feat: add Dart language support

* feat: add Dart language support

Add tree-sitter-based parsing for Dart source files (.dart), covering:
- Classes, mixins, extensions, enums, typedefs
- Top-level functions and class methods (including getters)
- /// doc comment extraction (skips past @annotations)
- @annotation decorator extraction
- Sibling-body byte range extension for full source retrieval

Dart's AST differs from other languages: function/method signatures and
bodies are sibling nodes rather than parent-child. The extractor handles
this transparently by extending byte ranges to include sibling
function_body nodes.

Includes tests, fixture file, and documentation updates.

* fix: address code review findings for Dart support

- Fix end_line not updating when extending byte range to sibling
  function_body (Dart's signature/body sibling pattern)
- Add missing "php" to search_symbols language enum (pre-existing)
- Enrich Dart fixture with mixin, extension, and getter examples
- Update LANGUAGE_SUPPORT.md notes: constructors and top-level
  constants are not indexed

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Cobdog

LANGUAGE_SUPPORT.md

@@ -11,6 +11,7 @@
 | Rust       | `.rs`         | tree-sitter-rust       | function, type (struct/enum/trait), impl, constant | `#[attr]`     | `///` and `//!` comments   | Macro-generated symbols are not visible to the parser            |
 | Java       | `.java`       | tree-sitter-java       | method, class, type (interface/enum), constant     | `@Annotation` | `/** */` Javadoc           | Deep inner-class nesting may be flattened                        |
 | PHP        | `.php`        | tree-sitter-php        | function, class, method, type (interface/trait/enum), constant | `#[Attribute]` | `/** */` PHPDoc | PHP 8+ attributes supported; language-file `<?php` tag required  |
+| Dart       | `.dart`       | tree-sitter-dart       | function, class (class/mixin/extension), method, type (enum/typedef) | `@annotation` | `///` doc comments | Constructors and top-level constants are not indexed               |
 
 ---
 

README.md

@@ -293,6 +293,7 @@ Every tool response includes a `_meta` envelope with timing, token savings, and
 | Rust       | `.rs`         | function, type, impl, constant          |
 | Java       | `.java`       | method, class, type, constant           |
 | PHP        | `.php`        | function, class, method, type, constant |
+| Dart       | `.dart`       | function, class, method, type           |
 
 See LANGUAGE_SUPPORT.md for full semantics.
 

src/jcodemunch_mcp/parser/extractor.py

@@ -47,6 +47,10 @@ def _walk_tree(
     parent_symbol: Optional[Symbol] = None
 ):
     """Recursively walk the AST and extract symbols."""
+    # Dart: function_signature inside method_signature is handled by method_signature
+    if node.type == "function_signature" and node.parent and node.parent.type == "method_signature":
+        return
+
     # Check if this node is a symbol
     if node.type in spec.symbol_node_types:
         symbol = _extract_symbol(
@@ -103,8 +107,17 @@ def _extract_symbol(
     # Extract decorators
     decorators = _extract_decorators(node, spec, source_bytes)
 
+    # Dart: function_signature/method_signature have their body as a next sibling
+    end_byte = node.end_byte
+    end_line_num = node.end_point[0] + 1
+    if node.type in ("function_signature", "method_signature"):
+        next_sib = node.next_named_sibling
+        if next_sib and next_sib.type == "function_body":
+            end_byte = next_sib.end_byte
+            end_line_num = next_sib.end_point[0] + 1
+
     # Compute content hash
-    symbol_bytes = source_bytes[node.start_byte:node.end_byte]
+    symbol_bytes = source_bytes[node.start_byte:end_byte]
     c_hash = compute_content_hash(symbol_bytes)
 
     # Create symbol
@@ -120,9 +133,9 @@ def _extract_symbol(
         decorators=decorators,
         parent=parent_symbol.id if parent_symbol else None,
         line=node.start_point[0] + 1,
-        end_line=node.end_point[0] + 1,
+        end_line=end_line_num,
         byte_offset=node.start_byte,
-        byte_length=node.end_byte - node.start_byte,
+        byte_length=end_byte - node.start_byte,
         content_hash=c_hash,
     )
 
