feat: detect missing project paths + remap (port of upstream #35)

main.js

@@ -1,5 +1,5 @@
 const { app, BrowserWindow, dialog, ipcMain, Menu, screen, shell } = require('electron');
 const { Worker } = require('worker_threads');
 const { execFile } = require('child_process');
 const path = require('path');
 const fs = require('fs');
@@ -16,7 +16,7 @@
 }
 
 // getFolderIndexMtimeMs moved to session-cache.js
 const { startMcpServer, shutdownMcpServer, shutdownAll: shutdownAllMcp, resolvePendingDiff, rekeyMcpServer, cleanStaleLockFiles } = require('./mcp-bridge');
 const { fetchAndTransformUsage } = require('./claude-auth');
 log.transports.file.level = app.isPackaged ? 'info' : 'debug';
 log.transports.console.level = app.isPackaged ? 'info' : 'debug';
@@ -36,7 +36,7 @@
 );
 
 // Shell profiles → shell-profiles.js
 const { discoverShellProfiles, getShellProfiles, resolveShell, isWindows, isWslShell, windowsToWslPath, shellArgs } = require('./shell-profiles');
 const { startScheduler } = require('./schedule-runner');
 const { encodeProjectPath } = require('./encode-project-path');
 
@@ -73,7 +73,7 @@
   getMeta, getAllMeta, toggleStar, setName, setArchived,
   isCachePopulated, getAllCached, getCachedByFolder, getCachedByParent, getCachedFolder, getCachedSession, upsertCachedSessions,
   deleteCachedSession, deleteCachedFolder,
   getFolderMeta, getAllFolderMeta, setFolderMeta,
   upsertSearchEntries, updateSearchTitle, deleteSearchSession, deleteSearchFolder, deleteSearchType,
   searchByType, isSearchIndexPopulated, searchFtsRecreated,
   getSetting, setSetting, deleteSetting,
@@ -289,9 +289,9 @@
     setFolderMeta, getAllFolderMeta, getAllMeta, getAllCached, getSetting, getMeta, setName,
   },
 });
 const { readSessionFile, readFolderFromFilesystem, refreshFolder, populateCacheFromFilesystem,
         buildProjectsFromCache, notifyRendererProjectsChanged, sendStatus, populateCacheViaWorker } = sessionCache;
-const { resolveJsonlPath } = require('./read-session-file');
+const { resolveJsonlPath, enumerateSessionFiles } = require('./read-session-file');
 
 
 // --- IPC: browse-folder ---
@@ -367,6 +367,84 @@
   }
 });
 
+// --- IPC: remap-project ---
+
+/**
+ * Atomically rewrite cwd occurrences of oldPath → newPath in a single JSONL
+ * file. Uses a .tmp sibling + rename for crash safety. On any failure the .tmp
+ * orphan is cleaned up so it cannot block a future remap attempt.
+ */
+function rewriteJsonlAtomic(filePath, oldPath, newPath) {
+  const tmp = filePath + '.tmp';
+  try {
+    const content = fs.readFileSync(filePath, 'utf8');
+    const updated = content.split('\n').map(line => {
+      if (!line) return line;
+      try {
+        const parsed = JSON.parse(line);
+        if (parsed.cwd === oldPath) {
+          parsed.cwd = newPath;
+          return JSON.stringify(parsed);
+        }
+      } catch {}
+      return line;
+    }).join('\n');
+    fs.writeFileSync(tmp, updated);
+    fs.renameSync(tmp, filePath);
+  } catch (err) {
+    try { fs.unlinkSync(tmp); } catch {}
+    throw err;
+  }
+}
+
+ipcMain.handle('remap-project', (_event, oldPath, newPath) => {
+  try {
+    // Validate oldPath/newPath are strings (basic sanitisation)
+    if (typeof oldPath !== 'string' || typeof newPath !== 'string') {
+      return { error: 'Invalid arguments' };
+    }
+
+    // Re-check at handler entry: if oldPath came back, no remap is needed
+    if (fs.existsSync(oldPath)) {
+      return { error: 'Project path now exists — remap no longer needed' };
+    }
+
+    // Validate the new path exists and is a directory
+    let stat;
+    try { stat = fs.lstatSync(newPath); } catch { return { error: 'Path does not exist' }; }
+    if (!stat.isDirectory()) return { error: 'Path is not a directory' };
+
+    // Find the session folder for the old project path using the same encoding the CLI uses
+    const folder = encodeProjectPath(oldPath);
+    const folderPath = path.join(PROJECTS_DIR, folder);
+    if (!fs.existsSync(folderPath)) return { error: 'No session data found for this project' };
+
+    // Refuse if any active PTY session is running for this folder — rewriting
+    // files while a live claude process is appending them risks data loss
+    // (our snapshot + rename would silently drop lines appended between read
+    // and rename). The user must stop all sessions for this project first.
+    for (const [, session] of activeSessions) {
+      if (!session.exited && encodeProjectPath(session.projectPath) === folder) {
+        return { error: 'Active sessions for this project — stop them first' };
+      }
+    }
+
+    // Rewrite cwd in all session JSONL files (top-level + subagents) so
+    // `claude --resume` from CLI also picks up the new path.
+    const sessionFiles = enumerateSessionFiles(folderPath);
+    for (const { filePath } of sessionFiles) {
+      rewriteJsonlAtomic(filePath, oldPath, newPath);
+    }
+
+    // Refresh the folder cache so the new path takes effect in the UI
+    refreshFolder(folder);
+    notifyRendererProjectsChanged();
+    return { ok: true };
+  } catch (err) {
+    return { error: err.message };
+  }
+});
+
 // --- IPC: delete-worktree ---
 // Validated path pattern: <project>/.<segment>/[worktrees/]<name>
 // Matches .claude/worktrees/<n>, .claude-worktrees/<n>, .worktrees/<n>
@@ -1305,7 +1383,7 @@
   const shellExtraArgs = [...(shellProfile.args || [])];
   const isWsl = isWslShell(shell);
   // For WSL, convert Windows path to /mnt/ path and pass via --cd;
   // the spawn cwd must remain a valid Windows path for wsl.exe itself.
   if (isWsl) {
     const wslCwd = windowsToWslPath(projectPath);
     shellExtraArgs.unshift('--cd', wslCwd);

