feat: Add clangd integration tests and documentation

.github/workflows/go.yml

@@ -131,3 +131,39 @@ jobs:
 
       - name: Run TypeScript integration tests
         run: go test ./integrationtests/tests/typescript/...
+
+  clangd-integration-tests:
+    name: Clangd Integration Tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: "1.24"
+          check-latest: true
+          cache: true
+
+      - name: Install LLVM, Clang and bear
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y clang-16 llvm-16 clangd-16 bear
+
+      - name: Verify Clangd Installation
+        run: |
+          sudo ln -s /usr/bin/clangd-16 /usr/bin/clangd
+          clangd-16 --version
+          clangd --version
+
+      - name: Create compile commands
+        run: |
+          cd integrationtests/workspaces/clangd
+          bear -- make
+          cd ../../../..
+
+      - name: Run Clangd definition tests
+        run: go test ./integrationtests/tests/clangd/definition...
+
+      - name: Run Clangd diagnostics tests
+        run: go test ./integrationtests/tests/clangd/diagnostics...

.gitignore

@@ -4,6 +4,12 @@ mcp-language-server
 # Test output
 test-output/
 *.diff
+integrationtests/workspaces/clangd/compile_commands.json
+integrationtests/workspaces/clangd/src/*.o
+integrationtests/workspaces/clangd/clean_program
+integrationtests/workspaces/clangd/program
+integrationtests/workspaces/clangd/.cache
+
 
 # Temporary files
 *~

README.md

@@ -124,6 +124,37 @@ This is an [MCP](https://modelcontextprotocol.io/introduction) server that runs
 </pre>
   </div>
 </details>
+<details>
+  <summary>C/C++ (clangd)</summary>
+  <div>
+    <p><strong>Install clangd</strong>: Download prebuilt binaries from the <a href="https://github.com/clangd/clangd/releases">official LLVM releases page</a> or install via your system's package manager (e.g., <code>apt install clangd</code>, <code>brew install clangd</code>).</p>
+    <p><strong>Configure your MCP client</strong>: This will be different but similar for each client. For Claude Desktop, add the following to <code>~/Library/Application\\ Support/Claude/claude_desktop_config.json</code></p>
+
+<pre>
+{
+  "mcpServers": {
+    "language-server": {
+      "command": "mcp-language-server",
+      "args": [
+        "--workspace",
+        "/Users/you/dev/yourproject/",
+        "--lsp",
+        "/path/to/your/clangd_binary",
+        "--",
+        "--compile-commands-dir=/path/to/yourproject/build_or_compile_commands_dir"
+      ]
+    }
+  }
+}
+</pre>
+    <p><strong>Note</strong>:</p>
+    <ul>
+      <li>Replace <code>/path/to/your/clangd_binary</code> with the actual path to your clangd executable.</li>
+      <li><code>--compile-commands-dir</code> should point to the directory containing your <code>compile_commands.json</code> file (e.g., <code>./build</code>, <code>./cmake-build-debug</code>).</li>
+      <li>Ensure <code>compile_commands.json</code> is generated for your project for clangd to work effectively.</li>
+    </ul>
+  </div>
+</details>
 <details>
   <summary>Other</summary>
   <div>

integrationtests/snapshots/clangd/definition/class.snap

@@ -0,0 +1,16 @@
+---
+
+Symbol: TestClass
+/TEST_OUTPUT/workspace/clangd/src/consumer.cpp
+Range: L7:C1 - L15:C2
+
+ 7|class TestClass {
+ 8| public:
+ 9|  /**
+10|   * @brief A method that takes an integer parameter.
+11|   *
+12|   * @param param The integer parameter to be processed.
+13|   */
+14|  void method(int param) { helperFunction(); }
+15|};
+

integrationtests/snapshots/clangd/definition/constant.snap

@@ -0,0 +1,8 @@
+---
+
+Symbol: TEST_CONSTANT
+/TEST_OUTPUT/workspace/clangd/src/helper.cpp
+Range: L4:C1 - L4:C29
+
+4|const int TEST_CONSTANT = 42;
+

integrationtests/snapshots/clangd/definition/foobar.snap

@@ -0,0 +1,11 @@
+---
+
+Symbol: foo_bar
+/TEST_OUTPUT/workspace/src/main.cpp
+Range: L5:C1 - L8:C2
+
+5|void foo_bar() {
+6|  std::cout << "Hello, World!" << std::endl;
+7|  return;
+8|}
+

integrationtests/snapshots/clangd/definition/helperFunction.snap

@@ -0,0 +1,8 @@
+---
+
+Symbol: helperFunction
+/TEST_OUTPUT/workspace/clangd/src/helper.cpp
+Range: L7:C1 - L7:C71
+
+7|void helperFunction() { std::cout << "Helper function" << std::endl; }
+

integrationtests/snapshots/clangd/definition/method.snap

@@ -0,0 +1,16 @@
+---
+
+Symbol: method
+/TEST_OUTPUT/workspace/clangd/src/consumer.cpp
+Range: L7:C1 - L15:C2
+
+ 7|class TestClass {
+ 8| public:
+ 9|  /**
+10|   * @brief A method that takes an integer parameter.
+11|   *
+12|   * @param param The integer parameter to be processed.
+13|   */
+14|  void method(int param) { helperFunction(); }
+15|};
+

