Skip fsharp construct with unknown source

Documentation/Changelog.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed  
 
+-Fix F# projects with `unkown` source [#1145](https://github.com/coverlet-coverage/coverlet/issues/1145)
 -Fix partially covered throw statement [#1144](https://github.com/coverlet-coverage/coverlet/pull/1144)
 -Fix coverage threshold not failing when no coverage [#1115](https://github.com/coverlet-coverage/coverlet/pull/1115)  
 -Fix partially covered `await foreach` statement [#1107](https://github.com/coverlet-coverage/coverlet/pull/1107) by https://github.com/alexthornton1  

coverlet.sln

@@ -53,6 +53,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Build", "Build", "{9A8B19D4
 		test\Directory.Build.targets = test\Directory.Build.targets
 	EndProjectSection
 EndProject
+Project("{F2A71F9B-5D33-465A-A702-920D77279786}") = "coverlet.tests.projectsample.fsharp", "test\coverlet.tests.projectsample.fsharp\coverlet.tests.projectsample.fsharp.fsproj", "{1CBF6966-2A67-4D2C-8598-D174B83072F4}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -115,6 +117,10 @@ Global
 		{F8199E19-FA9A-4559-9101-CAD7028121B4}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{F8199E19-FA9A-4559-9101-CAD7028121B4}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{F8199E19-FA9A-4559-9101-CAD7028121B4}.Release|Any CPU.Build.0 = Release|Any CPU
+		{1CBF6966-2A67-4D2C-8598-D174B83072F4}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{1CBF6966-2A67-4D2C-8598-D174B83072F4}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{1CBF6966-2A67-4D2C-8598-D174B83072F4}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{1CBF6966-2A67-4D2C-8598-D174B83072F4}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -135,6 +141,7 @@ Global
 		{5FF404AD-7C0B-465A-A1E9-558CDC642B0C} = {2FEBDE1B-83E3-445B-B9F8-5644B0E0E134}
 		{F8199E19-FA9A-4559-9101-CAD7028121B4} = {2FEBDE1B-83E3-445B-B9F8-5644B0E0E134}
 		{9A8B19D4-4A24-4217-AEFE-159B68F029A1} = {2FEBDE1B-83E3-445B-B9F8-5644B0E0E134}
+		{1CBF6966-2A67-4D2C-8598-D174B83072F4} = {2FEBDE1B-83E3-445B-B9F8-5644B0E0E134}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {9CA57C02-97B0-4C38-A027-EA61E8741F10}

src/coverlet.core/Helpers/InstrumentationHelper.cs

@@ -121,12 +121,13 @@ public bool EmbeddedPortablePdbHasLocalSource(string module, out string firstNot
                             {
                                 Document document = metadataReader.GetDocument(docHandle);
                                 string docName = _sourceRootTranslator.ResolveFilePath(metadataReader.GetString(document.Name));
-
+                                Guid languageGuid = metadataReader.GetGuid(document.Language);
                                 // We verify all docs and return false if not all are present in local
                                 // We could have false negative if doc is not a source
                                 // Btw check for all possible extension could be weak approach
-                                // We exlude from the check the autogenerated source file(i.e. source generators)
-                                if (!_fileSystem.Exists(docName) && !docName.EndsWith(".g.cs"))
+                                // We exclude from the check the autogenerated source file(i.e. source generators)
+                                // We exclude special F# construct https://github.com/coverlet-coverage/coverlet/issues/1145
+                                if (!_fileSystem.Exists(docName) && !docName.EndsWith(".g.cs") && !IsUnknownModuleInFSharpAssembly(languageGuid, docName))
                                 {
                                     firstNotFoundDocument = docName;
                                     return false;
@@ -165,16 +166,18 @@ public bool PortablePdbHasLocalSource(string module, out string firstNotFoundDoc
                             _logger.LogWarning($"{nameof(BadImageFormatException)} during MetadataReaderProvider.FromPortablePdbStream in InstrumentationHelper.PortablePdbHasLocalSource, unable to check if module has got local source.");
                             return true;
                         }
+
                         foreach (DocumentHandle docHandle in metadataReader.Documents)
                         {
                             Document document = metadataReader.GetDocument(docHandle);
                             string docName = _sourceRootTranslator.ResolveFilePath(metadataReader.GetString(document.Name));
-
+                            Guid languageGuid = metadataReader.GetGuid(document.Language);
                             // We verify all docs and return false if not all are present in local
                             // We could have false negative if doc is not a source
                             // Btw check for all possible extension could be weak approach
                             // We exlude from the check the autogenerated source file(i.e. source generators)
-                            if (!_fileSystem.Exists(docName) && !docName.EndsWith(".g.cs"))
+                            // We exclude special F# construct https://github.com/coverlet-coverage/coverlet/issues/1145
+                            if (!_fileSystem.Exists(docName) && !docName.EndsWith(".g.cs") && !IsUnknownModuleInFSharpAssembly(languageGuid, docName))
                             {
                                 firstNotFoundDocument = docName;
                                 return false;
@@ -443,5 +446,12 @@ private bool IsAssembly(string filePath)
                 return false;
             }
         }
+
+        private bool IsUnknownModuleInFSharpAssembly(Guid languageGuid, string docName)
+        {
+            // https://github.com/dotnet/runtime/blob/main/docs/design/specs/PortablePdb-Metadata.md#document-table-0x30
+            return languageGuid.Equals(new Guid("ab4f38c9-b6e6-43ba-be3b-58080b2ccce3")) 
+                   && docName.EndsWith("unknown");
+        }
     }
 }