@@ -144,7 +157,30 @@ def _extract_name(node, spec: LanguageSpec, source_bytes: bytes) -> Optional[str
                 if name_node:
                     return source_bytes[name_node.start_byte:name_node.end_byte].decode("utf-8")
         return None
-    
+
+    # Dart: mixin_declaration has identifier as direct child (no field name)
+    if node.type == "mixin_declaration":
+        for child in node.children:
+            if child.type == "identifier":
+                return source_bytes[child.start_byte:child.end_byte].decode("utf-8")
+        return None
+
+    # Dart: method_signature wraps function_signature or getter_signature
+    if node.type == "method_signature":
+        for child in node.children:
+            if child.type in ("function_signature", "getter_signature"):
+                name_node = child.child_by_field_name("name")
+                if name_node:
+                    return source_bytes[name_node.start_byte:name_node.end_byte].decode("utf-8")
+        return None
+
+    # Dart: type_alias name is the first type_identifier child
+    if node.type == "type_alias":
+        for child in node.children:
+            if child.type == "type_identifier":
+                return source_bytes[child.start_byte:child.end_byte].decode("utf-8")
+        return None
+
     if node.type not in spec.name_fields:
         return None
 
@@ -231,10 +267,12 @@ def _strip_quotes(text: str) -> str:
 def _extract_preceding_comments(node, source_bytes: bytes) -> str:
     """Extract comments that immediately precede a node."""
     comments = []
-    
-    # Walk backwards through siblings
+
+    # Walk backwards through siblings, skipping past annotations/decorators
     prev = node.prev_named_sibling
-    while prev and prev.type in ("comment", "line_comment", "block_comment"):
+    while prev and prev.type in ("annotation", "marker_annotation"):
+        prev = prev.prev_named_sibling
+    while prev and prev.type in ("comment", "line_comment", "block_comment", "documentation_comment"):
         comment_text = source_bytes[prev.start_byte:prev.end_byte].decode("utf-8")
         comments.insert(0, comment_text)
         prev = prev.prev_named_sibling

src/jcodemunch_mcp/parser/languages.py

@@ -54,6 +54,7 @@ class LanguageSpec:
     ".rs": "rust",
     ".java": "java",
     ".php": "php",
+    ".dart": "dart",
 }
 
 
@@ -277,6 +278,37 @@ class LanguageSpec:
 )
 
 
+# Dart specification
+DART_SPEC = LanguageSpec(
+    ts_language="dart",
+    symbol_node_types={
+        "function_signature": "function",
+        "class_definition": "class",
+        "mixin_declaration": "class",
+        "enum_declaration": "type",
+        "extension_declaration": "class",
+        "method_signature": "method",
+        "type_alias": "type",
+    },
+    name_fields={
+        "function_signature": "name",
+        "class_definition": "name",
+        "enum_declaration": "name",
+        "extension_declaration": "name",
+        # mixin_declaration, method_signature, type_alias: special-cased in extractor
+    },
+    param_fields={
+        "function_signature": "parameters",
+    },
+    return_type_fields={},
+    docstring_strategy="preceding_comment",
+    decorator_node_type="annotation",
+    container_node_types=["class_definition", "mixin_declaration", "extension_declaration"],
+    constant_patterns=[],
+    type_patterns=["type_alias", "enum_declaration"],
+)
+
+
 # Language registry
 LANGUAGE_REGISTRY = {
     "python": PYTHON_SPEC,
@@ -286,4 +318,5 @@ class LanguageSpec:
     "rust": RUST_SPEC,
     "java": JAVA_SPEC,
     "php": PHP_SPEC,
+    "dart": DART_SPEC,
 }

src/jcodemunch_mcp/server.py

@@ -212,7 +212,7 @@ async def list_tools() -> list[Tool]:
                     "language": {
                         "type": "string",
                         "description": "Optional filter by language",
-                        "enum": ["python", "javascript", "typescript", "go", "rust", "java"]
+                        "enum": ["python", "javascript", "typescript", "go", "rust", "java", "php", "dart"]
                     },
                     "max_results": {
                         "type": "integer",

