Fix unhandled exception in /getItem and /getTargetResult for items with illegal path characters (#12841)

Copilot · JanProvaznik · YuliiaKovalova · web-flow · commit 49a6fd48e744 · 2026-01-05T14:12:08.000Z
### Context `/getItem` and `/getTargetResult` throw an unhandled `InvalidOperationException` when serializing items whose item specs contain illegal path characters (e.g., compiler command line flags from ClangTidy's `GetCompileCommands` target). The JSON output formatter iterates over all metadata names including built-in metadata like `FullPath`, `Directory`, etc. When `GetMetadata()` is called on these, it attempts path computation which fails for non-path item specs. ### Changes Made - Wrapped metadata retrieval in `JsonOutputFormatter.cs` with try-catch for `InvalidOperationException` - Added `TryGetMetadata` and `TryGetMetadataValue` helper methods that return empty string on failure - Applied fix to all three affected methods: `AddTargetResultsInJsonFormat`, `AddItemInstancesInJsonFormat`, `AddItemsInJsonFormat` - Exception handling catches all `InvalidOperationException` instances to ensure compatibility across all locales (error messages are localized) ### Testing Added `GetTargetResultWithIllegalPathCharacters` test that verifies both `/getTargetResult` and `/getItem` succeed with items containing compiler flags as item specs. ### Notes On Linux, the test shows the path-like metadata is still computed (since `/` is valid in paths). On Windows, these would return empty strings. The key fix is preventing the unhandled exception crash. The exception handling is intentionally broad (catching all `InvalidOperationException` without message filtering) to ensure the fix works correctly in all locales, as error messages from MSBuild are localized and checking for specific English text would fail in non-English environments.  <details> <summary>Original prompt</summary> ---- *This section details on the original issue you should resolve* <issue_title>[Unhandled Exception]: /getItem and /getTargetResult fail for target GetCompileCommands</issue_title> <issue_description>### Issue Description There is an uncaught exception when trying to access certain information from the GetCompileCommands target (from ClangTidy), in particular `/getTargetResult:GetCompileCommands` and `/getTargetResult:GetCompileCommands` ### Steps to Reproduce [tidytest.zip](https://github.com/user-attachments/files/22645381/tidytest.zip) Run either of the following commands (You could also run with target `/t:ClangTidy` for the same result) ``` msbuild tidytest.vcxproj /t:GetCompileCommands /getTargetResult:GetCompileCommands msbuild tidytest.vcxproj /t:GetCompileCommands /getItem:CompileCommands ``` I expect to get a json formatted target result or item. ### Actual Behavior I get the following error when building ``` C:\Users\rp0656\source\repos\tidytest>msbuild tidytest.vcxproj /t:GetCompileCommands /getTargetResult:GetCompileCommands MSBUILD : error MSB1025: An internal failure occurred while running MSBuild. System.InvalidOperationException: The item metadata "%(FullPath)" cannot be applied to the path "/c /nologo /W3 /WX- /diagnostics:column /Od /D _DEBUG /D _CONSOLE /D _UNICODE /D UNICODE /EHsc /RTC1 /MDd /GS /fp:precise /permissive- /Fa"tidytest\x64\Debug\\" /Fo"tidytest\x64\Debug\\" /Gd --target=amd64-pc-windows-msvc /TP". Illegal characters in path. at Microsoft.Build.Shared.ErrorUtilities.ThrowInvalidOperation(String resourceName, Object[] args) at Microsoft.Build.Shared.FileUtilities.ItemSpecModifiers.GetItemSpecModifier(String currentDirectory, String itemSpec, String definingProjectEscaped, String modifier, String& fullPath) at Microsoft.Build.Evaluation.BuiltInMetadata.GetMetadataValueEscaped(String currentDirectory, String evaluatedIncludeBeforeWildcardExpansionEscaped, String evaluatedIncludeEscaped, String definingProjectEscaped, String name, String& fullPath) at Microsoft.Build.Execution.ProjectItemInstance.TaskItem.GetBuiltInMetadataEscaped(String name) at Microsoft.Build.Execution.ProjectItemInstance.TaskItem.GetMetadataEscaped(String metadataName) at Microsoft.Build.Execution.ProjectItemInstance.TaskItem.GetMetadata(String metadataName) at Microsoft.Build.CommandLine.JsonOutputFormatter.AddTargetResultsInJsonFormat(String[] targetNames, BuildResult result) at Microsoft.Build.CommandLine.MSBuildApp.OutputBuildInformationInJson(BuildResult result, String[] getProperty, String[] getItem, String[] getTargetResult, ILogger[] loggers, ExitType exitType, TextWriter outputStream) at Microsoft.Build.CommandLine.MSBuildApp.Execute(String commandLine) Unhandled Exception: System.InvalidOperationException: The item metadata "%(FullPath)" cannot be applied to the path "/c /nologo /W3 /WX- /diagnostics:column /Od /D _DEBUG /D _CONSOLE /D _UNICODE /D UNICODE /EHsc /RTC1 /MDd /GS /fp:precise /permissive- /Fa"tidytest\x64\Debug\\" /Fo"tidytest\x64\Debug\\" /Gd --target=amd64-pc-windows-msvc /TP". Illegal characters in path. at Microsoft.Build.Shared.ErrorUtilities.ThrowInvalidOperation(String resourceName, Object[] args) at Microsoft.Build.Shared.FileUtilities.ItemSpecModifiers.GetItemSpecModifier(String currentDirectory, String itemSpec, String definingProjectEscaped, String modifier, String& fullPath) at Microsoft.Build.Evaluation.BuiltInMetadata.GetMetadataValueEscaped(String currentDirectory, String evaluatedIncludeBeforeWildcardExpansionEscaped, String evaluatedIncludeEscaped, String definingProjectEscaped, String name, String& fullPath) at Microsoft.Build.Execution.ProjectItemInstance.TaskItem.GetBuiltInMetadataEscaped(String name) at Microsoft.Build.Execution.ProjectItemInstance.TaskItem.GetMetadataEscaped(String metadataName) at Microsoft.Build.Execution.ProjectItemInstance.TaskItem.GetMetadata(String metadataName) at Microsoft.Build.CommandLine.JsonOutputFormatter.AddTargetResultsInJsonFormat(String[] targetNames, BuildResult result) at Microsoft.Build.CommandLine.MSBuildApp.OutputBuildInformationInJson(BuildResult result, String[] getProperty, String[] getItem, String[] getTargetResult, ILogger[] loggers, ExitType exitType, TextWriter outputStream) at Microsoft.Build.CommandLine.MSBuildApp.Execute(String commandLine) at Microsoft.Build.CommandLine.MSBuildApp.Main() ``` ### Analysis The error suggests that it is trying to interpret the flags of the compile commands as a path, which causes an error when it can't be resolved. The function `%(FullPath)` is used, though it is not clear to me exactly where, but my best guess is it used on a variable that is supposed to just be the path to `cl`, but has been extended with flags. See the clang tidy targets file at something similar to `C:\Program Files\Microsoft Visual Studio\2022\Enterprise\MSBuild\Microsoft\VC\v170\Microsoft.Cpp.ClangTidy.targets` ### Versions & Co... </details> - Fixes #12589  --- ✨ Let Copilot coding agent [set things up for you](https://github.com/dotnet/msbuild/issues/new?title=✨+Set+up+Copilot+instructions&body=Configure%20instructions%20for%20this%20repository%20as%20documented%20in%20%5BBest%20practices%20for%20Copilot%20coding%20agent%20in%20your%20repository%5D%28https://gh.io/copilot-coding-agent-tips%29%2E%0A%0A%3COnboard%20this%20repo%3E&assignees=copilot) — coding agent works faster and does higher quality work when set up for your repo. --------- Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com> Co-authored-by: JanProvaznik <25267098+JanProvaznik@users.noreply.github.com> Co-authored-by: Jan Provazník <janprovaznik@microsoft.com> Co-authored-by: YuliiaKovalova <95473390+YuliiaKovalova@users.noreply.github.com>
diff --git a/src/MSBuild.UnitTests/XMake_Tests.cs b/src/MSBuild.UnitTests/XMake_Tests.cs
@@ -888,6 +888,38 @@ public void GetStarOutputsToFileIfRequested(string extraSwitch, string result)
             result.ShouldContain("MSB1068");
         }
 
