CompileAssemblyFromSource leaks handles

microsoft.public.dotnet.framework

20 Oct 2007 9:52 PM

AMercer

Microsoft.VisualBasic.VBCodeProvider.CompileAssemblyFromSource() leaks a
handle at every call. Under the IDE (VS2005), it leaks two handles at every
call. This behavior does not vary with different params (see sample below).

When GenerateInMemory is true and the compilation is successful, there is
also a memory 'leak' owing to the new assembly being added to the current
AppDomain and hence memory growth. This 'leak' has received comment in the
past, and it is not the topic of this inquiry. The handle leak I am talking
about is the process's handle count as reported by the task manager.

I have searched high and low for things to dispose/close/whatever. I have
found nothing beyond the dispose in the sample below. Am I missing
something? Or is this a CodeDom bug?

------------------------

Public Shared Function Problem() As String ' codedom leak problem
    ' CompileAssemblyFromSource() always leaks two handles as indicated by
task manager
    ' It also leaks about 1k memory if the compile was successful and
GenerateInMemory is true - an expected result

    ' make SourceCode, the code to compile
    Dim aSourceCode() As String = { _
      " Public Class DynamicClass
       ", _
      "    Public Shared Function DynamicFunction( Byval d as double ) as
boolean   ", _
      "      Return d>0.5
       ", _
      "    End Function
       ", _
      " End Class
       "}
    Dim SourceCode As String = Join(aSourceCode, vbLf)

    ' make params, the compiler parameters
    Dim params As New CodeDom.Compiler.CompilerParameters
    'params.GenerateInMemory = True ' Assembly is created in memory
    params.OutputAssembly = "DynamicDll" ' or assembly created on a dll
    'params.TreatWarningsAsErrors = True
    'params.WarningLevel = 4
    'params.CompilerOptions = "/optionexplicit+ /optionstrict+
/optioncompare:text /optimize- /debug+ /warnaserror+ /nowarn:42024"
    'Dim refs() As String = {"System.dll", "Microsoft.VisualBasic.dll"}
    'params.ReferencedAssemblies.AddRange(refs)

    ' make results by compiling the source code
    Dim provider As New Microsoft.VisualBasic.VBCodeProvider
    Dim results As CodeDom.Compiler.CompilerResults
    results = provider.CompileAssemblyFromSource(params, SourceCode) ' cause
of the leak
    provider.Dispose()

    ' make and return errors
    ' none of this is necessary for exhibiting the leaks
    Dim errors As String = ""
    If results Is Nothing Then
      errors = "results is nothing"
    Else
      For Each out As String In results.Output
        errors &= out & vbLf
      Next out
    End If
    Return errors

End Function