C#: Fix the cs/path-combine code quality issues in the extractor.

michaelnebel · michaelnebel · commit f82fedf56aac · 2026-06-17T16:03:08.000+02:00
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyContainer.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyContainer.cs
@@ -50,7 +50,7 @@ public void Add(string package, string dependency)
                 return;
             }
 
-            var path = Path.Combine(p, ParseFilePath(d));
+            var path = Path.Join(p, ParseFilePath(d));
             Paths.Add(path);
             Packages.Add(GetPackageName(p));
         }
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyManager.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DependencyManager.cs
@@ -75,7 +75,7 @@ public DependencyManager(string srcDir, ILogger logger)
                 }
             }
 
-            this.diagnosticsWriter = new DiagnosticsStream(Path.Combine(
+            this.diagnosticsWriter = new DiagnosticsStream(Path.Join(
                 diagDirEnv ?? "",
                 $"dependency-manager-{DateTime.UtcNow:yyyyMMddHHmm}-{Environment.ProcessId}.jsonc"));
             this.sourceDir = new DirectoryInfo(srcDir);
@@ -327,7 +327,7 @@ private void AddNetFrameworkDlls(ISet<AssemblyLookupLocation> dllLocations, ISet
         private void RemoveNugetPackageReference(string packagePrefix, ISet<AssemblyLookupLocation> dllLocations)
         {
             var packageFolder = nugetPackageRestorer.PackageDirectory.DirInfo.FullName.ToLowerInvariant();
-            var packagePathPrefix = Path.Combine(packageFolder, packagePrefix.ToLowerInvariant());
+            var packagePathPrefix = Path.Join(packageFolder, packagePrefix.ToLowerInvariant());
             var toRemove = dllLocations.Where(s => s.Path.StartsWith(packagePathPrefix, StringComparison.InvariantCultureIgnoreCase));
             foreach (var path in toRemove)
             {
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DotNet.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DotNet.cs
@@ -31,7 +31,7 @@ private DotNet(IDotNetCliInvoker dotnetCliInvoker, ILogger logger, bool runDotne
             }
         }
 
-        private DotNet(ILogger logger, string? dotNetPath, TemporaryDirectory tempWorkingDirectory, DependabotProxy? dependabotProxy) : this(new DotNetCliInvoker(logger, Path.Combine(dotNetPath ?? string.Empty, "dotnet"), dependabotProxy), logger, dotNetPath is null, tempWorkingDirectory) { }
+        private DotNet(ILogger logger, string? dotNetPath, TemporaryDirectory tempWorkingDirectory, DependabotProxy? dependabotProxy) : this(new DotNetCliInvoker(logger, Path.Join(dotNetPath ?? string.Empty, "dotnet"), dependabotProxy), logger, dotNetPath is null, tempWorkingDirectory) { }
 
         internal static IDotNet Make(IDotNetCliInvoker dotnetCliInvoker, ILogger logger, bool runDotnetInfo) => new DotNet(dotnetCliInvoker, logger, runDotnetInfo);
 
@@ -73,7 +73,7 @@ private string GetRestoreArgs(RestoreSettings restoreSettings)
                 var path = ".empty";
                 if (tempWorkingDirectory != null)
                 {
-                    path = Path.Combine(tempWorkingDirectory.ToString(), "emptyFakeDotnetRoot");
+                    path = Path.Join(tempWorkingDirectory.ToString(), "emptyFakeDotnetRoot");
                     Directory.CreateDirectory(path);
                 }
 
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DotNetVersion.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/DotNetVersion.cs
@@ -12,7 +12,7 @@ internal record DotNetVersion : IComparable<DotNetVersion>
         private string FullVersion =>
             version.ToString();
 
-        public string FullPath => Path.Combine(dir, FullVersion);
+        public string FullPath => Path.Join(dir, FullVersion);
 
         /**
          * The full path to the reference assemblies for this runtime.
@@ -33,7 +33,7 @@ public string? FullPathReferenceAssemblies
                 {
                     directories[^2] = "packs";
                     directories[^1] = $"{directories[^1]}.Ref";
-                    return Path.Combine(string.Join(Path.DirectorySeparatorChar, directories), FullVersion, "ref");
+                    return Path.Join(string.Join(Path.DirectorySeparatorChar, directories), FullVersion, "ref");
                 }
                 return null;
             }
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetExeWrapper.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetExeWrapper.cs
@@ -46,7 +46,7 @@ public NugetExeWrapper(FileProvider fileProvider, DependencyDirectory packageDir
                 if (HasNoPackageSource() && useDefaultFeed())
                 {
                     // We only modify or add a top level nuget.config file
-                    nugetConfigPath = Path.Combine(fileProvider.SourceDir.FullName, "nuget.config");
+                    nugetConfigPath = Path.Join(fileProvider.SourceDir.FullName, "nuget.config");
                     try
                     {
                         if (File.Exists(nugetConfigPath))
@@ -55,7 +55,7 @@ public NugetExeWrapper(FileProvider fileProvider, DependencyDirectory packageDir
 
