fix(extract): emit reference edges for TS/JS decorators

`@Component`, `@Injectable`, `@Input`, `@Inject`, `@Entity`, … produced no
edge — the `decorator` node kind was never walked. This is framework-critical
(Angular, NestJS, Vue class components, TypeORM): the decorators are the
primary signal of what a class is and does.

Decorators occur only on classes, class members, and parameters, so one pass
over each class declaration covers them. `_ts_emit_decorator_edges` emits a
`references` edge (context="decorator") from the decorated entity to the
decorator symbol:

  - class decorators -> the class. Handles both `@Deco class C` (decorator is
    a child of the class) and `@Deco export class C` (decorator sits on the
    wrapping export_statement), plus stacked decorators.
  - method decorators -> the method node. They are siblings preceding the
    `method_definition`; stacked decorators are skipped past to find it.
  - field / accessor decorators -> the class (the field is not a graph node).
  - parameter decorators (`@Inject(T)`) -> the enclosing method/constructor.

The symbol is the head identifier: `@Injectable`, the `function` of
`@Component({...})`, or the `property` of `@ns.Component()`. Targets go
through `ensure_named_node`, so a decorator defined outside the corpus
becomes a sourceless stub, consistent with type references — one per
referencing file, matching the cross-file stub disambiguation introduced
with full-path node IDs in 0.9.0.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

graphify/extract.py

@@ -3367,6 +3367,12 @@ def _extract_generic(
             callable_def_nids.add(class_nid)  # a class is callable (constructor)
             add_edge(file_nid, class_nid, "contains", line)
 
+            # TS/JS decorators on the class and its members (@Component, @Injectable,
+            # @Input, @Inject, @Entity, …). Decorators live only in class subtrees.
+            if config.ts_module in ("tree_sitter_javascript", "tree_sitter_typescript"):
+                _ts_emit_decorator_edges(node, class_nid, stem, source,
+                                         ensure_named_node, add_edge)
+
             if config.ts_module == "tree_sitter_swift" and any(
                 c.type == "extension" for c in node.children
             ):
@@ -9913,6 +9919,125 @@ _JS_PRIMITIVE_TYPES = frozenset({
 })
 
 
+def _ts_decorator_name(deco_node, source: bytes) -> str | None:
+    """Return the head symbol of a TS `decorator` node.
+
+    `@Injectable` -> the identifier; `@Component({...})` / `@Input()` -> the
+    `function` of the call_expression; `@ng.Component()` / `@core.Injectable` ->
+    the `property` of the member_expression (the imported symbol, not the
+    namespace alias).
+    """
+    for child in deco_node.children:
+        if not child.is_named:
+            continue
+        target = child
+        if target.type == "call_expression":
+            target = target.child_by_field_name("function") or target
+        if target.type == "member_expression":
+            prop = target.child_by_field_name("property")
+            return _read_text(prop, source) if prop else None
+        if target.type == "identifier":
+            return _read_text(target, source)
+        return None
+    return None
+
+
+def _ts_method_name(method_node, source: bytes) -> str | None:
+    """Name of a `method_definition`, matching the id the function-types branch
+    builds (`_make_id(class_nid, name)`)."""
+    name_node = method_node.child_by_field_name("name")
+    return _read_text(name_node, source) if name_node else None
+
+
+def _ts_descendant_decorators(node) -> list:
+    """Collect `decorator` nodes under `node` (e.g. parameter decorators inside a
+    method's formal_parameters, or a field's own decorator), without crossing into
+    a nested class or a nested method, which own their own decorators."""
+    out: list = []
+
+    def rec(n, top: bool) -> None:
+        for child in n.children:
+            ct = child.type
+            if ct == "decorator":
+                out.append(child)
+            elif ct in ("class_declaration", "abstract_class_declaration"):
+                continue
+            elif ct == "method_definition" and not top:
+                continue
+            else:
+                rec(child, False)
+
+    rec(node, True)
+    return out
+
+
+def _ts_emit_decorator_edges(class_node, class_nid: str, stem: str, source: bytes,
+                             ensure_named_node, add_edge) -> None:
+    """Emit `references` edges (context="decorator") from a class and its members
+    to the symbols of the TS decorators applied to them.
+
+    Decorators only occur on classes, class members, and parameters, so a single
+    pass over the class declaration covers them. Members that are graph nodes
+    (methods, incl. the constructor) own their decorators and their parameter
+    decorators; members that are not nodes (fields, parameters) attribute to the
+    enclosing class. Targets go through `ensure_named_node`, so a decorator
+    imported from another module (the common case — `@Component` from
+    `@angular/core`) becomes a sourceless stub the corpus rewire collapses onto
+    the real definition.
+    """
+    def emit(deco_node, owner_nid: str) -> None:
+        name = _ts_decorator_name(deco_node, source)
+        if not name:
+            return
+        line = deco_node.start_point[0] + 1
+        target = ensure_named_node(name, line)
+        if target != owner_nid:
+            add_edge(owner_nid, target, "references", line, context="decorator")
+
+    # Class-level decorators: direct children of the class node (`@Deco class C`),
+    # plus — when exported (`@Deco export class C`) — the decorators that sit on
+    # the wrapping export_statement, before the class.
+    for child in class_node.children:
+        if child.type == "decorator":
+            emit(child, class_nid)
+    parent = class_node.parent
+    if parent is not None and parent.type == "export_statement":
+        for child in parent.children:
+            if child.type == "decorator":
+                emit(child, class_nid)
+            elif child.type in ("class_declaration", "abstract_class_declaration"):
+                break
+
+    # Member decorators inside the class body.
+    body = next((c for c in class_node.children if c.type == "class_body"), None)
+    if body is None:
+        return
+    for member in body.children:
+        mt = member.type
+        if mt == "decorator":
+            # A method decorator is a sibling preceding the method; skip past any
+            # stacked decorators to find it.
+            owner = class_nid
+            sib = member.next_named_sibling
+            while sib is not None and sib.type == "decorator":
+                sib = sib.next_named_sibling
+            if sib is not None and sib.type == "method_definition":
+                mname = _ts_method_name(sib, source)
+                if mname:
+                    owner = _make_id(class_nid, mname)
+            emit(member, owner)
+        elif mt == "method_definition":
+            mname = _ts_method_name(member, source)
+            m_nid = _make_id(class_nid, mname) if mname else class_nid
+            for deco in _ts_descendant_decorators(member):
+                emit(deco, m_nid)
+        else:
+            # Fields / accessors: the member is not a node, so attribute its
+            # decorators (e.g. `@Input()`, `@Column()`) to the class.
+            for deco in _ts_descendant_decorators(member):
+                emit(deco, class_nid)
+
+
 def _ts_heritage_clause_entries(clause_node, source: bytes) -> list[str]:
     """Return base/interface type names from an extends_clause or implements_clause."""
     out: list[str] = []

