TypeScript: interface members are never indexed (method_signature/property_signature missing from the extractor) — every call through a .d.ts platform API is invisible #1638

Summary

The TypeScript extractor never indexes interface members. interface_declaration is captured, but the method_signature and property_signature nodes inside it are not, so an interface's methods and properties do not exist in the graph.

The consequence is larger than it first looks: for any codebase whose platform/SDK API is expressed as interface method signatures in a .d.ts (very common — a vendored platform SDK, a generated client, @types/*), every call site through that API is invisible, because there is no declaration node for the call edge to attach to.

Java and C# are unaffected: in those grammars interface methods reuse method_declaration, which is already in their methodTypes. TypeScript is uniquely affected because tree-sitter-typescript uses distinct method_signature / property_signature node types.

Repro

api.d.ts, the whole project:

export interface PlatformContext {
  deleteQueueCustomAck(queueName: string, thingId: number): void
  createQueueCustomAckKey(queueName: string, thingId: number): void
  readonly tenantId: string
}

$ codegraph init
● 2 nodes, 1 edges

Nodes by Kind:
  file            1
  interface       1

$ codegraph node PlatformContext
**PlatformContext** (interface)          ← found

$ codegraph node deleteQueueCustomAck
Symbol "deleteQueueCustomAck" not found in the codebase

$ codegraph node tenantId
Symbol "tenantId" not found in the codebase

Zero method and zero property nodes for an interface that declares two methods and a property.

Note the members are found if a class implements them — the class's method_definition nodes are picked up — which is why this is easy to miss. An interface-only declaration file (.d.ts) exposes it cleanly.

Root cause

src/extraction/languages/typescript.ts:

methodTypes: ['method_definition', 'public_field_definition'],
interfaceTypes: ['interface_declaration'],
// no propertyTypes

Neither method_signature nor property_signature appears anywhere in the file (still true on main as of today).

The traversal side is already correct — isInsideClassLikeNode() in src/extraction/tree-sitter.ts already lists 'interface':

return (parentNode.kind === 'class' ||
        parentNode.kind === 'struct' ||
        parentNode.kind === 'interface' ||   // already handled
        ...);

So the walker will attach members to an interface parent as soon as the node types are declared. This looks like a config omission rather than a design decision.

Suggested fix

methodTypes: ['method_definition', 'public_field_definition', 'method_signature'],
propertyTypes: ['property_signature'],

Verified effect

Applied to a local v1.4.1 install:

Re-index cost was unchanged in practice (47s for the monorepo).

Related but distinct

• resolution: an imports edge lands on a class property or interface method that merely shares the imported name (import path from 'node:path' → SomeType::path) #1537 — an imports edge landing on an interface method that shares a name. That one implies interface methods are expected to be addressable; this issue is why they are not, in TS.
• TS/JS class fields with type annotations are extracted as method-kind nodes #808 (closed) — TS/JS class fields extracted as method-kind nodes. Same file, different node types.

Secondary note (not part of this issue)

For the .d.ts-in-node_modules case specifically, the patch alone is not enough, because node_modules is a hard-coded ignore that neither codegraph.json include nor includeIgnored overrides. Indexing the package as its own project works as a workaround. Mentioning only because it is the most common place platform interfaces live; happy to open that separately if it is worth its own discussion.

Environment

• CodeGraph 1.4.1 (behaviour confirmed unchanged on main)
• macOS, TypeScript sources