                             do
                             {
-                                backupNugetConfig = Path.Combine(tempFolderPath, Path.GetRandomFileName());
+                                backupNugetConfig = Path.Join(tempFolderPath, Path.GetRandomFileName());
                             }
                             while (File.Exists(backupNugetConfig));
                             File.Copy(nugetConfigPath, backupNugetConfig, true);
@@ -123,7 +123,7 @@ private string ResolveNugetExe()
             var nugetPath = FileUtils.FindProgramOnPath(executableName);
             if (nugetPath is not null)
             {
-                nugetPath = Path.Combine(nugetPath, executableName);
+                nugetPath = Path.Join(nugetPath, executableName);
                 logger.LogInfo($"Using nuget.exe from PATH: {nugetPath}");
                 return nugetPath;
             }
@@ -133,8 +133,8 @@ private string ResolveNugetExe()
 
         private string DownloadNugetExe(string sourceDir)
         {
-            var directory = Path.Combine(sourceDir, ".nuget");
-            var nuget = Path.Combine(directory, "nuget.exe");
+            var directory = Path.Join(sourceDir, ".nuget");
+            var nuget = Path.Join(directory, "nuget.exe");
 
             // Nuget.exe already exists in the .nuget directory.
             if (File.Exists(nuget))
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackageRestorer.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/NugetPackageRestorer.cs
@@ -209,7 +209,7 @@ public HashSet<AssemblyLookupLocation> Restore()
 
             var paths = dependencies
                 .Paths
-                .Select(d => Path.Combine(PackageDirectory.DirInfo.FullName, d))
+                .Select(d => Path.Join(PackageDirectory.DirInfo.FullName, d))
                 .ToList();
             assemblyLookupLocations.UnionWith(paths.Select(p => new AssemblyLookupLocation(p)));
 
@@ -527,7 +527,7 @@ private void RestoreProjects(IEnumerable<string> projects, HashSet<string> reach
             var sb = new StringBuilder();
             fallbackNugetFeeds.ForEach((feed, index) => sb.AppendLine($"<add key=\"feed{index}\" value=\"{feed}\" />"));
 
-            var nugetConfigPath = Path.Combine(folderPath, "nuget.config");
+            var nugetConfigPath = Path.Join(folderPath, "nuget.config");
             logger.LogInfo($"Creating fallback nuget.config file {nugetConfigPath}.");
             File.WriteAllText(nugetConfigPath,
                 $"""
@@ -1052,15 +1052,15 @@ public void Dispose()
         /// </summary>
         private static string ComputeTempDirectoryPath(string subfolderName)
         {
-            return Path.Combine(FileUtils.GetTemporaryWorkingDirectory(out _), subfolderName);
+            return Path.Join(FileUtils.GetTemporaryWorkingDirectory(out _), subfolderName);
         }
 
         /// <summary>
         /// Computes a unique temporary directory path based on the source directory and the subfolder name.
         /// </summary>
         private static string ComputeTempDirectoryPath(string srcDir, string subfolderName)
         {
-            return Path.Combine(FileUtils.GetTemporaryWorkingDirectory(out _), FileUtils.ComputeHash(srcDir), subfolderName);
+            return Path.Join(FileUtils.GetTemporaryWorkingDirectory(out _), FileUtils.ComputeHash(srcDir), subfolderName);
         }
     }
 }
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/Runtime.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/Runtime.cs
@@ -79,7 +79,7 @@ private IEnumerable<string> DesktopRuntimes
 
                 var monoPath = FileUtils.FindProgramOnPath(Win32.IsWindows() ? "mono.exe" : "mono");
                 string[] monoDirs = monoPath is not null
-                    ? [Path.GetFullPath(Path.Combine(monoPath, "..", "lib", "mono")), monoPath]
+                    ? [Path.GetFullPath(Path.Join(monoPath, "..", "lib", "mono")), monoPath]
                     : ["/usr/lib/mono", "/usr/local/mono", "/usr/local/bin/mono", @"C:\Program Files\Mono\lib\mono"];
 
                 var monoDir = monoDirs.FirstOrDefault(Directory.Exists);
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/Sdk.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/Sdk.cs
@@ -63,7 +63,7 @@ private static HashSet<DotNetVersion> ParseSdks(IList<string> listed)
                 return null;
             }
 
