fix: resolve tsconfig path aliases relative to baseUrl

_read_tsconfig_aliases joined alias targets onto the tsconfig's own
directory and ignored compilerOptions.baseUrl. In the common monorepo /
NestJS layout (baseUrl "./src" with "@services/*": ["services/*"]), the
alias resolved to <dir>/services instead of <dir>/src/services, so every
aliased import failed to resolve and the import edge was silently dropped
— leaving cross-file caller graphs nearly empty on alias-heavy TS repos.

Resolve `paths` relative to `baseUrl` (TypeScript's actual semantics),
defaulting to "." so configs without baseUrl keep their current behavior.
Add a regression test covering a subdirectory baseUrl; the existing alias
test only exercised baseUrl ".", which is why this slipped through.

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

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 Full release notes with details on each version: [GitHub Releases](https://github.com/safishamsi/graphify/releases)
 
+## Unreleased
+
+- Fix: tsconfig `paths` aliases are now resolved relative to `baseUrl`. `_read_tsconfig_aliases` previously joined alias targets onto the tsconfig's directory and ignored `compilerOptions.baseUrl`, so the common monorepo / NestJS layout (`baseUrl: "./src"` with `"@services/*": ["services/*"]`) resolved to `<dir>/services` instead of `<dir>/src/services` and every aliased import edge was silently dropped — leaving cross-file caller graphs nearly empty on alias-heavy TypeScript codebases. Resolution now joins `paths` onto `baseUrl` (defaulting to `.`, preserving prior behavior for configs without `baseUrl`).
+
 ## 0.8.37 (2026-06-10)
 
 - Security: SSRF guard rewritten to eliminate thread-safety race. The global `socket.getaddrinfo` monkey-patch is replaced with per-connection `_SSRFGuardedHTTPConnection`/`_SSRFGuardedHTTPSConnection` subclasses that resolve DNS once, validate the IP, and connect to that exact address — closing both the concurrent-thread race window and the underlying TOCTOU gap. No global state is mutated, so sibling threads (MCP server, PR triage pool) are unaffected.

graphify/extract.py

@@ -255,13 +255,23 @@ def _read_tsconfig_aliases(tsconfig: Path, base_dir: Path, seen: set) -> dict[st
         if extended_path.exists():
             aliases.update(_read_tsconfig_aliases(extended_path, extended_path.parent, seen))
 
-    paths = data.get("compilerOptions", {}).get("paths", {})
+    # tsconfig `paths` are resolved relative to `baseUrl` (itself relative to
+    # the tsconfig's directory), not the tsconfig directory directly. Honoring
+    # baseUrl is required for the common monorepo / NestJS layout where
+    # baseUrl points at a subdirectory, e.g. baseUrl "./src" with
+    # "@services/*": ["services/*"] must resolve to <dir>/src/services rather
+    # than <dir>/services. Defaults to "." so configs without baseUrl (paths
+    # relative to the tsconfig dir, the TS 4.1+ behavior) keep working.
+    compiler_options = data.get("compilerOptions", {})
+    base_url = compiler_options.get("baseUrl") or "."
+    paths_base = base_dir / base_url
+    paths = compiler_options.get("paths", {})
     for alias, targets in paths.items():
         if not targets:
             continue
         alias_prefix = alias.rstrip("/*")
         target_base = targets[0].rstrip("/*")
-        aliases[alias_prefix] = str(base_dir / target_base)
+        aliases[alias_prefix] = str(os.path.normpath(paths_base / target_base))
 
     return aliases
 

tests/test_js_import_resolution.py

@@ -334,6 +334,27 @@ def test_tsconfig_alias_import_resolves_existing_ts_file(tmp_path: Path):
     assert _has_edge(result, "src/routes/page.ts", "src/lib/types/type-helpers.ts")
 
 
+def test_tsconfig_alias_with_subdirectory_baseurl_resolves_existing_ts_file(tmp_path: Path):
+    # `paths` are resolved relative to `baseUrl`, which is commonly a
+    # subdirectory in monorepo / NestJS layouts (baseUrl "./src").
+    # Regression: baseUrl was ignored, so "@services/*": ["services/*"] with
+    # baseUrl "./src" resolved to <root>/services instead of <root>/src/services,
+    # and every aliased import edge was silently dropped.
+    _write(
+        tmp_path / "tsconfig.json",
+        json.dumps({"compilerOptions": {"baseUrl": "./src", "paths": {"@services/*": ["services/*"]}}}),
+    )
+    target = _write(tmp_path / "src/services/foo/index.ts", "export class Foo { id = '' }\n")
+    importer = _write(
+        tmp_path / "src/routes/page.ts",
+        "import { Foo } from '@services/foo'\nnew Foo()\n",
+    )
+
+    result = _extract_for([target, importer], tmp_path)
+
+    assert _has_edge(result, "src/routes/page.ts", "src/services/foo/index.ts")
+
+
 def test_tsconfig_array_extends_alias_resolves_existing_ts_file(tmp_path: Path):
     # TypeScript 5.0 allows `extends` as an array; later entries override
     # earlier ones. The `paths` alias is inherited from the second parent.