fix(audit): expand tilde paths for audit log output

src/audit/logger.test.ts

@@ -0,0 +1,49 @@
+import { existsSync, mkdtempSync, readFileSync, rmSync } from 'fs';
+import { homedir, tmpdir } from 'os';
+import { join, resolve } from 'path';
+import { describe, expect, it } from 'vitest';
+import { AuditLogger } from './logger.js';
+
+describe('AuditLogger', () => {
+  it('expands ~ in audit path before writing logs', async () => {
+    const previousHome = process.env.HOME;
+    const tempHome = mkdtempSync(join(tmpdir(), 'flynn-audit-home-'));
+    process.env.HOME = tempHome;
+
+    try {
+      // Sanity-check this process sees the temp home.
+      expect(homedir()).toBe(tempHome);
+
+      const logger = new AuditLogger({
+        enabled: true,
+        path: '~/.local/share/flynn/audit.log',
+        max_size_mb: 10,
+        keep_days: 30,
+        levels: {
+          tools: 'debug',
+          sessions: 'debug',
+          automation: 'debug',
+        },
+      });
+
+      logger.systemStart('test-component');
+      await logger.close();
+      await new Promise((resolvePromise) => setTimeout(resolvePromise, 25));
+
+      const loggerPath = (logger as unknown as { config: { path: string } }).config.path;
+      const expectedPath = resolve(tempHome, '.local/share/flynn/audit.log');
+      expect(loggerPath).toBe(expectedPath);
+      expect(existsSync(expectedPath)).toBe(true);
+      const content = readFileSync(expectedPath, 'utf-8');
+      expect(content).toContain('"event_type":"system.start"');
+      expect(content).toContain('"component":"test-component"');
+    } finally {
+      if (previousHome === undefined) {
+        delete process.env.HOME;
+      } else {
+        process.env.HOME = previousHome;
+      }
+      rmSync(tempHome, { recursive: true, force: true });
+    }
+  });
+});

src/audit/logger.ts

@@ -1,5 +1,6 @@
 import { createWriteStream, existsSync, mkdirSync } from 'fs';
-import { dirname } from 'path';
+import { dirname, resolve } from 'path';
+import { homedir } from 'os';
 import type {
   AuditEvent,
   AuditConfig,
@@ -41,8 +42,11 @@ export class AuditLogger {
   private rotator: AuditRotator;
 
   constructor(config: AuditConfig) {
-    this.config = config;
-    this.rotator = new AuditRotator(config);
+    this.config = {
+      ...config,
+      path: expandPath(config.path),
+    };
+    this.rotator = new AuditRotator(this.config);
 
     if (!this.config.enabled) {
       return;
@@ -50,7 +54,7 @@ export class AuditLogger {
 
     this.ensureLogDirectory();
     this.rotator.checkRotation();
-    this.writeStream = createWriteStream(config.path, { flags: 'a' });
+    this.writeStream = createWriteStream(this.config.path, { flags: 'a' });
   }
 
   private ensureLogDirectory(): void {
@@ -357,3 +361,10 @@ export class AuditLogger {
     }
   }
 }
+
+function expandPath(p: string): string {
+  if (p.startsWith('~/') || p === '~') {
+    return resolve(homedir(), p.slice(2));
+  }
+  return resolve(p);
+}