which do not use
the same version numbers as mscorlib also need to be in sync with the
runtime. Those assemblies are Microsoft.VisualBasic and
Microsoft.VisualC. This is specially a problem for
Microsoft.VisualBasic, since all assemblies compiled with VB will
reference it.

With the patch, we have several system assembly version sets for each
runtime version, not just one. Then, each system assembly is linked to a
specific version set, which is used for remapping.

Another change I've made is to allow version remapping even if the
assembly being loaded is newer than the selected system assembly. Paolo
suggested not to remap in this case, but not doing it has some issues.
For example, an application compiled with gmcs will contain references
to 2.0 assemblies, and it will fail when trying to run in a system that
does not have the 2.0 assemblies installed. If we remap to 1.1, it has
at least a chance to run.

Comments are welcome!
Lluis.