K Web crashes when changing to net45 CLR after having changed to CoreCLR

[ctorre]

Reproduced by just testing the HelloWeb Sample:

1. Run "k web" the first time over net45 CLR --> Works over net45
2. Change to Core-CLR with "set TARGET_FRAMEWORK=k10"
3. Run "k web" over CORE-CLR --> Works on Core-CLR
4. Change to net45-CLR with "set TARGET_FRAMEWORK=net45"
5. Run "k web" on CORE-CLR --> Crashes (see error below):

On the other hand, if I set TARGET_FRAMEWORK to empty ("set TARGET_FRAMEWORK="), then, it works on net45 CLR, like "by default CLR".
I think it should work with the environment variable set to "net45", too.

C:\Users\cesardl\Documents\GitHub\Preview\samples\HelloWeb>k web
Loaded Module: klr.net45.dll
Found DLL Export: CallApplicationMain

Unhandled Exception: System.AggregateException: One or more errors occurred. ---
> System.ArgumentException: Illegal characters in path.
   at System.IO.Path.CheckInvalidPathChars(String path, Boolean checkAdditional)

   at System.IO.Path.NormalizePath(String path, Boolean fullCheck, Int32 maxPath
Length, Boolean expandShortPaths)
   at System.IO.Path.GetFullPathInternal(String path)
   at System.IO.Path.GetFullPath(String path)
   at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()
   at System.Linq.Enumerable.<SelectManyIterator>d__14`2.MoveNext()
   at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
   at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
   at klr.hosting.RuntimeBootstrapper.<Execute>d__1.MoveNext()
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceled
Exceptions)
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotifica
tion)
   at System.Threading.Tasks.Task`1.get_Result()
   at DomainManager.Main(Int32 argc, String[] argv)

[rjdudley]

I can replicate this issue also. Once this happens, it prevents any application from running again. I have to close the command window to clear the error.

[Praburaj]

To run it on net45 just clear the value of the env variable SET TARGET_FRAMEWORK= rather than setting it to net45.

[glennc]

Switching between Core CLR and Desktop has now changed completely. This error should not happen anymore.