Removes the not instrumented/unused instrumenter results so coverage file doesn't get polluted with unused modules

README.md

@@ -68,6 +68,7 @@ Options:
   --include          Filter expressions to include specific modules and types.
   --exclude-by-file  Glob patterns specifying source files to exclude.
   --merge-with       Path to existing coverage result to merge.
+  --exclude-non-called-files	Exclude non called/non instrumented files from coverage.
 ```
 
 #### Code Coverage

src/coverlet.console/Program.cs

@@ -35,6 +35,7 @@ static int Main(string[] args)
             CommandOption includeFilters = app.Option("--include", "Filter expressions to include only specific modules and types.", CommandOptionType.MultipleValue);
             CommandOption excludedSourceFiles = app.Option("--exclude-by-file", "Glob patterns specifying source files to exclude.", CommandOptionType.MultipleValue);
             CommandOption mergeWith = app.Option("--merge-with", "Path to existing coverage result to merge.", CommandOptionType.SingleValue);
+            CommandOption excludeNonCalledFiles = app.Option("--exclude-non-called-files", "Exclude non called/non instrumented files from coverage report", CommandOptionType.NoValue);
 
             app.OnExecute(() =>
             {
@@ -44,7 +45,7 @@ static int Main(string[] args)
                 if (!target.HasValue())
                     throw new CommandParsingException(app, "Target must be specified.");
 
-                Coverage coverage = new Coverage(module.Value, excludeFilters.Values.ToArray(), includeFilters.Values.ToArray(), excludedSourceFiles.Values.ToArray(), mergeWith.Value());
+                Coverage coverage = new Coverage(module.Value, excludeFilters.Values.ToArray(), includeFilters.Values.ToArray(), excludedSourceFiles.Values.ToArray(), mergeWith.Value(), excludeNonCalledFiles.HasValue());
                 coverage.PrepareModules();
 
                 Process process = new Process();

src/coverlet.core/Coverage.cs

@@ -19,20 +19,22 @@ public class Coverage
         private string[] _includeFilters;
         private string[] _excludedSourceFiles;
         private string _mergeWith;
+        private bool _excludeNonCalledFiles;
         private List<InstrumenterResult> _results;
 
         public string Identifier
         {
             get { return _identifier; }
         }
 
-        public Coverage(string module, string[] excludeFilters, string[] includeFilters, string[] excludedSourceFiles, string mergeWith)
+        public Coverage(string module, string[] excludeFilters, string[] includeFilters, string[] excludedSourceFiles, string mergeWith, bool excludeNonCalledFiles)
         {
             _module = module;
             _excludeFilters = excludeFilters;
             _includeFilters = includeFilters;
             _excludedSourceFiles = excludedSourceFiles;
             _mergeWith = mergeWith;
+            _excludeNonCalledFiles = excludeNonCalledFiles;
 
             _identifier = Guid.NewGuid().ToString();
             _results = new List<InstrumenterResult>();
@@ -63,7 +65,7 @@ public void PrepareModules()
 
         public CoverageResult GetCoverageResult()
         {
-            CalculateCoverage();
+            CalculateCoverage(_excludeNonCalledFiles);
 
             Modules modules = new Modules();
             foreach (var result in _results)
@@ -160,13 +162,20 @@ public CoverageResult GetCoverageResult()
             return coverageResult;
         }
 
-        private void CalculateCoverage()
+        private void CalculateCoverage(bool excludeNonCalledFiles)
         {
+            var resultsToRemove = new List<InstrumenterResult>();
             foreach (var result in _results)
             {
                 if (!File.Exists(result.HitsFilePath))
                 {
-                    // File not instrumented, or nothing in it called.  Warn about this?
+                    // File not instrumented, or nothing in it called.
+                    // Mark to be removed so no non used modules are included in coverage file?
+                    if (excludeNonCalledFiles)
+                    {
+                        resultsToRemove.Add(result);
+                    }
+
                     continue;
                 }
 
@@ -205,33 +214,38 @@ private void CalculateCoverage()
                     }
                 }
 
-                // for MoveNext() compiler autogenerated method we need to patch false positive (IAsyncStateMachine for instance) 
-                // we'll remove all MoveNext() not covered branch              
-                foreach (var document in result.Documents)
-                {
-                    List<KeyValuePair<(int, int), Branch>> branchesToRemove = new List<KeyValuePair<(int, int), Branch>>();
-                    foreach (var branch in document.Value.Branches)
-                    {
-                        //if one branch is covered we search the other one only if it's not covered
-                        if (CecilSymbolHelper.IsMoveNext(branch.Value.Method) && branch.Value.Hits > 0)
-                        {
-                            foreach (var moveNextBranch in document.Value.Branches)
-                            {
-                                if (moveNextBranch.Value.Method == branch.Value.Method && moveNextBranch.Value != branch.Value && moveNextBranch.Value.Hits == 0)
-                                {
-                                    branchesToRemove.Add(moveNextBranch);
-                                }
-                            }
-                        }
-                    }
-                    foreach (var branchToRemove in branchesToRemove)
-                    {
-                        document.Value.Branches.Remove(branchToRemove.Key);
