fix(cli): normalize full-scan fast previews

Author: awsl233777

cli.js

@@ -4789,7 +4789,14 @@ function extractSessionDetailPreviewFromFileFast(filePath, source, messageLimit)
 
         if (position > 0) {
             latest.clipped = latest.clipped || position > 0;
-        }
+            return latest;
+        }
+        const normalizedMessages = removeLeadingSystemMessage(latest.messages);
+        latest.messages = normalizedMessages.length > safeMessageLimit
+            ? normalizedMessages.slice(-safeMessageLimit)
+            : normalizedMessages;
+        latest.totalMessages = normalizedMessages.length;
+        latest.clipped = latest.totalMessages > latest.messages.length;
         return latest;
     } catch (_) {
         return null;

tests/unit/session-detail-preview-fast.test.mjs

@@ -85,6 +85,22 @@ test('extractSessionDetailPreviewFromFileFast preserves clipped previews after f
                     return content;
                 }
                 return '';
+            },
+            removeLeadingSystemMessage(messages) {
+                if (!Array.isArray(messages)) {
+                    return [];
+                }
+                let startIndex = 0;
+                while (startIndex < messages.length) {
+                    const item = messages[startIndex];
+                    const role = item && typeof item.role === 'string' ? item.role : '';
+                    if (role === 'system') {
+                        startIndex += 1;
+                        continue;
+                    }
+                    break;
+                }
+                return startIndex > 0 ? messages.slice(startIndex) : messages;
             }
         });
 
@@ -98,3 +114,97 @@ test('extractSessionDetailPreviewFromFileFast preserves clipped previews after f
         fs.rmSync(tmpDir, { recursive: true, force: true });
     }
 });
+
+test('extractSessionDetailPreviewFromFileFast normalizes full-scan previews before returning', () => {
+    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'codexmate-fast-preview-full-'));
+    const filePath = path.join(tmpDir, 'session.jsonl');
+
+    try {
+        const records = [
+            {
+                type: 'response_item',
+                payload: {
+                    type: 'message',
+                    role: 'system',
+                    content: 'bootstrap'
+                },
+                timestamp: '2025-04-12T00:00:00.000Z'
+            },
+            {
+                type: 'response_item',
+                payload: {
+                    type: 'message',
+                    role: 'user',
+                    content: 'hello'
+                },
+                timestamp: '2025-04-12T00:00:01.000Z'
+            },
+            {
+                type: 'response_item',
+                payload: {
+                    type: 'message',
+                    role: 'assistant',
+                    content: 'world'
+                },
+                timestamp: '2025-04-12T00:00:02.000Z'
+            }
+        ];
+        fs.writeFileSync(filePath, records.map((record) => JSON.stringify(record)).join('\n') + '\n', 'utf-8');
+
+        const extractSessionDetailPreviewFromFileFast = instantiateExtractSessionDetailPreviewFromFileFast({
+            fs,
+            getFileStatSafe(targetPath) {
+                try {
+                    return fs.statSync(targetPath);
+                } catch (_) {
+                    return null;
+                }
+            },
+            FAST_SESSION_DETAIL_PREVIEW_FILE_BYTES: 32,
+            FAST_SESSION_DETAIL_PREVIEW_MAX_BYTES: 4096,
+            FAST_SESSION_DETAIL_PREVIEW_CHUNK_BYTES: 256,
+            DEFAULT_SESSION_DETAIL_MESSAGES: 300,
+            toIsoTime(value, fallback = '') {
+                return typeof value === 'string' && value ? value : fallback;
+            },
+            normalizeRole(role) {
+                const normalized = String(role || '').trim().toLowerCase();
+                return normalized === 'user' || normalized === 'assistant' || normalized === 'system'
+                    ? normalized
+                    : '';
+            },
+            extractMessageText(content) {
+                return typeof content === 'string' ? content : '';
+            },
+            removeLeadingSystemMessage(messages) {
+                if (!Array.isArray(messages)) {
+                    return [];
+                }
+                let startIndex = 0;
+                while (startIndex < messages.length) {
+                    const item = messages[startIndex];
+                    const role = item && typeof item.role === 'string' ? item.role : '';
+                    if (role === 'system') {
+                        startIndex += 1;
+                        continue;
+                    }
+                    break;
+                }
+                return startIndex > 0 ? messages.slice(startIndex) : messages;
+            }
+        });
+
+        const preview = extractSessionDetailPreviewFromFileFast(filePath, 'codex', 5);
+
+        assert(preview, 'full-scan fast preview should still return a preview');
+        assert.deepStrictEqual(
+            preview.messages.map((item) => item.role),
+            ['user', 'assistant'],
+            'full-scan previews should strip leading system/bootstrap messages'
+        );
+        assert.strictEqual(preview.totalMessages, 2, 'full-scan previews should restore an exact total');
+        assert.strictEqual(preview.clipped, false, 'full-scan previews should not stay clipped when all messages fit');
+    } finally {
+        fs.rmSync(tmpDir, { recursive: true, force: true });
+    }
+});