Handle PDB location when project build externally (#1354)

Handle PDB location when project build externally

src/coverlet.core/Abstractions/ISourceRootTranslator.cs

@@ -8,6 +8,7 @@ namespace Coverlet.Core.Abstractions
 {
     internal interface ISourceRootTranslator
     {
+        bool AddMappingInCache(string originalFileName, string targetFileName);
         string ResolveFilePath(string originalFileName);
         string ResolveDeterministicPath(string originalFileName);
         IReadOnlyList<SourceRootMapping> ResolvePathRoot(string pathRoot);

src/coverlet.core/Helpers/InstrumentationHelper.cs

@@ -90,14 +90,32 @@ namespace Coverlet.Core.Helpers
                 if (entry.Type == DebugDirectoryEntryType.CodeView)
                 {
                     CodeViewDebugDirectoryData codeViewData = peReader.ReadCodeViewDebugDirectoryData(entry);
-                    if (_sourceRootTranslator.ResolveFilePath(codeViewData.Path) == $"{Path.GetFileNameWithoutExtension(module)}.pdb")
+                    string modulePdbFileName = $"{Path.GetFileNameWithoutExtension(module)}.pdb";
+                    if (_sourceRootTranslator.ResolveFilePath(codeViewData.Path) == modulePdbFileName)
                     {
                         // PDB is embedded
                         embedded = true;
                         return true;
                     }
 
-                    return _fileSystem.Exists(_sourceRootTranslator.ResolveFilePath(codeViewData.Path));
+                    if (_fileSystem.Exists(_sourceRootTranslator.ResolveFilePath(codeViewData.Path)))
+                    {
+                        // local PDB is located within original build location
+                        embedded = false;
+                        return true;
+                    }
+
+                    string localPdbFileName = Path.Combine(Path.GetDirectoryName(module), modulePdbFileName);
+                    if (_fileSystem.Exists(localPdbFileName))
+                    {
+                        // local PDB is located within same folder as module
+                        embedded = false;
+
+                        // mapping need to be registered in _sourceRootTranslator to use that discovery
+                        _sourceRootTranslator.AddMappingInCache(codeViewData.Path, localPdbFileName);
+
+                        return true;
+                    }
                 }
             }
 

src/coverlet.core/Helpers/SourceRootTranslator.cs

@@ -108,6 +108,17 @@ namespace Coverlet.Core.Helpers
             return mapping;
         }
 
+        public bool AddMappingInCache(string originalFileName, string targetFileName)
+        {
+            if (_resolutionCacheFiles != null && _resolutionCacheFiles.ContainsKey(originalFileName))
+            {
+                return false;
+            }
+
+             (_resolutionCacheFiles ??= new Dictionary<string, string>()).Add(originalFileName, targetFileName);
+            return true;
+        }
+
         public IReadOnlyList<SourceRootMapping> ResolvePathRoot(string pathRoot)
         {
             return _sourceRootMapping.TryGetValue(pathRoot, out List<SourceRootMapping> sourceRootMapping) ? sourceRootMapping.AsReadOnly() : null;

test/coverlet.core.tests/Helpers/InstrumentationHelperTests.cs

@@ -54,12 +54,27 @@ namespace Coverlet.Core.Helpers.Tests
         }
 
         [Fact]
-        public void TestHasPdb()
+        public void TestHasPdbOfLocalAssembly()
         {
             Assert.True(_instrumentationHelper.HasPdb(typeof(InstrumentationHelperTests).Assembly.Location, out bool embeddedPdb));
             Assert.False(embeddedPdb);
         }
 
+        [Fact]
+        public void TestHasPdbOfExternalAssembly()
+        {
+            string testAssemblyLocation = GetType().Assembly.Location;
+
+            string externalAssemblyFileName = Path.Combine(
+                Path.GetDirectoryName(testAssemblyLocation),
+                "TestAssets",
+                "75d9f96508d74def860a568f426ea4a4.dll"
+            );
+
+            Assert.True(_instrumentationHelper.HasPdb(externalAssemblyFileName, out bool embeddedPdb));
+            Assert.False(embeddedPdb);
+        }
+
         [Fact]
         public void TestBackupOriginalModule()
         {