fix(kernel): mirror interface members (#1638) on the Rust path, and fix the member signature on both

codegraph-kernel/src/tsjs/extractors.rs

@@ -270,8 +270,33 @@ impl<'t> Walker<'t> {
         let name = self.text(name_node).to_string();
 
         // TS/JS field definitions carry an explicit `type` field; the generic
-        // scan is for other languages (#808).
-        let type_text = node.child_by_field_name("type").map(|t| {
+        // scan is for other languages (#808). A `property_signature` (an
+        // interface member, #1638) carries a `type` field and no value, so it
+        // reads the type field too: the generic scan's exclusion list covers
+        // `identifier` but not the `property_identifier` an interface member is
+        // named with, so it would stop on the name and make the signature repeat
+        // it (`counts counts`) instead of naming the type. Mirrors
+        // extractProperty's isTsJsField.
+        let is_ts_js_field = matches!(
+            node.kind(),
+            "public_field_definition" | "field_definition" | "property_signature"
+        );
+        let type_node = if is_ts_js_field {
+            node.child_by_field_name("type")
+        } else {
+            (0..node.named_child_count()).filter_map(|i| node.named_child(i)).find(|c| {
+                !matches!(
+                    c.kind(),
+                    "modifier"
+                        | "modifiers"
+                        | "identifier"
+                        | "accessor_list"
+                        | "accessors"
+                        | "equals_value_clause"
+                )
+            })
+        };
+        let type_text = type_node.map(|t| {
             let raw = self.text(t);
             raw.strip_prefix(':').unwrap_or(raw).trim_start().to_string()
         });

codegraph-kernel/src/tsjs/mod.rs

@@ -55,10 +55,32 @@ impl Variant {
 /// typescriptExtractor.methodTypes / javascriptExtractor.methodTypes.
 fn is_method_type(v: Variant, kind: &str) -> bool {
     kind == "method_definition"
-        || (v.is_ts() && kind == "public_field_definition")
+        || (v.is_ts() && matches!(kind, "public_field_definition" | "method_signature"))
         || (!v.is_ts() && kind == "field_definition")
 }
 
+/// typescriptExtractor.propertyTypes. The interface counterpart of
+/// `public_field_definition`: it carries no value, so it is always a property
+/// and never goes through classify_ts_class_member (#1638).
+fn is_property_type(v: Variant, kind: &str) -> bool {
+    v.is_ts() && kind == "property_signature"
+}
+
+/// Method node types that spell a SIGNATURE — a declaration with no body (#1638).
+///
+/// They are a method of whatever type declares them and nothing on their own, so
+/// they must not take `extract_method`'s "no class-like parent, so treat it as a
+/// free function" fallback. The other method types can: a `method_definition`
+/// outside a class really is a function. This one appears outside a class only
+/// inside a type literal (`type Handle = { stop(): void }`), whose members
+/// `extract_ts_type_alias_members` already extracts and attaches to the alias
+/// (#359) — take the fallback and the file gains a phantom top-level
+/// `function stop` beside the real `Handle::stop`. Mirrors the TS extractor's
+/// SIGNATURE_METHOD_NODE_TYPES (extraction/tree-sitter.ts).
+fn is_signature_method_type(kind: &str) -> bool {
+    kind == "method_signature"
+}
+
 fn is_function_type(kind: &str) -> bool {
     matches!(kind, "function_declaration" | "arrow_function" | "function_expression")
 }
@@ -622,7 +644,9 @@ impl<'t> Walker<'t> {
         } else if is_class_type(self.variant, kind) {
             self.extract_class(node);
             skip_children = true;
-        } else if is_method_type(self.variant, kind) {
+        } else if is_method_type(self.variant, kind)
+            && (!is_signature_method_type(kind) || self.inside_class_like())
+        {
             if classify_ts_class_member(node) == Member::Property {
                 let prop = self.extract_property(node);
                 if let (Some((row, name)), Some(value)) = (prop, node.child_by_field_name("value")) {
@@ -664,12 +688,22 @@ impl<'t> Walker<'t> {
             self.extract_call(node);
         } else if kind == "new_expression" {
             self.extract_instantiation(node);
-        } else if self.variant.is_ts()
-            && matches!(kind, "property_signature" | "method_signature")
-            && self.inside_class_like()
-        {
-            let parent = self.top_row();
-            self.extract_type_annotations(node, parent);
+        } else if is_property_type(self.variant, kind) && self.inside_class_like() {
+            // NOTE: `property_signature` / `method_signature` used to be handled
+            // here together, hanging their type annotations off the ENCLOSING
+            // INTERFACE — the only anchor available while the members themselves
+            // went unextracted. Since #1638 `method_signature` is a method type
+            // and `property_signature` a property type, so the method branch
+            // above claims the first (under the same inside_class_like guard
+            // this branch had) and this one extracts the second as a real node.
+            // The `references` edges survive — extract_method and
+            // extract_property each call extract_type_annotations — but now hang
+            // off the member, the more precise anchor: `Api::fetch → PageId`
+            // says which member wants the type, where `Api → PageId` only said
+            // the file did.
+            self.extract_property(node);
+            self.scan_fn_ref_subtree(node, 0);
+            skip_children = true;
         }
 
         if !skip_children {

src/extraction/tree-sitter.ts

@@ -2049,8 +2049,18 @@ export class TreeSitterExtractor {
     // and the initializer VALUE, which the generic finder below would
     // wrongly pick — so fields use the type field only (#808). Other
     // languages (C# property_declaration) keep the generic scan.
+    //
+    // A `property_signature` (an interface member, #1638) carries a `type`
+    // field and no value, so it reads the type field too. It cannot take the
+    // generic scan: that scan's exclusion list covers `identifier` but not the
+    // `property_identifier` an interface member is named with, so it stops on
+    // the name and `interface Stats { counts: Record<string, number> }` yields
+    // `signature: "counts counts"` instead of the type. Named explicitly
+    // rather than folded into the field test so no other language's
+    // `property_declaration` moves off the generic scan.
     const isTsJsField =
-      node.type === 'public_field_definition' || node.type === 'field_definition';
+      node.type === 'public_field_definition' || node.type === 'field_definition'
+      || node.type === 'property_signature';
     const typeNode = isTsJsField
       ? getChildByField(node, 'type')
       : node.namedChildren.find(