tests/test_ts_decorators.py

@@ -0,0 +1,153 @@
+"""Regression tests: TypeScript/JavaScript decorator references.
+
+`@Component`, `@Injectable`, `@Input`, `@Inject`, `@Entity`, … emitted no edge
+to the decorator symbol — the `decorator` node kind was never walked. This is
+framework-critical (Angular, NestJS, Vue class components, TypeORM).
+
+Decorators are emitted as `references` edges with context="decorator" from the
+decorated entity: the class for class/field/parameter decorators, the method
+for method (and its parameter) decorators. Targets resolve through the same
+sourceless-stub path as type references, so a decorator imported from another
+module collapses onto its real definition.
+"""
+from pathlib import Path
+
+from graphify.extract import _file_stem, _make_id, extract
+
+
+def _write(path: Path, text: str) -> Path:
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text(text, encoding="utf-8")
+    return path
+
+
+def _class_nid(file: str, cls: str) -> str:
+    return _make_id(_file_stem(Path(file)), cls)
+
+
+def _method_nid(file: str, cls: str, method: str) -> str:
+    return _make_id(_class_nid(file, cls), method)
+
+
+def _has_deco(result: dict, owner_nid: str, deco: str) -> bool:
+    """True if owner_nid references the (cross-file, bare-stub) decorator symbol."""
+    tgt = _make_id(deco)
+    return any(
+        e["source"] == owner_nid
+        and e["target"] == tgt
+        and e["relation"] == "references"
+        and e.get("context") == "decorator"
+        for e in result["edges"]
+    )
+
+
+def test_class_decorator_on_exported_class(tmp_path):
+    # The canonical Angular shape: decorator sits on the wrapping export_statement.
+    f = _write(tmp_path / "src" / "c.ts",
+               "@Component({ selector: 'app' })\n"
+               "export class AppComponent {}\n")
+    r = extract([f], cache_root=tmp_path)
+    assert _has_deco(r, _class_nid("src/c.ts", "AppComponent"), "Component")
+
+
+def test_class_decorator_on_plain_class(tmp_path):
+    f = _write(tmp_path / "src" / "s.ts",
+               "@Injectable()\nclass Service {}\n")
+    r = extract([f], cache_root=tmp_path)
+    assert _has_deco(r, _class_nid("src/s.ts", "Service"), "Injectable")
+
+
+def test_stacked_class_decorators(tmp_path):
+    f = _write(tmp_path / "src" / "s.ts",
+               "@Injectable()\n@Entity()\nexport class Repo {}\n")
+    r = extract([f], cache_root=tmp_path)
+    nid = _class_nid("src/s.ts", "Repo")
+    assert _has_deco(r, nid, "Injectable")
+    assert _has_deco(r, nid, "Entity")
+
+
+def test_method_decorator_attributes_to_method(tmp_path):
+    f = _write(tmp_path / "src" / "c.ts",
+               "export class C {\n"
+               "  @HostListener('click') onClick() {}\n"
+               "}\n")
+    r = extract([f], cache_root=tmp_path)
+    assert _has_deco(r, _method_nid("src/c.ts", "C", "onClick"), "HostListener")
+    # and NOT to the class
+    assert not _has_deco(r, _class_nid("src/c.ts", "C"), "HostListener")
+
+
+def test_stacked_method_decorators(tmp_path):
+    f = _write(tmp_path / "src" / "c.ts",
+               "export class C {\n"
+               "  @Get('/') @UseGuards(Auth) list() {}\n"
+               "}\n")
+    r = extract([f], cache_root=tmp_path)
+    nid = _method_nid("src/c.ts", "C", "list")