-            var path = Path.Combine(version.FullPath, "Roslyn", "bincore", "csc.dll");
+            var path = Path.Join(version.FullPath, "Roslyn", "bincore", "csc.dll");
             logger.LogDebug($"Source generator CSC: '{path}'");
             if (!File.Exists(path))
             {
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/DotnetSourceGeneratorWrapper/DotnetSourceGeneratorWrapper.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/DotnetSourceGeneratorWrapper/DotnetSourceGeneratorWrapper.cs
@@ -41,10 +41,10 @@ public IEnumerable<string> RunSourceGenerator(IEnumerable<string> additionalFile
                     .Replace('\\', '/'); // Ensure we're generating the same hash regardless of the OS
                 var name = FileUtils.ComputeHash($"{relativePathToCsProj}\n{this.GetType().Name}");
                 using var tempDir = new TemporaryDirectory(Path.Join(FileUtils.GetTemporaryWorkingDirectory(out _), "source-generator"), "source generator temporary", logger);
-                var analyzerConfigPath = Path.Combine(tempDir.DirInfo.FullName, $"{name}.txt");
-                var dllPath = Path.Combine(tempDir.DirInfo.FullName, $"{name}.dll");
-                var cscArgsPath = Path.Combine(tempDir.DirInfo.FullName, $"{name}.rsp");
-                var outputFolder = Path.Combine(targetDir, name);
+                var analyzerConfigPath = Path.Join(tempDir.DirInfo.FullName, $"{name}.txt");
+                var dllPath = Path.Join(tempDir.DirInfo.FullName, $"{name}.dll");
+                var cscArgsPath = Path.Join(tempDir.DirInfo.FullName, $"{name}.rsp");
+                var outputFolder = Path.Join(targetDir, name);
                 Directory.CreateDirectory(outputFolder);
                 logger.LogInfo("Producing analyzer config content.");
                 GenerateAnalyzerConfig(additionalFiles, csprojFile, analyzerConfigPath);
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/DotnetSourceGeneratorWrapper/Razor.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/DotnetSourceGeneratorWrapper/Razor.cs
@@ -21,7 +21,7 @@ public Razor(Sdk sdk, IDotNet dotNet, ILogger logger) : base(sdk, dotNet, logger
                 throw new Exception("No SDK path available.");
             }
 
-            SourceGeneratorFolder = Path.Combine(sdkPath, "Sdks", "Microsoft.NET.Sdk.Razor", "source-generators");
+            SourceGeneratorFolder = Path.Join(sdkPath, "Sdks", "Microsoft.NET.Sdk.Razor", "source-generators");
             this.logger.LogInfo($"Razor source generator folder: {SourceGeneratorFolder}");
             if (!Directory.Exists(SourceGeneratorFolder))
             {
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/ImplicitUsingsGenerator.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/ImplicitUsingsGenerator.cs
@@ -50,7 +50,7 @@ protected override IEnumerable<string> Run()
             if (usings.Count > 0)
             {
                 var tempDir = GetTemporaryWorkingDirectory("implicitUsings");
-                var path = Path.Combine(tempDir, "GlobalUsings.g.cs");
+                var path = Path.Join(tempDir, "GlobalUsings.g.cs");
                 using (var writer = new StreamWriter(path))
                 {
                     writer.WriteLine("// <auto-generated/>");
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/ResxGenerator.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/ResxGenerator.cs
@@ -32,7 +32,7 @@ public ResxGenerator(
                 var nugetFolder = nugetPackageRestorer.TryRestore("Microsoft.CodeAnalysis.ResxSourceGenerator");
                 if (nugetFolder is not null)
                 {
-                    sourceGeneratorFolder = System.IO.Path.Combine(nugetFolder, "analyzers", "dotnet", "cs");
+                    sourceGeneratorFolder = System.IO.Path.Join(nugetFolder, "analyzers", "dotnet", "cs");
                 }
             }
             catch (Exception e)
diff --git a/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/SourceGeneratorBase.cs b/csharp/extractor/Semmle.Extraction.CSharp.DependencyFetching/SourceGenerators/SourceGeneratorBase.cs
@@ -35,7 +35,7 @@ public IEnumerable<string> Generate()
         /// </summary>
         protected string GetTemporaryWorkingDirectory(string subfolder)
         {
-            var temp = Path.Combine(tempWorkingDirectory.ToString(), subfolder);
+            var temp = Path.Join(tempWorkingDirectory.ToString(), subfolder);
             Directory.CreateDirectory(temp);
 
             return temp;
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Extractor/CompilerVersion.cs b/csharp/extractor/Semmle.Extraction.CSharp/Extractor/CompilerVersion.cs
@@ -67,7 +67,7 @@ public CompilerVersion(Options options)
                     return;
                 }
 
