✨ Add JSONC language support for comment parsing and traceability

Adds jsonc language support, also checks .json files if they start with a comment (see jsonc.org).

Signed-off-by: Florian Roks <florian.roks@mercedes-benz.com>

Author: floroks

docs/source/components/analyse.rst

@@ -47,7 +47,7 @@ Limitations
 
 **Current Limitations:**
 
-- **Language Support**: C/C++ (``//``, ``/* */``), C# (``//``, ``/* */``, ``///``), Python (``#``), YAML (``#``), Rust (``//``, ``/* */``, ``///``) and Go (``//``, ``/* */``) comment styles are supported
+- **Language Support**: C/C++ (``//``, ``/* */``), C# (``//``, ``/* */``, ``///``), Python (``#``), YAML (``#``), Rust (``//``, ``/* */``, ``///``), Go (``//``, ``/* */``) and JSONC (``//``, ``/* */``) comment styles are supported
 - **Single Comment Style**: Each analysis run processes only one comment style at a time
 
 Extraction Examples

docs/source/components/configuration.rst

@@ -271,7 +271,7 @@ Specifies the comment syntax style used in the source code files. This determine
 
 **Type:** ``str``
 **Default:** ``"cpp"``
-**Supported values:** ``"cpp"``, ``"python"``, ``"cs"``, ``"yaml"``, ``"rust"``, ``"go"``
+**Supported values:** ``"cpp"``, ``"python"``, ``"cs"``, ``"yaml"``, ``"rust"``, ``"go"``, ``"jsonc"``
 
 .. code-block:: toml
 
@@ -316,10 +316,16 @@ Specifies the comment syntax style used in the source code files. This determine
        ``//!`` (inner doc comments)
      - ``.rs``
    * - Go
-     - ``"go"``
-     - ``//`` (single-line),
-       ``/* */`` (multi-line)
-     - ``.go``
+      - ``"go"``
+      - ``//`` (single-line),
+        ``/* */`` (multi-line)
+      - ``.go``
+   * - JSON with Comments (JSONC)
+      - ``"jsonc"``
+      - ``//`` (single-line),
+        ``/* */`` (multi-line)
+      - ``.jsonc`` (always); ``.json`` only when the file opens with a comment
+        (e.g. the mode line ``// -*- mode: jsonc -*-``)
 
 .. note:: Future versions may support additional programming languages.
 

docs/source/components/features.rst

@@ -207,6 +207,33 @@ Features
    .. fault:: Sphinx-codelinks halucinates traceability objects in Go
       :id: FAULT_GO_2
 
+.. feature:: JSONC Language Support
+   :id: FE_JSONC
+
+   Support for defining traceability objects in JSON with Comments (JSONC) files.
+
+   The JSONC parser leverages tree-sitter to identify and extract single-line (``//``)
+   and multi-line (``/* */``) comments from JSON data, associating each marker with the
+   surrounding data structure such as the key/value pair, array item, or object it
+   annotates.
+
+   ``.jsonc`` files are always parsed as JSONC. A ``.json`` file is only treated as JSONC
+   when it opens with a comment (e.g. the mode line ``// -*- mode: jsonc -*-``), following
+   the `JSONC filename convention <https://jsonc.org/#filename-extension>`_.
+
+   Key capabilities:
+
+   * Detection of inline and leading comments
+   * Association of comments with key/value pairs and array items
+   * Support for both ``//`` and ``/* */`` comment styles
+   * Opt-in handling of ``.json`` files via a leading comment
+
+   .. fault:: Traceability objects are not detected in JSONC
+      :id: FAULT_JSONC_1
+
+   .. fault:: Sphinx-codelinks hallucinates traceability objects in JSONC
+      :id: FAULT_JSONC_2
+
 .. feature:: Customized comment styles
    :id: FE_CMT
 

pyproject.toml

@@ -31,6 +31,7 @@ dependencies = [
   "tree-sitter-yaml>=0.7.1",
   "tree-sitter-rust>=0.23.0",
   "tree-sitter-go>=0.23.0",
+  "tree-sitter-json>=0.24.8",
 ]
 