+    assert _has_deco(r, nid, "Get")
+    assert _has_deco(r, nid, "UseGuards")
+
+
+def test_field_decorator_attributes_to_class(tmp_path):
+    # The field is not a graph node, so its decorator attributes to the class.
+    f = _write(tmp_path / "src" / "c.ts",
+               "export class C {\n"
+               "  @Input() name: string;\n"
+               "  @Column() age: number;\n"
+               "}\n")
+    r = extract([f], cache_root=tmp_path)
+    nid = _class_nid("src/c.ts", "C")
+    assert _has_deco(r, nid, "Input")
+    assert _has_deco(r, nid, "Column")
+
+
+def test_parameter_decorator_attributes_to_constructor(tmp_path):
+    f = _write(tmp_path / "src" / "c.ts",
+               "export class C {\n"
+               "  constructor(@Inject(TOKEN) private s: Svc) {}\n"
+               "}\n")
+    r = extract([f], cache_root=tmp_path)
+    assert _has_deco(r, _method_nid("src/c.ts", "C", "constructor"), "Inject")
+
+
+def test_namespaced_decorator_uses_property_name(tmp_path):
+    f = _write(tmp_path / "src" / "c.ts",
+               "@core.Component({})\nexport class Widget {}\n")
+    r = extract([f], cache_root=tmp_path)
+    assert _has_deco(r, _class_nid("src/c.ts", "Widget"), "Component")
+
+
+def test_external_decorator_stub_disambiguated_per_file(tmp_path):
+    """An external decorator (definition absent from the corpus — the common
+    framework case) still emits a `references`/`decorator` edge from every class
+    that applies it — the core behavior of this fix.
+
+    Convergence note (v0.9.0+): the edges no longer collapse onto a single shared
+    bare-name stub. v0.9.0 embeds the full repo-relative path in node IDs and
+    #1462 disambiguates imported type stubs across files, so the same external
+    `Injectable` referenced from two files now resolves to two distinct per-file
+    stubs (`src_a_ts_injectable`, `src_b_ts_injectable`) rather than one hub. (A
+    single in-corpus reference still keeps the bare `injectable` stub — only
+    cross-file, unresolved references are split.)"""
+    a = _write(tmp_path / "src" / "a.ts", "@Injectable()\nexport class A {}\n")
+    b = _write(tmp_path / "src" / "b.ts", "@Injectable()\nexport class B {}\n")
+    r = extract([a, b], cache_root=tmp_path)
+
+    # Each class emits exactly one decorator-context edge to an `Injectable`
+    # node (checked by label, since the stub id is now path-qualified).
+    id_to_label = {n["id"]: n.get("label") for n in r["nodes"]}
+    deco_edges = [
+        e for e in r["edges"]
+        if e["relation"] == "references" and e.get("context") == "decorator"
+    ]
+    a_targets = [e["target"] for e in deco_edges if e["source"] == _class_nid("src/a.ts", "A")]
+    b_targets = [e["target"] for e in deco_edges if e["source"] == _class_nid("src/b.ts", "B")]
+    assert len(a_targets) == 1 and id_to_label.get(a_targets[0]) == "Injectable"
+    assert len(b_targets) == 1 and id_to_label.get(b_targets[0]) == "Injectable"
+
+    # v0.9.0 full-path IDs + #1462 stub disambiguation: external stubs are split
+    # per file, so the two no longer converge on one shared hub.
+    assert a_targets[0] != b_targets[0], (
+        "external decorator stubs are disambiguated per file in v0.9.0+; "
+        "they no longer converge on a single shared stub"
+    )