+        /// <summary>
+        /// Regression test for issue where getTargetResult/getItem would throw an unhandled exception
+        /// when the item spec contained illegal path characters (e.g. compiler command line flags).
+        /// </summary>
+        [Theory]
+        [InlineData("-getTargetResult:GetCompileCommands", "\"Result\": \"Success\"")]
+        [InlineData("-getItem:CompileCommands", "\"Identity\":")]
+        public void GetTargetResultWithIllegalPathCharacters(string extraSwitch, string expectedContent)
+        {
+            using TestEnvironment env = TestEnvironment.Create();
+            // Create a project that mimics the ClangTidy target - it outputs items with illegal path characters
+            // (compiler command line flags) as the item spec.
+            TransientTestFile project = env.CreateFile("testProject.csproj", @"
+<Project>
+  <ItemGroup>
+    <CompileCommands Include=""/c /nologo /W3 /WX- /diagnostics:column /Od /D _DEBUG"" />
+  </ItemGroup>
+
+  <Target Name=""GetCompileCommands"" Returns=""@(CompileCommands)"">
+    <ItemGroup>
+      <CompileCommands Include=""/c /fp:precise /permissive- /Fa&quot;Debug\\&quot; /Fo&quot;Debug\\&quot; /Gd --target=amd64-pc-windows-msvc /TP"" />
+    </ItemGroup>
+  </Target>
+</Project>
+");
+            string results = RunnerUtilities.ExecMSBuild($" {project.Path} /t:GetCompileCommands {extraSwitch}", out bool success);
+            // The build should succeed instead of throwing an unhandled exception
+            success.ShouldBeTrue(results);
+            // The output should contain the expected content
+            results.ShouldContain(expectedContent);
+        }
+
         [Theory]
         [InlineData(true)]
         [InlineData(false)]
diff --git a/src/MSBuild/JsonOutputFormatter.cs b/src/MSBuild/JsonOutputFormatter.cs
@@ -67,7 +67,7 @@ internal void AddItemInstancesInJsonFormat(string[] itemNames, ProjectInstance p
                             continue;
                         }
 
