fix(python): a base list wrapped over several lines is read whole

CHANGELOG.md

@@ -30,6 +30,7 @@ and adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ### Fixes
 
+- In Python, a call through a module global holding a class whose base list is wrapped over several lines, as black and ruff write a long one, like `class Wrapped(\n    Mixin,\n    Base,\n):` then `current = Wrapped()` and `current.run()`, or through the class name, like `Wrapped.run(x)`, now reaches the method a base declares, as a one-line base list already did. Before, only the first line or three were read for this, so such a class seemed to have no bases. Re-index Python projects after upgrading.
 - In TypeScript, an awaited call with type arguments like `await fetchApi<User>("/me")` or `await api.get<T>(url)` now links to the function it calls. Before, the call was dropped, so typed fetch wrappers looked like they had no callers. (#2586)
 - In JavaScript and TypeScript, a call or `new` in a parameter's default value, like `function renderWithNote(note = buildNote())`, a destructured `{ size = defaultSize() }` or `constructor(private svc = new Service())`, now counts as the function's own call. Before, it was dropped, so `buildNote` was missing that caller and impact on it came back incomplete. Re-index JavaScript and TypeScript projects after upgrading. Thanks @inth3shadows for the report and the pull request. (#2588)
 - In React, a component rendered at module scope, in a top-level constant or inside a test's `it(…)` callback, like `createRoot(el).render(<App />)` or `render(<Card />)`, now counts as rendered there, so an app's entry reaches its root component and a component's tests show among its callers. (#2587)

__tests__/python-multiline-bases.test.ts

@@ -0,0 +1,182 @@
+/**
+ * A Python base list wrapped over several lines — as black and ruff write a
+ * long one, one base per line — is read whole by the resolver's own reader of
+ * a class's bases (`pythonBases`, behind module-global and `self.` dispatch).
+ * It read only the `class` line, so a module global holding such a class,
+ * `current = Wrapped()` then `current.run()`, reached no method its bases
+ * declare. Extraction already read the whole list.
+ */
+import { describe, it, expect, afterAll, beforeAll } from 'vitest';
+import * as fs from 'fs';
+import * as os from 'os';
+import * as path from 'path';
+import { CodeGraph } from '../src';
+
+let root = '';
+let cg: CodeGraph;
+
+beforeAll(async () => {
+  root = fs.mkdtempSync(path.join(os.tmpdir(), 'cg-py-multiline-bases-'));
+  fs.mkdirSync(path.join(root, 'app'));
+  fs.writeFileSync(path.join(root, 'app/__init__.py'), '');
+  fs.writeFileSync(path.join(root, 'app/m.py'), `from typing import Generic, TypeVar
+
+T = TypeVar("T")
+
+
+class Base(Generic[T]):
+    def run(self):
+        pass
+
+
+class Other:
+    def run(self):
+        pass
+
+
+class Mixin:
+    pass
+
+
+class OneLine(Mixin, Base):
+    pass
+
+
+class Wrapped(
+    Mixin,
+    Base,
+):
+    pass
+
+
+class Commented(
+    Mixin,  # no run here :)
+    # the base that declares run:
+    Base,
+):
+    pass
+
+
+class WrappedGeneric(
+    Mixin,
+    Base[
+        dict[str, int]
+    ],
+):
+    pass
+
+
+current_a = OneLine()
+current_b = Wrapped()
+current_c = Commented()
+current_d = WrappedGeneric()
+
+
+def use_one_line():
+    current_a.run()
+
+
+def use_wrapped():
+    current_b.run()
+
+
+def use_commented():
+    current_c.run()
+
+
+def use_wrapped_generic():
+    current_d.run()
+
+
+def keep(cls):
+    return cls
+
+
+@keep
+class DecoratedOneLine(Mixin, Base):
+    pass
+
+
+@keep
+class DecoratedWrapped(
+    Mixin,
+    Base,
+):
+    pass
+
+
+def class_one_line(x):
+    OneLine.run(x)
+
+
+def class_wrapped(x):
+    Wrapped.run(x)
+
+
+def class_commented(x):
+    Commented.run(x)
+
+
+def class_decorated_one_line(x):
+    DecoratedOneLine.run(x)
+
+
+def class_decorated_wrapped(x):
+    DecoratedWrapped.run(x)
+`);
+  cg = await CodeGraph.init(root, { index: true });
+});
+
+afterAll(() => {
+  cg?.close();
+  if (root) fs.rmSync(root, { recursive: true, force: true });
+});
+
+/** Qualified names of the methods `fn` calls. */
+const calls = (fn: string): string[] => {
+  const node = cg.getNodesInFile('app/m.py').find((n) => n.name === fn && n.kind === 'function')!;
+  expect(node, fn).toBeDefined();
+  return cg.getOutgoingEdges(node.id).filter((e) => e.kind === 'calls')
+    .map((e) => cg.getNode(e.target)!).filter((n) => n.kind === 'method').map((n) => n.qualifiedName);
+};
+
+describe('a Python base list wrapped over several lines', () => {
+  // Base and Other both declare `run`, and the globals are not named after
+  // their classes, so only the class's own bases can pick one.
+  it('resolves a module global through a one-line list (control)', () => {
+    expect(calls('use_one_line')).toEqual(['Base::run']);
+  });
+
+  it('resolves a module global through a wrapped list', () => {
+    expect(calls('use_wrapped')).toEqual(['Base::run']);
+  });
+
+  it('skips comments inside the list, parentheses and all', () => {
+    expect(calls('use_commented')).toEqual(['Base::run']);
+  });
+
+  it('reads a parameterized base wrapped inside the list', () => {
+    expect(calls('use_wrapped_generic')).toEqual(['Base::run']);
+  });
+});
+
+// A call through the class name, `Wrapped.run(x)`, finds `run` through the
+// supertypes the class head declares (`declaredSupertypes`), a second reader.
+describe('a class-name call through a wrapped base list', () => {
+  it('resolves through a one-line list (control)', () => {
+    expect(calls('class_one_line')).toEqual(['Base::run']);
+  });
+
+  it('resolves through a wrapped list', () => {
+    expect(calls('class_wrapped')).toEqual(['Base::run']);
+  });
+
+  it('skips comments inside the list, parentheses and all', () => {
+    expect(calls('class_commented')).toEqual(['Base::run']);
+  });
+
+  it('reads the head of a decorated class, one line or wrapped', () => {
+    expect(calls('class_decorated_one_line')).toEqual(['Base::run']);
+    expect(calls('class_decorated_wrapped')).toEqual(['Base::run']);
+  });
+});