 [build-system]

src/sphinx_codelinks/analyse/utils.py

@@ -36,6 +36,8 @@
         "type_declaration",
         "type_spec",
     },
+    # @JSONC Scope Node Types, IMPL_JSONC_2, impl, [FE_JSONC]
+    CommentType.jsonc: {"pair", "object", "array", "document"},
 }
 
 logger = get_logger(__name__)
@@ -65,6 +67,19 @@
 GO_QUERY = """
     (comment) @comment
 """
+JSONC_QUERY = """(comment) @comment"""
+
+# JSON value node types that can be associated with a comment.
+JSON_STRUCTURE_TYPES = {
+    "pair",
+    "object",
+    "array",
+    "string",
+    "number",
+    "true",
+    "false",
+    "null",
+}
 
 
 def is_text_file(filepath: Path, sample_size: int = 2048) -> bool:
@@ -82,7 +97,7 @@ def is_text_file(filepath: Path, sample_size: int = 2048) -> bool:
         return False
 
 
-# @Tree-sitter parser initialization for multiple languages, IMPL_LANG_1, impl, [FE_C_SUPPORT, FE_CPP, FE_PY, FE_YAML, FE_RUST, FE_GO]
+# @Tree-sitter parser initialization for multiple languages, IMPL_LANG_1, impl, [FE_C_SUPPORT, FE_CPP, FE_PY, FE_YAML, FE_RUST, FE_GO, FE_JSONC]
 def init_tree_sitter(comment_type: CommentType) -> tuple[Parser, Query]:
     if comment_type == CommentType.cpp:
         import tree_sitter_cpp  # noqa: PLC0415
@@ -114,6 +129,11 @@ def init_tree_sitter(comment_type: CommentType) -> tuple[Parser, Query]:
 
         parsed_language = Language(tree_sitter_go.language())
         query = Query(parsed_language, GO_QUERY)
+    elif comment_type == CommentType.jsonc:
+        import tree_sitter_json  # noqa: PLC0415
+
+        parsed_language = Language(tree_sitter_json.language())
+        query = Query(parsed_language, JSONC_QUERY)
     else:
         raise ValueError(f"Unsupported comment style: {comment_type}")
     parser = Parser(parsed_language)
@@ -213,8 +233,11 @@ def find_yaml_next_structure(node: TreeSitterNode) -> TreeSitterNode | None:
     return None
 
 
-def find_yaml_prev_sibling_on_same_row(node: TreeSitterNode) -> TreeSitterNode | None:
-    """Find a previous named sibling that is on the same row as the comment."""
+def find_prev_sibling_on_same_row(node: TreeSitterNode) -> TreeSitterNode | None:
+    """Find a previous named sibling that is on the same row as the comment.
+
+    Grammar-agnostic: used to detect inline comments in both YAML and JSONC.
+    """
     comment_row = node.start_point.row
     current = node.prev_named_sibling
 
@@ -235,7 +258,7 @@ def find_yaml_prev_sibling_on_same_row(node: TreeSitterNode) -> TreeSitterNode |
 def find_yaml_associated_structure(node: TreeSitterNode) -> TreeSitterNode | None:
     """Find the YAML structure (key-value pair, list item, etc.) associated with a comment."""
     # First, check if this is an inline comment by looking for a previous sibling on the same row
-    prev_sibling_same_row = find_yaml_prev_sibling_on_same_row(node)
+    prev_sibling_same_row = find_prev_sibling_on_same_row(node)
     if prev_sibling_same_row:
         return prev_sibling_same_row
 
@@ -254,6 +277,35 @@ def find_yaml_associated_structure(node: TreeSitterNode) -> TreeSitterNode | Non
     return None
 
 
+def find_jsonc_associated_structure(node: TreeSitterNode) -> TreeSitterNode | None:
+    """Find the JSON structure (key/value pair, value, list item) for a comment.
+
+    JSON is data rather than code, so association follows the same intent as YAML:
+    an inline comment belongs to the value on its row, a leading comment belongs to
+    the following structure, otherwise it belongs to the enclosing structure.
+    """
+    # Inline comment: a value/pair on the same row, before the comment
+    prev_sibling_same_row = find_prev_sibling_on_same_row(node)
+    if prev_sibling_same_row:
+        return prev_sibling_same_row
+
+    # Leading comment: the next structure following the comment
+    current = node.next_named_sibling
+    while current:
+        if current.type in JSON_STRUCTURE_TYPES:
+            return current
+        current = current.next_named_sibling
+
+    # Otherwise: the enclosing structure
+    parent = node.parent
+    while parent:
+        if parent.type in {"pair", "object", "array"}:
+            return parent
+        parent = parent.parent
+
+    return None
+
+
 def find_associated_scope(
     node: TreeSitterNode, comment_type: CommentType = CommentType.cpp
 ) -> TreeSitterNode | None:
@@ -262,6 +314,10 @@ def find_associated_scope(
         # YAML uses different structure association logic
         return find_yaml_associated_structure(node)
 
