Fix cache hit in CodeAnalysisRuleSetPredictor

Directory.Packages.props

@@ -5,6 +5,7 @@
     <MSBuildPackageVersion>17.11.4</MSBuildPackageVersion>
   </PropertyGroup>
   <ItemGroup>
+    <PackageVersion Include="Microsoft.Bcl.HashCode" Version="6.0.0" Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' " />
     <PackageVersion Include="Microsoft.Build" Version="$(MSBuildPackageVersion)" />
     <PackageVersion Include="Microsoft.Build.Framework" Version="$(MSBuildPackageVersion)" />
     <PackageVersion Include="Microsoft.Build.Utilities.Core" Version="$(MSBuildPackageVersion)" />

src/BuildPrediction/Microsoft.Build.Prediction.csproj

@@ -9,6 +9,7 @@
     <Description>A library to predict inputs and outputs of MSBuild projects</Description>
   </PropertyGroup>
   <ItemGroup>
+    <PackageReference Include="Microsoft.Bcl.HashCode" Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' " />
     <PackageReference Include="Microsoft.Build" />
     <PackageReference Include="Microsoft.Build.Framework" />
     <PackageReference Include="Microsoft.Build.Utilities.Core" />

src/BuildPrediction/Predictors/CodeAnalysisRuleSetPredictor.cs

@@ -29,7 +29,7 @@ public sealed class CodeAnalysisRuleSetPredictor : IProjectPredictor
         private readonly List<string> _emptyList = new List<string>(0);
 
         // Often rulesets are reused across projects, so keep a cache to avoid parsing the same ruleset over and over.
-        private readonly ConcurrentDictionary<string, HashSet<string>> _cachedInputs = new ConcurrentDictionary<string, HashSet<string>>(StringComparer.OrdinalIgnoreCase);
+        private readonly ConcurrentDictionary<RuleSetCacheKey, HashSet<string>> _cachedInputs = new ConcurrentDictionary<RuleSetCacheKey, HashSet<string>>();
 
         /// <inheritdoc/>
         public void PredictInputsAndOutputs(
@@ -60,7 +60,7 @@ public void PredictInputsAndOutputs(
             }
         }
 
-        // Based on resolution logic from: https://github.com/Microsoft/msbuild/blob/master/src/Tasks/ResolveCodeAnalysisRuleSet.cs
+        // Based on resolution logic from: https://github.com/Microsoft/msbuild/blob/main/src/Tasks/ResolveCodeAnalysisRuleSet.cs
         private static string GetResolvedRuleSetPath(
             string ruleSet,
             List<string> ruleSetDirectories,
@@ -148,7 +148,8 @@ private HashSet<string> ParseRuleset(
                 return _emptySet;
             }
 
-            if (_cachedInputs.TryGetValue(ruleSetPath, out HashSet<string> cachedResults))
+            RuleSetCacheKey cacheKey = new RuleSetCacheKey(ruleSetPath, ruleSetDirectories);
+            if (_cachedInputs.TryGetValue(cacheKey, out HashSet<string> cachedResults))
             {
                 return cachedResults;
             }
@@ -241,7 +242,7 @@ private HashSet<string> ParseRuleset(
                 // As described above, do not cache intermediate results inside a cycle.
                 if (!isInCycle)
                 {
-                    _cachedInputs.TryAdd(ruleSetPath, results);
+                    _cachedInputs.TryAdd(cacheKey, results);
                 }
 
                 return results;
@@ -252,5 +253,53 @@ private HashSet<string> ParseRuleset(
                 return _emptySet;
             }
         }
+
+        private readonly record struct RuleSetCacheKey
+        {
+            public RuleSetCacheKey(string ruleSetPath, IReadOnlyList<string> ruleSetDirectories)
+            {
+                RuleSetPath = ruleSetPath;
+                RuleSetDirectories = new List<string>(ruleSetDirectories);
+            }
+
+            public string RuleSetPath { get; }
+
+            public List<string> RuleSetDirectories { get; }
+
+            public bool Equals(RuleSetCacheKey other)
+            {
+                if (!PathComparer.Instance.Equals(RuleSetPath, other.RuleSetPath))
+                {
+                    return false;
+                }
+
+                if (RuleSetDirectories.Count != other.RuleSetDirectories.Count)
+                {
+                    return false;
+                }
+
+                for (int i = 0; i < RuleSetDirectories.Count; i++)
+                {
+                    if (!PathComparer.Instance.Equals(RuleSetDirectories[i], other.RuleSetDirectories[i]))
+                    {
+                        return false;
+                    }
+                }
+
+                return true;
+            }
+
+            public override int GetHashCode()
+            {
+                int hash = PathComparer.Instance.GetHashCode(RuleSetPath);
+
+                foreach (string directory in RuleSetDirectories)
+                {
+                    hash = HashCode.Combine(hash, PathComparer.Instance.GetHashCode(directory));
+                }
+
+                return hash;
+            }
+        }
     }
 }

src/BuildPredictionTests/Predictors/CodeAnalysisRuleSetPredictorTests.cs

@@ -84,6 +84,28 @@ public void RuleSetIsCached()
             AssertInputs("a.ruleset", expectedInputs);
         }
 
+        [Fact]
+        public void RuleSetIsCacheMissOnDifferentCodeAnalysisDirectories()
+        {
+            var rulesetA = CreateRuleSetFile("a.ruleset")
+                .WithInclude("b.ruleset")
+                .WriteToDisk();
+            var rulesetB = CreateRuleSetFile("foo\\b.ruleset")
+                .WriteToDisk();
+
+            var expectedInputs = new[]
+            {
+                rulesetA.FullPath,
+            };
+            AssertInputs("a.ruleset", expectedInputs);
+
+            expectedInputs = [
+                rulesetA.FullPath,
+                rulesetB.FullPath,
+            ];
+            AssertInputs("a.ruleset", expectedInputs, [Path.GetDirectoryName(rulesetB.FullPath)]);
+        }
+
         [Fact]
         public void RuleSetWithRuleHintPaths()
         {
@@ -296,7 +318,7 @@ public void RuleSetWithComplexCycle()
             AssertInputs("a2.ruleset", expectedResultsInCycleBCD.Union(new[] { rulesetA2.FullPath }).ToList());
         }
 
-        private void AssertInputs(string ruleSetPath, IList<string> expectedInputs)
+        private void AssertInputs(string ruleSetPath, IList<string> expectedInputs, IList<string> codeAnalysisRuleSetDirectories = null)
         {
             ProjectRootElement projectRootElement = ProjectRootElement.Create(Path.Combine(_rootDir, "project.proj"));
             if (ruleSetPath != null)
@@ -305,6 +327,11 @@ private void AssertInputs(string ruleSetPath, IList<string> expectedInputs)
                 projectRootElement.AddProperty(CodeAnalysisRuleSetPredictor.CodeAnalysisRuleSetPropertyName, ruleSetPath);
             }
 
+            if (codeAnalysisRuleSetDirectories != null)
+            {
+                projectRootElement.AddProperty(CodeAnalysisRuleSetPredictor.CodeAnalysisRuleSetDirectoriesPropertyName, string.Join(";", codeAnalysisRuleSetDirectories));
+            }
+
             var projectInstance = TestHelpers.CreateProjectInstanceFromRootElement(projectRootElement);
 
             var expectedInputFiles = expectedInputs?