-                var mscorlibExists = File.Exists(Path.Combine(compilerDir, "mscorlib.dll"));
+                var mscorlibExists = File.Exists(Path.Join(compilerDir, "mscorlib.dll"));
 
                 if (specifiedFramework is null && mscorlibExists)
                 {
@@ -107,7 +107,7 @@ private void SkipExtractionBecause(string reason)
         /// <summary>
         /// The file csc.rsp.
         /// </summary>
-        private string CscRsp => Path.Combine(FrameworkPath, csc_rsp);
+        private string CscRsp => Path.Join(FrameworkPath, csc_rsp);
 
         /// <summary>
         /// Should we skip extraction?
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Extractor/Context.cs b/csharp/extractor/Semmle.Extraction.CSharp/Extractor/Context.cs
@@ -680,7 +680,7 @@ public string TryAdjustRelativeMappedFilePath(string mappedToPath, string mapped
             {
                 try
                 {
-                    var fullPath = Path.GetFullPath(Path.Combine(Path.GetDirectoryName(mappedFromPath)!, mappedToPath));
+                    var fullPath = Path.GetFullPath(Path.Join(Path.GetDirectoryName(mappedFromPath)!, mappedToPath));
                     ExtractionContext.Logger.LogDebug($"Found relative path in line mapping: '{mappedToPath}', interpreting it as '{fullPath}'");
 
                     mappedToPath = fullPath;
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Extractor/CsProjFile.cs b/csharp/extractor/Semmle.Extraction.CSharp/Extractor/CsProjFile.cs
@@ -159,7 +159,7 @@ private static (string[] csFiles, string[] references, string[] projectReference
                 return null;
             }
 
-            return Path.GetFullPath(Path.Combine(projDir?.FullName ?? string.Empty, Path.DirectorySeparatorChar == '/' ? file.Replace("\\", "/") : file));
+            return Path.GetFullPath(Path.Join(projDir?.FullName ?? string.Empty, Path.DirectorySeparatorChar == '/' ? file.Replace("\\", "/") : file));
         }
 
         private readonly string[] references;
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Extractor/Extractor.cs b/csharp/extractor/Semmle.Extraction.CSharp/Extractor/Extractor.cs
@@ -210,7 +210,7 @@ static bool filter(CompilerCall compilerCall)
                             TracingAnalyser.GetOutputName(compilation, args),
                             compilation,
                             generatedSyntaxTrees,
-                            Path.Combine(compilationIdentifierPath, diagnosticName),
+                            Path.Join(compilationIdentifierPath, diagnosticName),
                             options),
                         () => { });
 
@@ -377,7 +377,7 @@ private static IEnumerable<Action> ResolveReferences(Microsoft.CodeAnalysis.Comm
                 else
                 {
                     var composed = referencePaths.Value
-                        .Select(path => Path.Combine(path, clref.Reference))
+                        .Select(path => Path.Join(path, clref.Reference))
                         .Where(path => File.Exists(path))
                         .Select(path => analyser.PathCache.GetCanonicalPath(path))
                         .FirstOrDefault();
@@ -559,13 +559,13 @@ private static ExitCode AnalyseTracing(
         /// Gets the path to the `csharp.log` file written to by the C# extractor.
         /// </summary>
         public static string GetCSharpLogPath() =>
-            Path.Combine(GetCSharpLogDirectory(), "csharp.log");
+            Path.Join(GetCSharpLogDirectory(), "csharp.log");
 
         /// <summary>
         /// Gets the path to a `csharp.{hash}.txt` file written to by the C# extractor.
         /// </summary>
         public static string GetCSharpArgsLogPath(string hash) =>
-            Path.Combine(GetCSharpLogDirectory(), $"csharp.{hash}.txt");
+            Path.Join(GetCSharpLogDirectory(), $"csharp.{hash}.txt");
 
         /// <summary>
         /// Gets a list of all `csharp.{hash}.txt` files currently written to the log directory.
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Extractor/TracingAnalyser.cs b/csharp/extractor/Semmle.Extraction.CSharp/Extractor/TracingAnalyser.cs
@@ -131,7 +131,7 @@ internal static string GetOutputName(CSharpCompilation compilation,
                 return Path.ChangeExtension(entryPointFilename, ".exe");
             }
 