-                        jsonItem[metadatumName] = item.GetMetadataValue(metadatumName);
+                        jsonItem[metadatumName] = TryGetMetadataValue(item, metadatumName);
                     }
 
                     itemArray.Add(jsonItem);
@@ -108,7 +108,7 @@ internal void AddItemsInJsonFormat(string[] itemNames, Project project)
                             continue;
                         }
 
-                        jsonItem[metadatumName] = item.GetMetadataValue(metadatumName);
+                        jsonItem[metadatumName] = TryGetMetadataValue(item, metadatumName);
                     }
 
                     itemArray.Add(jsonItem);
@@ -147,7 +147,7 @@ internal void AddTargetResultsInJsonFormat(string[] targetNames, BuildResult res
                             continue;
                         }
 
-                        jsonItem[metadatumName] = item.GetMetadata(metadatumName);
+                        jsonItem[metadatumName] = TryGetMetadata(item, metadatumName);
                     }
 
                     outputArray.Add(jsonItem);
@@ -159,5 +159,62 @@ internal void AddTargetResultsInJsonFormat(string[] targetNames, BuildResult res
 
             _topLevelNode["TargetResults"] = targetResultsNode;
         }
+
+        /// <summary>
+        /// Attempts to get metadata from an ITaskItem. If the metadata is a built-in metadata
+        /// (like FullPath, Directory, etc.) and the item spec contains illegal path characters,
+        /// this will catch the InvalidOperationException and return an empty string.
+        /// </summary>
+        private static string TryGetMetadata(ITaskItem item, string metadataName)
+        {
+            try
+            {
+                return item.GetMetadata(metadataName);
+            }
+            catch (InvalidOperationException)
+            {
+                // Built-in metadata like FullPath, Directory, etc. require path computation.
+                // If the item spec contains illegal path characters, return empty string.
+                return string.Empty;
+            }
+        }
+
+        /// <summary>
+        /// Attempts to get metadata value from a ProjectItemInstance. If the metadata is a built-in metadata
+        /// (like FullPath, Directory, etc.) and the item spec contains illegal path characters,
+        /// this will catch the InvalidOperationException and return an empty string.
+        /// </summary>
+        private static string TryGetMetadataValue(ProjectItemInstance item, string metadataName)
+        {
+            try
+            {
+                return item.GetMetadataValue(metadataName);
+            }
+            catch (InvalidOperationException)
+            {
+                // Built-in metadata like FullPath, Directory, etc. require path computation.
+                // If the item spec contains illegal path characters, return empty string.
+                return string.Empty;
+            }
+        }
+
+        /// <summary>
+        /// Attempts to get metadata value from a ProjectItem. If the metadata is a built-in metadata
+        /// (like FullPath, Directory, etc.) and the item spec contains illegal path characters,
+        /// this will catch the InvalidOperationException and return an empty string.
+        /// </summary>
+        private static string TryGetMetadataValue(ProjectItem item, string metadataName)
+        {
+            try
+            {
+                return item.GetMetadataValue(metadataName);
+            }
+            catch (InvalidOperationException)
+            {
+                // Built-in metadata like FullPath, Directory, etc. require path computation.
+                // If the item spec contains illegal path characters, return empty string.
+                return string.Empty;
+            }
+        }
     }
 }