tests/fixtures/dart/sample.dart

@@ -0,0 +1,38 @@
+/// User service for managing users.
+class UserService {
+  /// Get user by ID.
+  String getUser(int userId) {
+    return 'user-$userId';
+  }
+
+  /// Delete a user.
+  bool deleteUser(int userId) {
+    return true;
+  }
+
+  /// Whether the service is ready.
+  bool get isReady => true;
+}
+
+/// Scrollable behavior.
+mixin Scrollable on UserService {
+  /// Scroll to offset.
+  void scrollTo(double offset) {}
+}
+
+/// Authenticate a token.
+bool authenticate(String token) {
+  return token.isNotEmpty;
+}
+
+/// Status of a request.
+enum Status { pending, active, done }
+
+/// Helpers for String manipulation.
+extension StringExt on String {
+  /// Whether the string is blank.
+  bool get isBlank => trim().isEmpty;
+}
+
+/// JSON map alias.
+typedef JsonMap = Map<String, dynamic>;

tests/test_hardening.py

@@ -322,6 +322,7 @@ class TestDeterminism:
         ("go", "sample.go"),
         ("rust", "sample.rs"),
         ("java", "Sample.java"),
+        ("dart", "sample.dart"),
     ])
     def test_deterministic_ids_and_hashes(self, language, filename):
         content, fname = _fixture(language, filename)

tests/test_languages.py

@@ -259,3 +259,110 @@ def test_parse_php():
     assert enum is not None
     assert enum.kind == "type"
 
+
+DART_SOURCE = '''
+/// Greet a user by name.
+String greet(String name) {
+  return 'Hello, $name!';
+}
+
+/// A simple calculator.
+class Calculator {
+  /// Add two numbers.
+  int add(int a, int b) {
+    return a + b;
+  }
+
+  /// Whether the result is positive.
+  bool get isPositive => true;
+}
+
+/// Scrollable behavior for widgets.
+mixin Scrollable on Calculator {
+  /// Scroll to offset.
+  void scrollTo(double offset) {}
+}
+
+/// Status of a task.
+enum Status { pending, active, done }
+
+/// Helpers for String manipulation.
+extension StringExt on String {
+  /// Whether the string is blank.
+  bool get isBlank => trim().isEmpty;
+}
+
+/// A JSON map alias.
+typedef JsonMap = Map<String, dynamic>;
+
+/// An abstract repository.
+abstract class Repository {
+  /// Get all items.
+  @override
+  Future<List<String>> getAll() {
+    return Future.value([]);
+  }
+}
+'''
+
+
+def test_parse_dart():
+    """Test Dart parsing."""
+    symbols = parse_file(DART_SOURCE, "app.dart", "dart")
+
+    # Top-level function
+    func = next((s for s in symbols if s.name == "greet"), None)
+    assert func is not None
+    assert func.kind == "function"
+    assert "Greet a user by name" in func.docstring
+
+    # Class
+    cls = next((s for s in symbols if s.name == "Calculator"), None)
+    assert cls is not None
+    assert cls.kind == "class"
+    assert "simple calculator" in cls.docstring
+
+    # Method
+    method = next((s for s in symbols if s.name == "add"), None)
+    assert method is not None
+    assert method.kind == "method"
+    assert "Add two numbers" in method.docstring
+
+    # Getter
+    getter = next((s for s in symbols if s.name == "isPositive"), None)
+    assert getter is not None
+    assert getter.kind == "method"
+
+    # Mixin
+    mixin = next((s for s in symbols if s.name == "Scrollable"), None)
+    assert mixin is not None
+    assert mixin.kind == "class"
+
+    # Enum
+    enum = next((s for s in symbols if s.name == "Status"), None)
+    assert enum is not None
+    assert enum.kind == "type"
+
+    # Extension
+    ext = next((s for s in symbols if s.name == "StringExt"), None)
+    assert ext is not None
+    assert ext.kind == "class"
+
+    # Typedef
+    typedef = next((s for s in symbols if s.name == "JsonMap"), None)
+    assert typedef is not None
+    assert typedef.kind == "type"
+
+    # Abstract class with @override decorator
+    repo = next((s for s in symbols if s.name == "Repository"), None)
+    assert repo is not None
+    assert repo.kind == "class"
+    repo_method = next((s for s in symbols if s.name == "getAll"), None)
+    assert repo_method is not None
+    assert repo_method.kind == "method"
+    assert "@override" in repo_method.decorators
+
+    # Qualified names
+    assert method.qualified_name == "Calculator.add"
+    assert getter.qualified_name == "Calculator.isPositive"
+