-            return Path.Combine(commandLineArguments.OutputDirectory, commandLineArguments.OutputFileName);
+            return Path.Join(commandLineArguments.OutputDirectory, commandLineArguments.OutputFileName);
         }
 
         private int LogDiagnostics()
diff --git a/csharp/extractor/Semmle.Extraction.CSharp/Extractor/TrapWriter.cs b/csharp/extractor/Semmle.Extraction.CSharp/Extractor/TrapWriter.cs
@@ -61,7 +61,7 @@ public TrapWriter(ILogger logger, PathTransformer.ITransformedPath outputfile, s
                      * Although GetRandomFileName() is cryptographically secure,
                      * there's a tiny chance the file could already exists.
                      */
-                    tmpFile = Path.Combine(tempPath, Path.GetRandomFileName());
+                    tmpFile = Path.Join(tempPath, Path.GetRandomFileName());
                 }
                 while (File.Exists(tmpFile));
 
diff --git a/csharp/extractor/Semmle.Util.Tests/CanonicalPathCache.cs b/csharp/extractor/Semmle.Util.Tests/CanonicalPathCache.cs
@@ -82,13 +82,13 @@ public void CanonicalPathUNCRoot()
         [Fact]
         public void CanonicalPathMissingFile()
         {
-            Assert.Equal(Path.Combine(Directory.GetCurrentDirectory(), "NOSUCHFILE"), cache.GetCanonicalPath("NOSUCHFILE"));
+            Assert.Equal(Path.Join(Directory.GetCurrentDirectory(), "NOSUCHFILE"), cache.GetCanonicalPath("NOSUCHFILE"));
         }
 
         [Fact]
         public void CanonicalPathMissingAbsolutePath()
         {
-            Assert.Equal(Path.Combine(root, "no", "such", "file"), cache.GetCanonicalPath(Path.Combine(root, "no", "such", "file")));
+            Assert.Equal(Path.Join(root, "no", "such", "file"), cache.GetCanonicalPath(Path.Join(root, "no", "such", "file")));
 
             if (Win32.IsWindows())
                 Assert.Equal(@"C:\Windows\no\such\file", cache.GetCanonicalPath(@"C:\windOws\no\such\file"));
@@ -97,7 +97,7 @@ public void CanonicalPathMissingAbsolutePath()
         [Fact]
         public void CanonicalPathMissingRelativePath()
         {
-            Assert.Equal(Path.Combine(Directory.GetCurrentDirectory(), "NO", "SUCH"), cache.GetCanonicalPath(Path.Combine("NO", "SUCH")));
+            Assert.Equal(Path.Join(Directory.GetCurrentDirectory(), "NO", "SUCH"), cache.GetCanonicalPath(Path.Join("NO", "SUCH")));
         }
 
         [Fact]
@@ -125,7 +125,7 @@ public void CanonicalPathCorrectsCase()
         public void CanonicalPathDots()
         {
             var abcPath = Path.GetFullPath("abc");
-            Assert.Equal(abcPath, cache.GetCanonicalPath(Path.Combine("foo", ".", "..", "abc")));
+            Assert.Equal(abcPath, cache.GetCanonicalPath(Path.Join("foo", ".", "..", "abc")));
         }
 
         [Fact]
diff --git a/csharp/extractor/Semmle.Util.Tests/LongPaths.cs b/csharp/extractor/Semmle.Util.Tests/LongPaths.cs
@@ -14,20 +14,20 @@ namespace SemmleTests.Semmle.Util
     public sealed class LongPaths
     {
         private static readonly string tmpDir = Environment.GetEnvironmentVariable("TEST_TMPDIR") ?? Path.GetTempPath();
-        private static readonly string longPathDir = Path.Combine(tmpDir, "aaaaaaaaaaaaaaaaaaaaaaaaaaaa", "bbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
+        private static readonly string longPathDir = Path.Join(tmpDir, "aaaaaaaaaaaaaaaaaaaaaaaaaaaa", "bbbbbbbbbbbbbbbbbbbbbbbbbbbbb",
             "ccccccccccccccccccccccccccccccc", "ddddddddddddddddddddddddddddddddddddd", "eeeeeeeeeeeeeeeeeeeeeeeeeeeeeee", "fffffffffffffffffffffffffffffffff",
             "ggggggggggggggggggggggggggggggggggg", "hhhhhhhhhhhhhhhhhhhhhhhhhhhhhh");
 
