eslint.config.js

@@ -59,6 +59,11 @@ export default [
       boundaries,
     },
     settings: {
+      "import/resolver": {
+        node: {
+          extensions: [".ts", ".tsx", ".js", ".jsx"],
+        },
+      },
       "boundaries/elements": [
         { type: "routes", pattern: "src/routes/*" },
         { type: "mf", pattern: "src/mf/*" },
@@ -107,10 +112,13 @@ export default [
     },
   },
   // --- Restricted imports (master plan §1A-3) ---
-  // OTel SDK internals: only src/observability/metrics/otel.ts may import them
+  // OTel SDK internals + react-i18next: merged into one block so ESLint 9
+  // flat config doesn't override one rule with the other.
+  // otel.ts is allowed to import OTel SDK; provider.tsx is allowed to import react-i18next.
+  // Neither file needs the other's exemption, so combining ignores is safe.
   {
     files: ["src/**/*.{ts,tsx}"],
-    ignores: ["src/observability/metrics/otel.ts"],
+    ignores: ["src/observability/metrics/otel.ts", "src/i18n/provider.tsx"],
     rules: {
       "no-restricted-imports": [
         "error",
@@ -124,20 +132,6 @@ export default [
               name: "@opentelemetry/sdk-node",
               message: "Import from @opentelemetry/api or use getMeter()/getTracer() from @/observability/metrics/otel instead. Direct SDK access is restricted to src/observability/metrics/otel.ts.",
             },
-          ],
-        },
-      ],
-    },
-  },
-  // react-i18next: only src/i18n/provider.tsx may import it
-  {
-    files: ["src/**/*.{ts,tsx}"],
-    ignores: ["src/i18n/provider.tsx"],
-    rules: {
-      "no-restricted-imports": [
-        "error",
-        {
-          paths: [
             {
               name: "react-i18next",
               message: "Import useTranslation from @/i18n/provider instead. Direct react-i18next imports are restricted to src/i18n/provider.tsx.",

tests/eslint/boundaries.test.ts

@@ -0,0 +1,130 @@
+import { describe, expect, it } from "vitest";
+import { execSync } from "node:child_process";
+import fs from "node:fs";
+import path from "node:path";
+import crypto from "node:crypto";
+
+const ROOT = path.resolve(import.meta.dirname, "../..");
+
+/** Short random suffix to avoid collisions when tests run in parallel. */
+function uid(): string {
+  return crypto.randomBytes(4).toString("hex");
+}
+
+/**
+ * Removes a file and any empty parent directories up to (but not including) the src/ tree root.
+ */
+function cleanupProbe(absPath: string): void {
+  try {
+    fs.unlinkSync(absPath);
+  } catch {
+    /* file may not exist */
+  }
+  let dir = path.dirname(absPath);
+  const srcDir = path.join(ROOT, "src");
+  while (dir.length > srcDir.length) {
+    try {
+      fs.rmdirSync(dir);
+    } catch {
+      break;
+    }
+    dir = path.dirname(dir);
+  }
+}
+
+/**
+ * Creates a probe source file, optionally a target file, runs ESLint, and cleans up.
+ */
+function lintProbe(
+  sourcePath: string,
+  sourceContent: string,
+  targetPath?: string,
+  targetContent?: string,
+): string {
+  const absSrc = path.join(ROOT, sourcePath);
+  const absTarget = targetPath ? path.join(ROOT, targetPath) : null;
+  fs.mkdirSync(path.dirname(absSrc), { recursive: true });
+  fs.writeFileSync(absSrc, sourceContent, "utf8");
+  if (absTarget && targetContent) {
+    fs.mkdirSync(path.dirname(absTarget), { recursive: true });
+    fs.writeFileSync(absTarget, targetContent, "utf8");
+  }
+  try {
+    execSync(`pnpm exec eslint "${absSrc}" --format json`, {
+      cwd: ROOT,
+      encoding: "utf8",
+      stdio: ["pipe", "pipe", "pipe"],
+    });
+    return "PASS";
+  } catch (err: unknown) {
+    const error = err as { stdout?: string };
+    return error.stdout ?? "UNKNOWN_ERROR";
+  } finally {
+    cleanupProbe(absSrc);
+    if (absTarget) {
+      cleanupProbe(absTarget);
+    }
+  }
+}
+
+const TARGET_CONTENT = "export const something = 1;\n";
+
+describe("boundaries rules", () => {
+  it("features/ cannot import from routes/", () => {
+    const id = uid();
+    const result = lintProbe(
+      `src/features/online-board/__bnd_probe_${id}__.ts`,
+      `import { something } from "../../routes/__probe_${id}__/__target_probe__";\nexport const x = something;\n`,
+      `src/routes/__probe_${id}__/__target_probe__.ts`,
+      TARGET_CONTENT,
+    );
+    expect(result).toContain("boundaries/element-types");
+  });
+
+  it("features/ cannot import from mf/", () => {
+    const id = uid();
+    const result = lintProbe(
+      `src/features/online-board/__bnd_probe_${id}__.ts`,
+      `import { something } from "../../mf/expose/__target_probe_${id}__";\nexport const x = something;\n`,
+      `src/mf/expose/__target_probe_${id}__.ts`,
+      TARGET_CONTENT,
+    );
+    expect(result).toContain("boundaries/element-types");
+  });
+
+  it("ui/ cannot import from features/", () => {
+    const id = uid();
+    const result = lintProbe(
+      `src/ui/__probe_${id}__/__bnd_probe__.ts`,
+      'import { something } from "../../features/online-board/index";\nexport const x = something;\n',
+    );
+    expect(result).toContain("boundaries/element-types");
+  });
+
+  it("shared/ cannot import from features/", () => {
+    const id = uid();
+    const result = lintProbe(
+      `src/shared/__probe_${id}__/__bnd_probe__.ts`,
+      'import { something } from "../../features/online-board/index";\nexport const x = something;\n',
+    );
+    expect(result).toContain("boundaries/element-types");
+  });
+
+  it("observability/ cannot import from features/", () => {
+    const id = uid();
+    const result = lintProbe(
+      `src/observability/logger/__bnd_probe_${id}__.ts`,
+      'import { something } from "../../features/online-board/index";\nexport const x = something;\n',
+    );
+    expect(result).toContain("boundaries/element-types");
+  });
+
+  it("features/ CAN import from env/ (allowed direction)", () => {
+    const id = uid();
+    const result = lintProbe(
+      `src/features/online-board/__bnd_probe_${id}__.ts`,
+      'import { getEnv } from "../../env/index";\nexport const x = getEnv;\n',
+    );
+    expect(result).not.toContain("boundaries/element-types");
+  });
+});

vitest.config.ts

@@ -12,7 +12,7 @@ export default defineConfig({
     environment: "node",
     globals: true,
     passWithNoTests: true,
-    include: ["src/**/*.test.ts", "src/**/*.test.tsx"],
+    include: ["src/**/*.test.ts", "src/**/*.test.tsx", "tests/**/*.test.ts"],
     coverage: {
       provider: "v8",
       reporter: ["text", "json-summary", "lcov"],