test/coverlet.core.tests/Instrumentation/InstrumenterTests.cs

@@ -513,6 +513,24 @@ public void TestInstrument_MissingModule()
             loggerMock.Verify(l => l.LogWarning(It.IsAny<string>()));
         }
 
+        [Fact]
+        public void CanInstrumentFSharpAssemblyWithAnonymousRecord()
+        {
+            var loggerMock = new Mock<ILogger>();
+
+            string sample = Directory.GetFiles(Directory.GetCurrentDirectory(), "coverlet.tests.projectsample.fsharp.dll").First();
+            InstrumentationHelper instrumentationHelper =
+                new InstrumentationHelper(new ProcessExitHandler(), new RetryHelper(), new FileSystem(), new Mock<ILogger>().Object,
+                    new SourceRootTranslator(sample, new Mock<ILogger>().Object, new FileSystem()));
+
+            var instrumenter = new Instrumenter(sample, "_coverlet_tests_projectsample_fsharp", new CoverageParameters(), loggerMock.Object, instrumentationHelper,
+                new FileSystem(), new SourceRootTranslator(sample, loggerMock.Object, new FileSystem()), new CecilSymbolHelper());
+
+            Assert.True(instrumentationHelper.HasPdb(sample, out bool embedded));
+            Assert.False(embedded);
+            Assert.True(instrumenter.CanInstrument());
+        }
+
         [Theory]
         [InlineData("NotAMatch", new string[] { }, false)]
         [InlineData("ExcludeFromCoverageAttribute", new string[] { }, true)]

test/coverlet.core.tests/coverlet.core.tests.csproj

@@ -24,6 +24,7 @@
     <ProjectReference Include="$(RepoRoot)src\coverlet.msbuild.tasks\coverlet.msbuild.tasks.csproj" />
     <ProjectReference Include="$(RepoRoot)test\coverlet.tests.projectsample.empty\coverlet.tests.projectsample.empty.csproj" />
     <ProjectReference Include="$(RepoRoot)test\coverlet.tests.projectsample.excludedbyattribute\coverlet.tests.projectsample.excludedbyattribute.csproj" />
+    <ProjectReference Include="$(RepoRoot)test\coverlet.tests.projectsample.fsharp\coverlet.tests.projectsample.fsharp.fsproj" />    
     <ProjectReference Include="$(RepoRoot)test\coverlet.core.tests.samples.netstandard\coverlet.core.tests.samples.netstandard.csproj" />
     <ProjectReference Include="$(RepoRoot)test\coverlet.tests.xunit.extensions\coverlet.tests.xunit.extensions.csproj" />
   </ItemGroup>

test/coverlet.tests.projectsample.fsharp/Library.fs

@@ -0,0 +1,4 @@
+namespace coverlet.tests.projectsample.fsharp
+
+module TestModule =
+    type Type1 = Option1 | Option2 of {| x: string |}

test/coverlet.tests.projectsample.fsharp/coverlet.tests.projectsample.fsharp.fsproj

@@ -0,0 +1,12 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net5.0</TargetFramework>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Include="Library.fs" />
+  </ItemGroup>
+
+</Project>