         private static string MakeLongPath()
         {
             var uniquePostfix = Guid.NewGuid().ToString("N");
-            return Path.Combine(longPathDir, $"iiiiiiiiiiiiiiii{uniquePostfix}.txt");
+            return Path.Join(longPathDir, $"iiiiiiiiiiiiiiii{uniquePostfix}.txt");
         }
 
         private static string MakeShortPath()
         {
             var uniquePostfix = Guid.NewGuid().ToString("N");
-            return Path.Combine(tmpDir, $"test{uniquePostfix}.txt");
+            return Path.Join(tmpDir, $"test{uniquePostfix}.txt");
         }
 
         public LongPaths()
@@ -62,7 +62,7 @@ private static void WithSetUpAndTearDown(Action<string, string> test)
         [Fact]
         public void ParentDirectory()
         {
-            Assert.Equal("abc", Path.GetDirectoryName(Path.Combine("abc", "def")));
+            Assert.Equal("abc", Path.GetDirectoryName(Path.Join("abc", "def")));
             Assert.Equal(Win32.IsWindows() ? "\\" : "/", Path.GetDirectoryName($@"{Path.DirectorySeparatorChar}def"));
             Assert.Equal("", Path.GetDirectoryName(@"def"));
 
diff --git a/csharp/extractor/Semmle.Util/BuildActions.cs b/csharp/extractor/Semmle.Util/BuildActions.cs
diff --git a/csharp/extractor/Semmle.Util/CanonicalPathCache.cs b/csharp/extractor/Semmle.Util/CanonicalPathCache.cs
diff --git a/csharp/extractor/Semmle.Util/FileUtils.cs b/csharp/extractor/Semmle.Util/FileUtils.cs