preload.js

@@ -44,6 +44,7 @@ contextBridge.exposeInMainWorld('api', {
   browseFolder: () => ipcRenderer.invoke('browse-folder'),
   addProject: (projectPath) => ipcRenderer.invoke('add-project', projectPath),
   removeProject: (projectPath) => ipcRenderer.invoke('remove-project', projectPath),
+  remapProject: (oldPath, newPath) => ipcRenderer.invoke('remap-project', oldPath, newPath),
   deleteWorktree: (worktreePath) => ipcRenderer.invoke('delete-worktree', worktreePath),
   worktreeStatus: (worktreePath) => ipcRenderer.invoke('worktree-status', worktreePath),
   openExternal: (url) => ipcRenderer.invoke('open-external', url),

public/app.js

@@ -794,6 +794,7 @@ async function launchNewSession(project, sessionOptions) {
   if (!result.ok) {
     entry.terminal.write(`\r\nError: ${result.error}\r\n`);
     entry.closed = true;
+    showSession(sessionId);
     return;
   }
   if (typeof setSessionMcpActive === 'function') setSessionMcpActive(sessionId, !!result.mcpActive);
@@ -860,6 +861,7 @@ async function openSession(session, customOptions) {
   if (!result.ok) {
     entry.terminal.write(`\r\nError: ${result.error}\r\n`);
     entry.closed = true;
+    showSession(sessionId);
     return;
   }
   if (typeof setSessionMcpActive === 'function') setSessionMcpActive(sessionId, !!result.mcpActive);

public/sidebar.js

@@ -474,14 +474,15 @@ function renderProjects(projects, resort) {
 
     // Build DOM
     const group = document.createElement('div');
-    group.className = 'project-group';
+    group.className = 'project-group' + (project.missing ? ' missing' : '');
     group.id = fId;
 
     const header = document.createElement('div');
     header.className = 'project-header';
     header.id = 'ph-' + fId;
     const shortName = project.projectPath.split('/').filter(Boolean).slice(-2).join('/');
-    header.innerHTML = `<span class="arrow">&#9660;</span> <span class="project-name">${shortName}</span>`;
+    const missingIcon = project.missing ? '<svg class="project-missing-icon" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M10.29 3.86L1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z"/><line x1="12" y1="9" x2="12" y2="13"/><line x1="12" y1="17" x2="12.01" y2="17"/></svg> ' : '';
+    header.innerHTML = `<span class="arrow">&#9660;</span> ${missingIcon}<span class="project-name">${escapeHtml(shortName)}</span>`;
 
     const scheduleBtn = document.createElement('button');
     scheduleBtn.className = 'project-schedule-btn';
@@ -501,6 +502,14 @@ function renderProjects(projects, resort) {
     archiveGroupBtn.innerHTML = ICONS.archive(18);
     header.appendChild(archiveGroupBtn);
 
+    if (project.missing) {
+      const remapBtn = document.createElement('button');
+      remapBtn.className = 'project-remap-btn';
+      remapBtn.title = 'Change project path';
+      remapBtn.innerHTML = '<svg width="12" height="12" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"><path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/><polyline points="17 8 12 3 7 8"/><line x1="12" y1="3" x2="12" y2="15"/></svg>';
+      header.appendChild(remapBtn);
+    }
+
     const newBtn = document.createElement('button');
     newBtn.className = 'project-new-btn';
     newBtn.innerHTML = '<svg width="12" height="12" viewBox="0 0 12 12" fill="none" stroke="currentColor" stroke-width="1.5"><line x1="6" y1="2" x2="6" y2="10"/><line x1="2" y1="6" x2="10" y2="6"/></svg>';
@@ -509,8 +518,10 @@ function renderProjects(projects, resort) {
 
     const sessionsList = buildSessionsList(fId, visible, older, subagentIndex, project.projectPath);
 