-                    }
+                // for MoveNext() compiler autogenerated method we need to patch false positive (IAsyncStateMachine for instance) 
+                // we'll remove all MoveNext() not covered branch              
+                foreach (var document in result.Documents)
+                {
+                    List<KeyValuePair<(int, int), Branch>> branchesToRemove = new List<KeyValuePair<(int, int), Branch>>();
+                    foreach (var branch in document.Value.Branches)
+                    {
+                        //if one branch is covered we search the other one only if it's not covered
+                        if (CecilSymbolHelper.IsMoveNext(branch.Value.Method) && branch.Value.Hits > 0)
+                        {
+                            foreach (var moveNextBranch in document.Value.Branches)
+                            {
+                                if (moveNextBranch.Value.Method == branch.Value.Method && moveNextBranch.Value != branch.Value && moveNextBranch.Value.Hits == 0)
+                                {
+                                    branchesToRemove.Add(moveNextBranch);
+                                }
+                            }
+                        }
+                    }
+                    foreach (var branchToRemove in branchesToRemove)
+                    {
+                        document.Value.Branches.Remove(branchToRemove.Key);
+                    }
                 }
 
                 InstrumentationHelper.DeleteHitsFile(result.HitsFilePath);
             }
+
+            foreach (var resultToRemove in resultsToRemove)
+            {
+                _results.Remove(resultToRemove);
+            }
         }
     }
 }

src/coverlet.msbuild.tasks/InstrumentationTask.cs

@@ -13,6 +13,7 @@ public class InstrumentationTask : Task
         private string _include;
         private string _excludeByFile;
         private string _mergeWith;
+        private bool _excludeNonCalledFiles;
 
         internal static Coverage Coverage
         {
@@ -50,15 +51,20 @@ public string MergeWith
             set { _mergeWith = value; }
         }
 
+        public bool ExcludeNonCalledFiles
+        {
+            get { return _excludeNonCalledFiles; }
+            set { _excludeNonCalledFiles = value;  }
+        }
+
         public override bool Execute()
         {
             try
             {
                 var excludedSourceFiles = _excludeByFile?.Split(',');
                 var excludeFilters = _exclude?.Split(',');
                 var includeFilters = _include?.Split(',');
-
-                _coverage = new Coverage(_path, excludeFilters, includeFilters, excludedSourceFiles, _mergeWith);
+                _coverage = new Coverage(_path, excludeFilters, includeFilters, excludedSourceFiles, _mergeWith, _excludeNonCalledFiles);
                 _coverage.PrepareModules();
             }
             catch (Exception ex)

src/coverlet.msbuild/coverlet.msbuild.props

@@ -9,5 +9,6 @@
     <MergeWith Condition="$(MergeWith) == ''"></MergeWith>
     <Threshold Condition="$(Threshold) == ''">0</Threshold>
     <ThresholdType Condition="$(ThresholdType) == ''">line,branch,method</ThresholdType>
+	<ExcludeNonCalledFiles Condition="$(ExcludeNonCalledFiles) == ''">false</ExcludeNonCalledFiles>
   </PropertyGroup>
 </Project>

src/coverlet.msbuild/coverlet.msbuild.targets

@@ -10,6 +10,7 @@
       Exclude="$(Exclude)"
       ExcludeByFile="$(ExcludeByFile)"
       MergeWith="$(MergeWith)"
+	  ExcludeNonCalledFiles="$(ExcludeNonCalledFiles)"
       Path="$(TargetPath)" />
   </Target>
 
@@ -20,6 +21,7 @@
       Exclude="$(Exclude)"
       ExcludeByFile="$(ExcludeByFile)"
       MergeWith="$(MergeWith)"
+	  ExcludeNonCalledFiles="$(ExcludeNonCalledFiles)"
       Path="$(TargetPath)" />
   </Target>
 

test/coverlet.core.tests/CoverageTests.cs

@@ -1,18 +1,15 @@
 using System;
 using System.IO;
-
 using Xunit;
-using Moq;
-
-using Coverlet.Core;
-using System.Collections.Generic;
 
 namespace Coverlet.Core.Tests
 {
     public class CoverageTests
     {
-        [Fact]
-        public void TestCoverage()
+        [Theory]
+        [InlineData(false)]
+        [InlineData(true)]
+        public void TestCoverage(bool excludeNonCalledFilesValue)
         {
             string module = GetType().Assembly.Location;
             string pdb = Path.Combine(Path.GetDirectoryName(module), Path.GetFileNameWithoutExtension(module) + ".pdb");
@@ -22,17 +19,24 @@ public void TestCoverage()
             File.Copy(module, Path.Combine(directory.FullName, Path.GetFileName(module)), true);
             File.Copy(pdb, Path.Combine(directory.FullName, Path.GetFileName(pdb)), true);
 
-            // TODO: Find a way to mimick hits
+            // TODO: Find a way to mimic hits
 
-            // Since Coverage only instruments dependancies, we need a fake module here
+            // Since Coverage only instruments dependencies, we need a fake module here
             var testModule = Path.Combine(directory.FullName, "test.module.dll");
 
-            var coverage = new Coverage(testModule, Array.Empty<string>(), Array.Empty<string>(), Array.Empty<string>(), string.Empty);
+            var coverage = new Coverage(testModule, Array.Empty<string>(), Array.Empty<string>(), Array.Empty<string>(), string.Empty, excludeNonCalledFilesValue);
             coverage.PrepareModules();
 
             var result = coverage.GetCoverageResult();
 
-            Assert.NotEmpty(result.Modules);
+            if (excludeNonCalledFilesValue)
+            {
+                Assert.Empty(result.Modules);
+            }
+            else
+            {
+                Assert.NotEmpty(result.Modules);
+            }
 
             directory.Delete(true);
         }