+    if comment_type == CommentType.jsonc:
+        # JSONC uses data-aware structure association logic
+        return find_jsonc_associated_structure(node)
+
     if node.type == CommentCategory.docstring:
         # Only for python's docstring
         return find_enclosing_scope(node, comment_type)

src/sphinx_codelinks/source_discover/config.py

@@ -12,6 +12,7 @@
     "yaml": ["yml", "yaml"],
     "rust": ["rs"],
     "go": ["go"],
+    "jsonc": ["jsonc", "json"],
 }
 
 
@@ -24,6 +25,8 @@ class CommentType(str, Enum):
     rust = "rust"
     # @Support Go style comments, IMPL_GO_1, impl, [FE_GO];
     go = "go"
+    # @Support JSONC style comments, IMPL_JSONC_1, impl, [FE_JSONC];
+    jsonc = "jsonc"
 
 
 class SourceDiscoverSectionConfigType(TypedDict, total=False):

src/sphinx_codelinks/source_discover/source_discover.py

@@ -6,10 +6,28 @@
 
 from sphinx_codelinks.source_discover.config import (
     COMMENT_FILETYPE,
+    CommentType,
     SourceDiscoverConfig,
 )
 
 
+def _json_starts_with_comment(filepath: Path, sample_size: int = 256) -> bool:
+    """Return True if a ``.json`` file's first non-whitespace content is a comment.
+
+    Used to decide whether a ``.json`` file should be treated as JSONC. Per
+    https://jsonc.org/#filename-extension a ``.json`` file should only be treated as
+    JSONC when it opens with a comment (e.g. the mode line ``// -*- mode: jsonc -*-``).
+    """
+    try:
+        with filepath.open("rb") as f:
+            chunk = f.read(sample_size)
+    except OSError:
+        return False
+    # strip a leading UTF-8 BOM, then leading whitespace
+    text = chunk.removeprefix(b"\xef\xbb\xbf").lstrip()
+    return text.startswith((b"//", b"/*"))
+
+
 # @Source code file discovery with gitignore support, IMPL_DISC_1, impl, [FE_DISCOVERY, FE_CLI_DISCOVER]
 class SourceDiscover:
     def __init__(self, src_discover_config: SourceDiscoverConfig):
@@ -75,6 +93,15 @@ def _discover(self) -> list[Path]:
                 continue
             if self.file_types and filepath.suffix.lower() not in self.file_types:
                 continue
+            # @JSONC .json files require a leading comment, IMPL_JSONC_3, impl, [FE_JSONC]
+            # A plain ``.json`` file is only treated as JSONC when it opens with a
+            # comment; otherwise it is skipped under the ``jsonc`` comment type.
+            if (
+                self.src_discover_config.comment_type == CommentType.jsonc
+                and filepath.suffix.lower() == ".json"
+                and not _json_starts_with_comment(filepath)
+            ):
+                continue
             # resolve() produces canonical absolute paths; follow_links only
             # controls whether the walker descends into symlinked directories
             discovered_files.append(filepath.resolve())

tests/data/jsonc/demo.jsonc

@@ -0,0 +1,15 @@
+// -*- mode: jsonc -*-
+{
+  // @JSONC alpha implementation, IMPL_JSONC_A, impl, [REQ_JSONC_1]
+  "alpha": 1,
+  "items": [
+    "first", // @JSONC inline item, IMPL_JSONC_B, impl, [REQ_JSONC_2]
+    "second"
+  ],
+  /* Block comment with marker
+     @JSONC beta implementation, IMPL_JSONC_C, impl, [REQ_JSONC_3]
+  */
+  "beta": {
+    "nested": true
+  }
+}

tests/data/jsonc/plain.json

@@ -0,0 +1,3 @@
+{
+  "value": 42
+}

tests/data/jsonc/with_modeline.json

@@ -0,0 +1,5 @@
+// -*- mode: jsonc -*-
+{
+  // @JSONC modeline file, IMPL_JSONC_D, impl, [REQ_JSONC_4]
+  "value": 42
+}