src/resolution/name-matcher.ts

@@ -410,10 +410,31 @@ function pythonRefClass(name: string, ref: UnresolvedRef, context: ResolutionCon
   return classes.length === 1 ? classes[0]! : null;
 }
 
+/**
+ * A Python class's base list as written, up to its closing parenthesis, which
+ * may be lines below the `class` line: black and ruff wrap a long list one base
+ * per line. Comments in it are left out. Undefined for a class without one.
+ */
+function pythonBaseList(cls: Node, context: ResolutionContext): string | undefined {
+  const lines = context.getFileLines?.(cls.filePath) ?? context.readFile(cls.filePath)?.split('\n') ?? [];
+  const head = /^\s*class\s+\w+\s*\(/.exec(lines[cls.startLine - 1] ?? '');
+  if (!head) return undefined;
+  let list = '';
+  let depth = 1;
+  for (let i = cls.startLine - 1; i < Math.max(cls.endLine, cls.startLine); i++) {
+    const text = (i === cls.startLine - 1 ? lines[i]!.slice(head[0].length) : lines[i] ?? '').replace(/#.*$/, '');
+    for (const ch of text) {
+      if (ch === '(') depth++;
+      else if (ch === ')' && --depth === 0) return list;
+      list += ch;
+    }
+    list += ' ';
+  }
+  return undefined;
+}
+
 function pythonBases(cls: Node, ref: UnresolvedRef, context: ResolutionContext): Node[] {
-  const line = context.getFileLines?.(cls.filePath)?.[cls.startLine - 1]
-    ?? context.readFile(cls.filePath)?.split('\n')[cls.startLine - 1] ?? '';
-  let bases = line.match(/^\s*class\s+\w+\s*\(([^)]*)\)/)?.[1];
+  let bases = pythonBaseList(cls, context);
   // A parameterized base, `Base[str]` or `Pair[str, Dict[str, int]]`, names its class before the brackets.
   while (bases && /\[[^[\]]*\]/.test(bases)) bases = bases.replace(/\[[^[\]]*\]/g, '');
   return (bases?.split(',') ?? []).flatMap(name => {
@@ -21517,8 +21538,10 @@ function readDeclaredSupertypes(cls: Node, context: ResolutionContext): string[]
     // BaseManager.from_queryset(QuerySet))` — subclasses that class: the
     // qualifier is the supertype, not the method called on it.
     // A parameterized base, `Base[User]`, is `Base`: its type arguments are no supertypes.
+    // The list is read whole, as `pythonBases` reads it: black and ruff wrap a
+    // long one past the three lines `head` holds.
     case 'python': {
-      let bases = /\bclass\s+\w+\s*\(([^)]*)\)/.exec(head)?.[1];
+      let bases = pythonBaseList(cls, context);
       while (bases && /\[[^[\]]*\]/.test(bases)) bases = bases.replace(/\[[^[\]]*\]/g, '');
       return names(bases?.replace(/\w+\s*=\s*[\w.]+/g, '').replace(/([A-Za-z_][\w.]*)\.\w+\s*\(/g, '$1 ('));
     }