Merge pull request #14872 from OmarTawfik/fix-13681-vbc-output-extension

Handle different extensions specified as output name to vbc

docs/compilers/Visual Basic/Compiler Breaking Changes.md

+**This document lists known breaking changes in Roslyn (VS2015+) from the native VB compiler (VS2013 and previous).**
+
+*Breaks are formatted with a monotonically increasing numbered list to allow them to referenced via shorthand (i.e., "known break #1").
+Each entry should include a short description of the break, followed by either a link to the issue describing the full details of the break or the full details of the break inline.*
+
+1. When specifying the output extension as one of the known output types (example /out:foo.dll), but specifying a different target type
+   (example /t:exe) the compiler will now keep the specified extension and won't add the target extension (example foo.dll.exe). See
+   [#13681](https://github.com/dotnet/roslyn/issues/13681) for examples and details.

src/Compilers/VisualBasic/Portable/CommandLine/VisualBasicCommandLineParser.vb

@@ -2216,10 +2216,12 @@ lVbRuntimePlus:
                         outputFileName = outputFileName & ".netmodule"
                     End If
                 Else
-                    Dim defaultExtension As String = kind.GetDefaultExtension()
-                    If Not String.Equals(ext, defaultExtension, StringComparison.OrdinalIgnoreCase) Then
+                    If Not ext.Equals(".exe", StringComparison.OrdinalIgnoreCase) And
+                        Not ext.Equals(".dll", StringComparison.OrdinalIgnoreCase) And
+                        Not ext.Equals(".netmodule", StringComparison.OrdinalIgnoreCase) And
+                        Not ext.Equals(".winmdobj", StringComparison.OrdinalIgnoreCase) Then
                         simpleName = outputFileName
-                        outputFileName = outputFileName & defaultExtension
+                        outputFileName = outputFileName & kind.GetDefaultExtension()
                     End If
 
                     If simpleName Is Nothing Then

src/Compilers/VisualBasic/Test/CommandLine/CommandLineTests.vb

@@ -7944,6 +7944,53 @@ End Class
             Next
         End Sub
 
+        <WorkItem(13681, "https://github.com/dotnet/roslyn/issues/13681")>
+        <Theory()>
+        <InlineData("/t:exe", "/out:foo.dll", "foo.dll", "foo.dll.exe")>                                'Output with known but different extension
+        <InlineData("/t:exe", "/out:foo.dLL", "foo.dLL", "foo.dLL.exe")>                                'Output with known but different extension (different casing)
+        <InlineData("/t:library", "/out:foo.exe", "foo.exe", "foo.exe.dll")>                            'Output with known but different extension
+        <InlineData("/t:library", "/out:foo.eXe", "foo.eXe", "foo.eXe.dll")>                            'Output with known but different extension (different casing)
+        <InlineData("/t:module", "/out:foo.dll", "foo.dll", "foo.dll.netmodule")>                       'Output with known but different extension
+        <InlineData("/t:winmdobj", "/out:foo.netmodule", "foo.netmodule", "foo.netmodule.winmdobj")>    'Output with known but different extension
+        <InlineData("/t:exe", "/out:foo.netmodule", "foo.netmodule", "foo.netmodule.exe")>              'Output with known but different extension
+        <InlineData("/t:library", "/out:foo.txt", "foo.txt.dll", "foo.dll")>                            'Output with unknown extension (.txt)
+        <InlineData("/t:exe", "/out:foo.md", "foo.md.exe", "foo.exe")>                                  'Output with unknown extension (.md)
+        <InlineData("/t:exe", "/out:foo", "foo.exe", "foo")>                                            'Output without extension
+        <InlineData("/t:library", "/out:foo", "foo.dll", "foo")>                                        'Output without extension
+        <InlineData("/t:module", "/out:foo", "foo.netmodule", "foo")>                                   'Output without extension
+        <InlineData("/t:winmdobj", "/out:foo", "foo.winmdobj", "foo")>                                  'Output without extension
+        <InlineData("/t:exe", "/out:foo.exe", "foo.exe", "foo.exe.exe")>                                'Output with correct extension (.exe)
+        <InlineData("/t:library", "/out:foo.dll", "foo.dll", "foo.dll.dll")>                            'Output with correct extension (.dll)
+        <InlineData("/t:module", "/out:foo.netmodule", "foo.netmodule", "foo.netmodule.netmodule")>     'Output with correct extension (.netmodule)
+        <InlineData("/t:module", "/out:foo.NetModule", "foo.NetModule", "foo.NetModule.netmodule")>     'Output with correct extension (.netmodule) (different casing)
+        <InlineData("/t:winmdobj", "/out:foo.winmdobj", "foo.winmdobj", "foo.winmdobj.winmdobj")>       'Output with correct extension (.winmdobj)
+        Public Sub OutputingFilesWithDifferentExtensions(targetArg As String, outArg As String, expectedFile As String, unexpectedFile As String)
+            Dim source =
+                <compilation>
+                    <file name="a.vb">
+                        <![CDATA[
+Module Program
+    Sub Main(args As String())
+    End Sub
+End Module
+]]>
+                    </file>
+                </compilation>
+
+            Dim fileName = "a.vb"
+            Dim dir = Temp.CreateDirectory()
+            Dim sourceFile = dir.CreateFile(fileName)
+            sourceFile.WriteAllText(source.Value)
+
+            Dim output As New StringWriter()
+
+            Assert.Equal(0, New MockVisualBasicCompiler(Nothing, dir.Path, {fileName, targetArg, outArg}).Run(output, Nothing))
+            Assert.True(File.Exists(Path.Combine(dir.Path, expectedFile)), "Expected to find: " & expectedFile)
+            Assert.False(File.Exists(Path.Combine(dir.Path, unexpectedFile)), "Didn't expect to find: " & unexpectedFile)
+
+            CleanupAllGeneratedFiles(sourceFile.Path)
+        End Sub
+
     End Class
 
     <DiagnosticAnalyzer(LanguageNames.VisualBasic)>