Fix usage scanner fixture false positives

src/usage/scanner.ts

@@ -1,10 +1,20 @@
 import fs from "node:fs";
 import path from "node:path";
-// Shared with lockfile scanning in utils/file.ts; additions affect both code paths.
 import { EXCLUDED_DIRS } from "../constants.js";
 
 const ALLOWED_EXTS = new Set([".js", ".jsx", ".ts", ".tsx", ".mjs", ".cjs"]);
 const MAX_FILES_TO_SCAN = 5000;
+const ALL_IMPORTS_EXCLUDED_DIRS = new Set([
+  ...EXCLUDED_DIRS,
+  "__fixtures__",
+  "__tests__",
+  "example",
+  "examples",
+  "fixture",
+  "fixtures",
+  "test",
+  "tests",
+]);
 
 // Matches:
 // import { foo } from 'pkg'
@@ -130,7 +140,7 @@ export function scanAllImports(projectPath: string): Map<string, string[]> {
       if (scannedCount >= MAX_FILES_TO_SCAN) return;
       const fullPath = path.join(dir, entry.name);
       if (entry.isDirectory()) {
-        if (!EXCLUDED_DIRS.has(entry.name) && !entry.name.startsWith(".")) {
+        if (!ALL_IMPORTS_EXCLUDED_DIRS.has(entry.name) && !entry.name.startsWith(".")) {
           walk(fullPath);
         }
       } else if (entry.isFile()) {

tests/overrides/context-builder.test.ts

@@ -1,4 +1,4 @@
-import { mkdtempSync, writeFileSync, rmSync } from "node:fs";
+import { mkdirSync, mkdtempSync, writeFileSync, rmSync } from "node:fs";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { buildOverrideContext } from "../../src/overrides/context-builder.js";
@@ -42,6 +42,37 @@ describe("buildOverrideContext", () => {
     expect(ctx.lockfilePackageNames.has("postcss")).toBe(true);
   });
 
+  it("does not count imports from example, test, or fixture directories", () => {
+    writeFileSync(join(dir, "package.json"), JSON.stringify({
+      name: "x",
+      overrides: { "js-yaml": "^4.1.0" },
+    }));
+    writeFileSync(join(dir, "package-lock.json"), JSON.stringify({
+      lockfileVersion: 3,
+      packages: {
+        "": { name: "x" },
+        "node_modules/js-yaml": { version: "4.1.0" },
+      },
+    }));
+    mkdirSync(join(dir, "examples", "demo", "src"), { recursive: true });
+    mkdirSync(join(dir, "tests"), { recursive: true });
+    mkdirSync(join(dir, "fixtures", "project", "src"), { recursive: true });
+    mkdirSync(join(dir, "src"), { recursive: true });
+    writeFileSync(join(dir, "examples", "demo", "src", "index.ts"), "import yaml from 'js-yaml';");
+    writeFileSync(join(dir, "tests", "usage.test.ts"), "const fixture = `import yaml from 'js-yaml';`;");
+    writeFileSync(join(dir, "fixtures", "project", "src", "index.ts"), "require('js-yaml');");
+    writeFileSync(join(dir, "src", "index.ts"), "import { parse } from 'semver';");
+
+    const ctx = buildOverrideContext(dir, {
+      auditLog: NULL_AUDIT_LOG,
+      logger: makeNoopLogger() as any,
+      checkNetwork: false,
+    });
+
+    expect(ctx.importedPackageNames.has("js-yaml")).toBe(false);
+    expect(ctx.importedPackageNames.get("semver")).toEqual([expect.stringMatching(/src.index\.ts/)]);
+  });
+
   it("flags OA001/OA004/OA006/OA008 as skipped when node_modules is absent", () => {
     writeFileSync(join(dir, "package.json"), JSON.stringify({
       name: "x",

tests/usage.test.ts

@@ -70,6 +70,23 @@ describe("scanProjectForPackageUsage", () => {
     expect(results["lodash"][0]).toMatch(/src.index\.js/);
   });
 
+  it("keeps example, test, and fixture imports for usage filtering", () => {
+    createTestFile("examples/demo/src/index.ts", "import yaml from 'js-yaml';");
+    createTestFile("tests/usage.test.ts", "const fixture = `import yaml from 'js-yaml';`;");
+    createTestFile("fixtures/project/src/index.ts", "require('js-yaml');");
+    createTestFile("src/index.ts", "import yaml from 'js-yaml';");
+
+    const results = scanProjectForPackageUsage(tempDir, new Set(["js-yaml"]));
+
+    expect(results["js-yaml"]).toHaveLength(4);
+    expect(results["js-yaml"]).toEqual(expect.arrayContaining([
+      expect.stringMatching(/examples.demo.src.index\.ts/),
+      expect.stringMatching(/tests.usage\.test\.ts/),
+      expect.stringMatching(/fixtures.project.src.index\.ts/),
+      expect.stringMatching(/src.index\.ts/),
+    ]));
+  });
+
   it("should extract bare module names correctly", () => {
     createTestFile("src/index.js", `
       import { x } from 'lodash/fp/map';
@@ -146,4 +163,16 @@ describe("scanAllImports", () => {
     const result = scanAllImports(tempDir);
     expect(result.has("bar")).toBe(false);
   });
+
+  it("excludes example, test, and fixture imports", () => {
+    createFile("examples/pd001-override-phantom/src/index.ts", `import yaml from 'js-yaml';`);
+    createFile("tests/usage.test.ts", `const fixture = \`import yaml from 'js-yaml';\`;`);
+    createFile("fixtures/project/src/index.ts", `require('js-yaml');`);
+    createFile("src/index.ts", `import { parse } from 'semver';`);
+
+    const result = scanAllImports(tempDir);
+
+    expect(result.has("js-yaml")).toBe(false);
+    expect(result.get("semver")).toEqual([expect.stringMatching(/src.index\.ts/)]);
+  });
 });