feat: trim creates new session "...(trim)" instead of overwriting (v0.8.7)

- Trim no longer touches the original session file at all
- Creates a new .jsonl with fresh UUID alongside the original
- New session's customTitle = original title + " (trim)"
- All UUIDs/parentUUIDs remapped to keep linked-list chain valid
- Both sessions visible in the tree after refresh

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Myoontyee

package.json

@@ -2,7 +2,7 @@
   "name": "claude-code-exporter",
   "displayName": "Claude Code Exporter — Claude Code, Codex & Cursor Conversation History",
   "description": "Export AI coding agent conversations to Markdown. Supports Claude Code (→ .claude-code-history/), OpenAI Codex (→ .codex-history/), and Cursor Composer (→ .cursor-history/). Features: auto-watch, session inject/import for claude --resume, and repair of thinking-block signature errors when switching API providers.",
-  "version": "0.8.6",
+  "version": "0.8.7",
   "publisher": "myoontyee",
   "engines": {
     "vscode": "^1.85.0"

src/extension.ts

@@ -540,8 +540,8 @@ export function activate(context: vscode.ExtensionContext): void {
         try {
           const r = trimSession(picked.value, Number(keepInput));
           vscode.window.showInformationMessage(
-            `✓ 裁剪完成 / Trimmed: ${r.originalLines} → ${r.keptLines} 行  (${r.sizeMb.toFixed(1)} MB → ${r.trimmedSizeMb.toFixed(1)} MB)\n\n` +
-            `备份位置 / Backup: ${r.backupPath}\n\n关闭并重新打开 CC 对话面板以生效 / Close and reopen CC chat to reload.`,
+            `✓ 裁剪副本已创建 / Trim copy created: ${r.originalLines} → ${r.keptLines} 行  (${r.sizeMb.toFixed(1)} MB → ${r.trimmedSizeMb.toFixed(1)} MB)\n\n` +
+            `原对话不变，裁剪版标题为 "...(trim)"，刷新列表即可看到 / Original unchanged. Trimmed copy titled "...(trim)" — refresh to see it.`,
             { modal: true }
           );
         } catch (err) {
@@ -611,8 +611,8 @@ export function activate(context: vscode.ExtensionContext): void {
       try {
         const r = trimSession(jsonlPath, Number(keepInput));
         vscode.window.showInformationMessage(
-          `✓ 裁剪完成 / Trimmed: ${r.originalLines} → ${r.keptLines} 行 / lines  (${r.sizeMb.toFixed(1)} MB → ${r.trimmedSizeMb.toFixed(1)} MB)\n\n` +
-          `备份位置 / Backup: ${r.backupPath}\n\n关闭并重新打开 CC 对话面板以生效 / Close and reopen CC chat panel to reload.`,
+          `✓ 裁剪副本已创建 / Trim copy created: ${r.originalLines} → ${r.keptLines} 行 / lines  (${r.sizeMb.toFixed(1)} MB → ${r.trimmedSizeMb.toFixed(1)} MB)\n\n` +
+          `原对话不变，裁剪版标题为 "...(trim)"，刷新列表即可看到 / Original unchanged. Trimmed copy titled "...(trim)" — refresh to see it.`,
           { modal: true }
         );
       } catch (err) {
@@ -1334,7 +1334,7 @@ function getSessionDisplayTitle(jsonlPath: string): string {
 function trimSession(
   jsonlPath: string,
   keepRecentMessages: number = 400
-): { keptLines: number; originalLines: number; sizeMb: number; trimmedSizeMb: number; backupPath: string } {
+): { keptLines: number; originalLines: number; sizeMb: number; trimmedSizeMb: number; newFilePath: string; newSessionId: string } {
   const raw = fs.readFileSync(jsonlPath, 'utf8');
   const lines = raw.split('\n');
   const originalLines = lines.filter((l) => l.trim()).length;
@@ -1346,8 +1346,8 @@ function trimSession(
   });
 