integrationtests/snapshots/clangd/definition/struct.snap

@@ -0,0 +1,10 @@
+---
+
+Symbol: TestStruct
+/TEST_OUTPUT/workspace/clangd/src/types.cpp
+Range: L6:C1 - L8:C2
+
+6|struct TestStruct {
+7|  int value;
+8|};
+

integrationtests/snapshots/clangd/definition/type.snap

@@ -0,0 +1,8 @@
+---
+
+Symbol: TestType
+/TEST_OUTPUT/workspace/clangd/src/types.cpp
+Range: L10:C1 - L10:C21
+
+10|using TestType = int;
+

integrationtests/snapshots/clangd/definition/variable.snap

@@ -0,0 +1,8 @@
+---
+
+Symbol: TEST_VARIABLE
+/TEST_OUTPUT/workspace/clangd/src/helper.cpp
+Range: L5:C1 - L5:C24
+
+5|int TEST_VARIABLE = 100;  // A test variable used for integration testing purposes.
+

integrationtests/snapshots/clangd/diagnostics/clean.snap

@@ -0,0 +1 @@
+/TEST_OUTPUT/workspace/src/clean.cpp

integrationtests/snapshots/clangd/diagnostics/unreachable.snap

@@ -0,0 +1,11 @@
+/TEST_OUTPUT/workspace/src/main.cpp
+Diagnostics in File: 1
+WARNING at L14:C3: Code will never be executed (Source: clang, Code: -Wunreachable-code)
+
+10|int main() {
+...
+12|  return 0;
+13|
+14|  foo_bar();
+15|
+16|  // Intentional error: unreachable code

integrationtests/snapshots/clangd/hover/class-method.snap

@@ -0,0 +1,10 @@
+instance-method method
+
+→ void
+Parameters:
+- int param
+@brief A method that takes an integer parameter.
+@param param The integer parameter to be processed.
+
+// In TestClass
+public: void method(int param)

integrationtests/snapshots/clangd/hover/class-type.snap

@@ -0,0 +1,5 @@
+class TestClass
+
+Size: 1 byte
+
+class TestClass {}

integrationtests/snapshots/clangd/hover/function-definition-cpp.snap

@@ -0,0 +1,5 @@
+function helperFunction
+
+→ void
+
+void helperFunction()

integrationtests/snapshots/clangd/hover/function-main.snap

@@ -0,0 +1,6 @@
+function foo_bar
+
+→ void
+FooBar is a simple function for testing
+
+void foo_bar()

integrationtests/snapshots/clangd/hover/no-hover-info-comment.snap

@@ -0,0 +1,2 @@
+No hover information available for this position on the following line:
+// FooBar is a simple function for testing

integrationtests/snapshots/clangd/hover/outside-file.snap

@@ -0,0 +1 @@
+No hover information available for this position on the following line:

integrationtests/snapshots/clangd/hover/variable.snap

@@ -0,0 +1,7 @@
+variable TEST_VARIABLE
+
+Type: int
+Value = 100 (0x64)
+A test variable used for integration testing purposes.
+
+int TEST_VARIABLE = 100

integrationtests/snapshots/clangd/references/foobar-function-references.snap

@@ -0,0 +1,15 @@
+---
+
+/TEST_OUTPUT/workspace/clangd/src/main.cpp
+References in File: 1
+At: L14:C3
+
+10|int main() {
+11|  helperFunction();
+12|  return 0;
+13|
+14|  foo_bar();
+15|
+16|  // Intentional error: unreachable code
+17|  std::cout << "This is unreachable" << std::endl;
+18|}

integrationtests/snapshots/clangd/references/helper-function-references.snap

@@ -0,0 +1,31 @@
+---
+
+/TEST_OUTPUT/workspace/clangd/src/consumer.cpp
+References in File: 1
+At: L14:C28
+
+ 9|  /**
+10|   * @brief A method that takes an integer parameter.
+11|   *
+12|   * @param param The integer parameter to be processed.
+13|   */
+14|  void method(int param) { helperFunction(); }
+15|};
+
+---
+
+/TEST_OUTPUT/workspace/clangd/src/main.cpp
+References in File: 1
+At: L11:C3
+
+ 6|  std::cout << "Hello, World!" << std::endl;
+ 7|  return;
+ 8|}
+ 9|
+10|int main() {
+11|  helperFunction();
+12|  return 0;
+13|
+14|  foo_bar();
+15|
+16|  // Intentional error: unreachable code

integrationtests/tests/clangd/README.md

@@ -0,0 +1,19 @@
+\
+# Clangd Integration Tests
+
+This directory contains integration tests for `clangd`, the C/C++ language server.
+
+## Prerequisites
+
+Before running these tests, you must generate the `compile_commands.json` file in the `integrationtests/workspaces/clangd` directory. This can typically be done by navigating to that directory and running a tool like `bear` with your build command (e.g., `bear -- make`).
+
+The GitHub Actions workflow for these tests uses the following command from the root of the repository:
+```bash
+cd integrationtests/workspaces/clangd
+bear -- make
+cd ../../../..
+```
+
+## Clangd Version
+
+These tests are currently run against **clangd version 16**. While they may pass with other versions of clangd, compatibility is not guaranteed.