-    // Auto-collapse if most recent session is older than threshold, or project matched with no sessions
-    if (project._projectMatchedOnly) {
+    // Auto-collapse if project path is missing, most recent session is older than threshold, or project matched with no sessions
+    if (project.missing) {
+      header.classList.add('collapsed');
+    } else if (project._projectMatchedOnly) {
       header.classList.add('collapsed');
     } else if (searchMatchIds === null && !showStarredOnly && !showRunningOnly) {
       const mostRecent = filtered[0]?.modified;
@@ -689,8 +700,24 @@ function rebindSidebarEvents(projects) {
         loadProjects();
       };
     }
+    const remapBtn = header.querySelector('.project-remap-btn');
+    if (remapBtn) {
+      remapBtn.onclick = async (e) => {
+        e.stopPropagation();
+        const newPath = await window.api.browseFolder();
+        if (!newPath) return;
+        const projectShortName = project.projectPath.split('/').filter(Boolean).slice(-2).join('/');
+        if (!confirm(`Remap ${projectShortName} to:\n${newPath}?`)) return;
+        const result = await window.api.remapProject(project.projectPath, newPath);
+        if (result.error) {
+          alert('Failed to remap: ' + result.error);
+        } else {
+          loadProjects();
+        }
+      };
+    }
     header.onclick = (e) => {
-      if (e.target.closest('.project-new-btn') || e.target.closest('.project-archive-btn') || e.target.closest('.project-settings-btn') || e.target.closest('.project-schedule-btn')) return;
+      if (e.target.closest('.project-new-btn') || e.target.closest('.project-archive-btn') || e.target.closest('.project-settings-btn') || e.target.closest('.project-schedule-btn') || e.target.closest('.project-remap-btn')) return;
       header.classList.toggle('collapsed');
     };
   }
@@ -790,6 +817,14 @@ function rebindSidebarEvents(projects) {
     const session = sessionMap.get(sessionId);
     if (!session) return;
 
+    // Sessions under missing projects can't be opened — the path no longer exists
+    if (item.closest('.project-group.missing')) {
+      item.classList.add('disabled');
+      item.title = 'Project path no longer exists — use "Change path" to fix';
+      item.onclick = () => {};
+      return;
+    }
+
     item.onclick = () => {
       if (item.dataset.subagent && session.parentSessionId) {
         showSubagentTranscript(session);

public/style.css

@@ -487,6 +487,40 @@ body { display: flex; flex-direction: column; }
   display: none;
 }
 
+/* Missing project path */
+.project-group.missing {
+  opacity: 0.55;
+}
+.project-group.missing:hover {
+  opacity: 0.8;
+}
+.project-missing-icon {
+  color: #e8a838;
+  vertical-align: middle;
+  margin-right: 2px;
+  flex-shrink: 0;
+}
+.project-remap-btn {
+  background: none;
+  border: none;
+  color: #e8a838;
+  cursor: pointer;
+  padding: 2px 4px;
+  border-radius: 4px;
+  display: none;
+  align-items: center;
+}
+.project-group.missing .project-remap-btn {
+  display: inline-flex;
+}
+.project-remap-btn:hover {
+  background: rgba(232, 168, 56, 0.15);
+}
+.session-item.disabled {
+  opacity: 0.4;
+  cursor: not-allowed;
+}
+
 /* Worktree nested groups */
 .worktree-group {
   margin-left: 12px;

session-cache.js

@@ -312,6 +312,7 @@ function buildProjectsFromCache(showArchived) {
         folder: encodeProjectPath(row.projectPath),
         projectPath: row.projectPath,
         sessions: [],
+        missing: !fs.existsSync(row.projectPath),
       });
     }
     projectMap.get(row.projectPath).sessions.push(s);
@@ -339,6 +340,7 @@ function buildProjectsFromCache(showArchived) {
           folder: encodeProjectPath(projectPath),
           projectPath,
           sessions: [],
+          missing: !fs.existsSync(projectPath),
         });
       }
     }
@@ -375,6 +377,9 @@ function buildProjectsFromCache(showArchived) {
   }
 
   projects.sort((a, b) => {
+    // Missing projects go to the bottom
+    if (a.missing && !b.missing) return 1;
+    if (!a.missing && b.missing) return -1;
     // Empty projects go to the bottom
     if (a.sessions.length === 0 && b.sessions.length > 0) return 1;
     if (b.sessions.length === 0 && a.sessions.length > 0) return -1;