Original file line number	Diff line number	Diff line change
`@@ -50,7 +50,7 @@ public void Add(string package, string dependency)`
`50`	`50`	`return;`
`51`	`51`	`}`
`52`	`52`
`53`		`- var path = Path.Combine(p, ParseFilePath(d));`
	`53`	`+ var path = Path.Join(p, ParseFilePath(d));`
`54`	`54`	`Paths.Add(path);`
`55`	`55`	`Packages.Add(GetPackageName(p));`
`56`	`56`	`}`
Original file line number	Diff line number	Diff line change
`@@ -75,7 +75,7 @@ public DependencyManager(string srcDir, ILogger logger)`
`75`	`75`	`}`
`76`	`76`	`}`
`77`	`77`
`78`		`- this.diagnosticsWriter = new DiagnosticsStream(Path.Combine(`
	`78`	`+ this.diagnosticsWriter = new DiagnosticsStream(Path.Join(`
`79`	`79`	`diagDirEnv ?? "",`
`80`	`80`	`$"dependency-manager-{DateTime.UtcNow:yyyyMMddHHmm}-{Environment.ProcessId}.jsonc"));`
`81`	`81`	`this.sourceDir = new DirectoryInfo(srcDir);`
`@@ -327,7 +327,7 @@ private void AddNetFrameworkDlls(ISet<AssemblyLookupLocation> dllLocations, ISet`
`327`	`327`	`private void RemoveNugetPackageReference(string packagePrefix, ISet<AssemblyLookupLocation> dllLocations)`
`328`	`328`	`{`
`329`	`329`	`var packageFolder = nugetPackageRestorer.PackageDirectory.DirInfo.FullName.ToLowerInvariant();`
`330`		`- var packagePathPrefix = Path.Combine(packageFolder, packagePrefix.ToLowerInvariant());`
	`330`	`+ var packagePathPrefix = Path.Join(packageFolder, packagePrefix.ToLowerInvariant());`
`331`	`331`	`var toRemove = dllLocations.Where(s => s.Path.StartsWith(packagePathPrefix, StringComparison.InvariantCultureIgnoreCase));`
`332`	`332`	`foreach (var path in toRemove)`
`333`	`333`	`{`
Original file line number	Diff line number	Diff line change
`@@ -31,7 +31,7 @@ private DotNet(IDotNetCliInvoker dotnetCliInvoker, ILogger logger, bool runDotne`
`31`	`31`	`}`
`32`	`32`	`}`
`33`	`33`
`34`		`- private DotNet(ILogger logger, string? dotNetPath, TemporaryDirectory tempWorkingDirectory, DependabotProxy? dependabotProxy) : this(new DotNetCliInvoker(logger, Path.Combine(dotNetPath ?? string.Empty, "dotnet"), dependabotProxy), logger, dotNetPath is null, tempWorkingDirectory) { }`
	`34`	`+ private DotNet(ILogger logger, string? dotNetPath, TemporaryDirectory tempWorkingDirectory, DependabotProxy? dependabotProxy) : this(new DotNetCliInvoker(logger, Path.Join(dotNetPath ?? string.Empty, "dotnet"), dependabotProxy), logger, dotNetPath is null, tempWorkingDirectory) { }`
`35`	`35`
`36`	`36`	`internal static IDotNet Make(IDotNetCliInvoker dotnetCliInvoker, ILogger logger, bool runDotnetInfo) => new DotNet(dotnetCliInvoker, logger, runDotnetInfo);`
`37`	`37`
`@@ -73,7 +73,7 @@ private string GetRestoreArgs(RestoreSettings restoreSettings)`
`73`	`73`	`var path = ".empty";`
`74`	`74`	`if (tempWorkingDirectory != null)`
`75`	`75`	`{`
`76`		`- path = Path.Combine(tempWorkingDirectory.ToString(), "emptyFakeDotnetRoot");`
	`76`	`+ path = Path.Join(tempWorkingDirectory.ToString(), "emptyFakeDotnetRoot");`
`77`	`77`	`Directory.CreateDirectory(path);`
`78`	`78`	`}`
`79`	`79`
Original file line number	Diff line number	Diff line change
`@@ -12,7 +12,7 @@ internal record DotNetVersion : IComparable<DotNetVersion>`
`12`	`12`	`private string FullVersion =>`
`13`	`13`	`version.ToString();`
`14`	`14`
`15`		`- public string FullPath => Path.Combine(dir, FullVersion);`
	`15`	`+ public string FullPath => Path.Join(dir, FullVersion);`
`16`	`16`
`17`	`17`	`/**`
`18`	`18`	`* The full path to the reference assemblies for this runtime.`
`@@ -33,7 +33,7 @@ public string? FullPathReferenceAssemblies`
`33`	`33`	`{`
`34`	`34`	`directories[^2] = "packs";`
`35`	`35`	`directories[^1] = $"{directories[^1]}.Ref";`
`36`		`- return Path.Combine(string.Join(Path.DirectorySeparatorChar, directories), FullVersion, "ref");`
	`36`	`+ return Path.Join(string.Join(Path.DirectorySeparatorChar, directories), FullVersion, "ref");`
`37`	`37`	`}`
`38`	`38`	`return null;`
`39`	`39`	`}`
Original file line number	Diff line number	Diff line change
`@@ -46,7 +46,7 @@ public NugetExeWrapper(FileProvider fileProvider, DependencyDirectory packageDir`
`46`	`46`	`if (HasNoPackageSource() && useDefaultFeed())`
`47`	`47`	`{`
`48`	`48`	`// We only modify or add a top level nuget.config file`
`49`		`- nugetConfigPath = Path.Combine(fileProvider.SourceDir.FullName, "nuget.config");`
	`49`	`+ nugetConfigPath = Path.Join(fileProvider.SourceDir.FullName, "nuget.config");`
`50`	`50`	`try`
`51`	`51`	`{`
`52`	`52`	`if (File.Exists(nugetConfigPath))`
`@@ -55,7 +55,7 @@ public NugetExeWrapper(FileProvider fileProvider, DependencyDirectory packageDir`