   // Classify each non-empty line
-  const msgLines: number[] = [];   // indices of user/assistant message lines
-  const initLines: number[] = [];  // everything else (system, summaries, etc.)
+  const msgLines: number[] = [];
+  const initLines: number[] = [];
 
   for (let i = 0; i < parsed.length; i++) {
     const obj = parsed[i].obj;
@@ -1360,7 +1360,7 @@ function trimSession(
     }
   }
 
-  // Keep last keepRecentMessages message lines, ensuring we don't start with assistant
+  // Keep last keepRecentMessages message lines, start from a user turn
   let recent = msgLines.slice(-keepRecentMessages);
   while (recent.length > 0) {
     const firstObj = parsed[recent[0]].obj;
@@ -1369,23 +1369,55 @@ function trimSession(
     recent = recent.slice(1);
   }
 
-  // Build output: init lines + recent message lines, preserving original order
+  // Build selected lines preserving original order
   const keepSet = new Set([...initLines, ...recent]);
-  const outLines: string[] = [];
+  const selectedLines: Record<string, unknown>[] = [];
   for (let i = 0; i < parsed.length; i++) {
-    if (!parsed[i].raw.trim()) continue;  // skip blank
-    if (keepSet.has(i)) outLines.push(parsed[i].raw);
+    if (!parsed[i].raw.trim()) continue;
+    if (keepSet.has(i) && parsed[i].obj) selectedLines.push(parsed[i].obj!);
   }
 
-  // Backup original
-  const ts = new Date().toISOString().replace(/[:.]/g, '-').slice(0, 19);
-  const backupPath = `${jsonlPath}.bak-${ts}`;
-  fs.copyFileSync(jsonlPath, backupPath);
+  // Generate new session ID and remap all UUIDs (same approach as injectSession)
+  const crypto = require('crypto') as typeof import('crypto');
+  const newSessionId: string = crypto.randomUUID();
+  const uuidMap = new Map<string, string>();
+
+  const outLines: string[] = [];
+  let titleSet = false;
+
+  for (const obj of selectedLines) {
+    const cloned = { ...obj } as Record<string, unknown>;
+
+    // Remap uuid
+    const oldUuid = cloned.uuid as string | undefined;
+    const newUuid: string = crypto.randomUUID();
+    if (oldUuid) uuidMap.set(oldUuid, newUuid);
+    cloned.uuid = newUuid;
+
+    // Remap parentUuid
+    const oldParent = cloned.parentUuid as string | null | undefined;
+    if (typeof oldParent === 'string' && uuidMap.has(oldParent)) {
+      cloned.parentUuid = uuidMap.get(oldParent)!;
+    }
+
+    // Stamp new sessionId
+    cloned.sessionId = newSessionId;
+
+    // Set customTitle on first line that has one (or first line overall)
+    if (!titleSet) {
+      const originalTitle = (cloned.customTitle as string | undefined) || getSessionDisplayTitle(jsonlPath);
+      cloned.customTitle = `${originalTitle} (trim)`;
+      titleSet = true;
+    }
+
+    outLines.push(JSON.stringify(cloned));
+  }
 
-  // Overwrite in-place
-  fs.writeFileSync(jsonlPath, outLines.join('\n') + '\n', 'utf8');
-  const trimmedSizeMb = fs.statSync(jsonlPath).size / 1024 / 1024;
+  // Write new file alongside original (same project dir, new UUID filename)
+  const newFilePath = path.join(path.dirname(jsonlPath), `${newSessionId}.jsonl`);
+  fs.writeFileSync(newFilePath, outLines.join('\n') + '\n', 'utf8');
+  const trimmedSizeMb = fs.statSync(newFilePath).size / 1024 / 1024;
 
-  return { keptLines: outLines.length, originalLines, sizeMb, trimmedSizeMb, backupPath };
+  return { keptLines: outLines.length, originalLines, sizeMb, trimmedSizeMb, newFilePath, newSessionId };
 }