`55`	`55`
`56`	`56`	`do`
`57`	`57`	`{`
`58`		`- backupNugetConfig = Path.Combine(tempFolderPath, Path.GetRandomFileName());`
	`58`	`+ backupNugetConfig = Path.Join(tempFolderPath, Path.GetRandomFileName());`
`59`	`59`	`}`
`60`	`60`	`while (File.Exists(backupNugetConfig));`
`61`	`61`	`File.Copy(nugetConfigPath, backupNugetConfig, true);`
`@@ -123,7 +123,7 @@ private string ResolveNugetExe()`
`123`	`123`	`var nugetPath = FileUtils.FindProgramOnPath(executableName);`
`124`	`124`	`if (nugetPath is not null)`
`125`	`125`	`{`
`126`		`- nugetPath = Path.Combine(nugetPath, executableName);`
	`126`	`+ nugetPath = Path.Join(nugetPath, executableName);`
`127`	`127`	`logger.LogInfo($"Using nuget.exe from PATH: {nugetPath}");`
`128`	`128`	`return nugetPath;`
`129`	`129`	`}`
`@@ -133,8 +133,8 @@ private string ResolveNugetExe()`
`133`	`133`
`134`	`134`	`private string DownloadNugetExe(string sourceDir)`
`135`	`135`	`{`
`136`		`- var directory = Path.Combine(sourceDir, ".nuget");`
`137`		`- var nuget = Path.Combine(directory, "nuget.exe");`
	`136`	`+ var directory = Path.Join(sourceDir, ".nuget");`
	`137`	`+ var nuget = Path.Join(directory, "nuget.exe");`
`138`	`138`
`139`	`139`	`// Nuget.exe already exists in the .nuget directory.`
`140`	`140`	`if (File.Exists(nuget))`
Original file line number	Diff line number	Diff line change
`@@ -209,7 +209,7 @@ public HashSet<AssemblyLookupLocation> Restore()`
`209`	`209`
`210`	`210`	`var paths = dependencies`
`211`	`211`	`.Paths`
`212`		`- .Select(d => Path.Combine(PackageDirectory.DirInfo.FullName, d))`
	`212`	`+ .Select(d => Path.Join(PackageDirectory.DirInfo.FullName, d))`
`213`	`213`	`.ToList();`
`214`	`214`	`assemblyLookupLocations.UnionWith(paths.Select(p => new AssemblyLookupLocation(p)));`
`215`	`215`
`@@ -527,7 +527,7 @@ private void RestoreProjects(IEnumerable<string> projects, HashSet<string> reach`
`527`	`527`	`var sb = new StringBuilder();`
`528`	`528`	`fallbackNugetFeeds.ForEach((feed, index) => sb.AppendLine($"<add key=\"feed{index}\" value=\"{feed}\" />"));`
`529`	`529`
`530`		`- var nugetConfigPath = Path.Combine(folderPath, "nuget.config");`
	`530`	`+ var nugetConfigPath = Path.Join(folderPath, "nuget.config");`
`531`	`531`	`logger.LogInfo($"Creating fallback nuget.config file {nugetConfigPath}.");`
`532`	`532`	`File.WriteAllText(nugetConfigPath,`
`533`	`533`	`$"""`
`@@ -1052,15 +1052,15 @@ public void Dispose()`
`1052`	`1052`	`/// </summary>`
`1053`	`1053`	`private static string ComputeTempDirectoryPath(string subfolderName)`
`1054`	`1054`	`{`
`1055`		`- return Path.Combine(FileUtils.GetTemporaryWorkingDirectory(out _), subfolderName);`
	`1055`	`+ return Path.Join(FileUtils.GetTemporaryWorkingDirectory(out _), subfolderName);`
`1056`	`1056`	`}`
`1057`	`1057`
`1058`	`1058`	`/// <summary>`
`1059`	`1059`	`/// Computes a unique temporary directory path based on the source directory and the subfolder name.`
`1060`	`1060`	`/// </summary>`
`1061`	`1061`	`private static string ComputeTempDirectoryPath(string srcDir, string subfolderName)`
`1062`	`1062`	`{`
`1063`		`- return Path.Combine(FileUtils.GetTemporaryWorkingDirectory(out _), FileUtils.ComputeHash(srcDir), subfolderName);`
	`1063`	`+ return Path.Join(FileUtils.GetTemporaryWorkingDirectory(out _), FileUtils.ComputeHash(srcDir), subfolderName);`
`1064`	`1064`	`}`
`1065`	`1065`	`}`
`1066`	`1066`	`}`
Original file line number	Diff line number	Diff line change
`@@ -63,7 +63,7 @@ private static HashSet<DotNetVersion> ParseSdks(IList<string> listed)`
`63`	`63`	`return null;`
`64`	`64`	`}`
`65`	`65`
`66`		`- var path = Path.Combine(version.FullPath, "Roslyn", "bincore", "csc.dll");`
	`66`	`+ var path = Path.Join(version.FullPath, "Roslyn", "bincore", "csc.dll");`
`67`	`67`	`logger.LogDebug($"Source generator CSC: '{path}'");`
`68`	`68`	`if (!File.Exists(path))`
`69`	`69`	`{`
Original file line number	Diff line number	Diff line change
`@@ -21,7 +21,7 @@ public Razor(Sdk sdk, IDotNet dotNet, ILogger logger) : base(sdk, dotNet, logger`
`21`	`21`	`throw new Exception("No SDK path available.");`
`22`	`22`	`}`
`23`	`23`
`24`		`- SourceGeneratorFolder = Path.Combine(sdkPath, "Sdks", "Microsoft.NET.Sdk.Razor", "source-generators");`
	`24`	`+ SourceGeneratorFolder = Path.Join(sdkPath, "Sdks", "Microsoft.NET.Sdk.Razor", "source-generators");`
`25`	`25`	`this.logger.LogInfo($"Razor source generator folder: {SourceGeneratorFolder}");`
`26`	`26`	`if (!Directory.Exists(SourceGeneratorFolder))`
`27`	`27`	`{`