Fix windows launching and shell detection (#11)

Author: nedtwigg

docs/specs/vscode.md

@@ -144,12 +144,13 @@ All types defined in `message-types.ts`. Webview-side handling in `vscode-adapte
 
 | Message | Purpose |
 |---------|---------|
-| `pty:spawn` | Create new PTY (id, optional cols/rows/cwd) |
+| `pty:spawn` | Create new PTY (id, optional cols/rows/cwd/shell/args) |
 | `pty:input` | Write data to PTY |
 | `pty:resize` | Resize PTY dimensions |
 | `pty:kill` | Kill PTY and release ownership |
 | `pty:getCwd` | Query PTY working directory (request-response via requestId) |
 | `pty:getScrollback` | Query PTY scrollback buffer (request-response via requestId) |
+| `pty:getShells` | Query available shells (request-response via requestId) |
 | `mouseterm:init` | Trigger reconnection: get PTY list + replay data |
 | `mouseterm:saveState` | Frontend persisting session state |
 | `mouseterm:flushSessionSaveDone` | Ack for deactivate-triggered flush (matched by requestId) |
@@ -175,6 +176,7 @@ All types defined in `message-types.ts`. Webview-side handling in `vscode-adapte
 | `pty:replay` | Buffered output since spawn (response to `mouseterm:init`) |
 | `pty:cwd` | CWD query response (matched by requestId) |
 | `pty:scrollback` | Scrollback query response (matched by requestId) |
+| `pty:shells` | Available shells list response (matched by requestId) |
 | `mouseterm:flushSessionSave` | Request webview to save state now (deactivate trigger, matched by requestId) |
 | `alarm:state` | Alarm state change (status, todo, attentionDismissedRing) |
 

lib/src/components/Pond.tsx

@@ -32,6 +32,7 @@ import {
   toggleSessionTodo,
   destroyTerminal,
   swapTerminals,
+  setPendingShellOpts,
   type SessionStatus,
 } from '../lib/terminal-registry';
 import { resolvePanelElement, findPanelInDirection, findRestoreNeighbor, type DetachDirection } from '../lib/spatial-nav';
@@ -1690,10 +1691,17 @@ export function Pond({
 
   // Listen for external "new terminal" requests (e.g. from the standalone AppBar)
   useEffect(() => {
-    const handler = () => {
+    const handler = (e: Event) => {
       const api = apiRef.current;
       if (!api) return;
+      const detail = (e as CustomEvent).detail;
       const newId = generatePaneId();
+
+      // Store shell options so getOrCreateTerminal picks them up on mount
+      if (detail?.shell) {
+        setPendingShellOpts(newId, { shell: detail.shell, args: detail.args });
+      }
+
       const active = api.activePanel;
       let direction: 'right' | 'below' = 'right';
       if (active) {

lib/src/lib/platform/fake-adapter.ts

@@ -66,6 +66,10 @@ export class FakePtyAdapter implements PlatformAdapter {
     });
   }
 
+  async getAvailableShells(): Promise<{ name: string; path: string; args?: string[] }[]> {
+    return [{ name: 'fake-shell', path: '/bin/fake', args: [] }];
+  }
+
   spawnPty(id: string): void {
     this.terminals.add(id);
     const scenario = this.scenarioMap.get(id) ?? this.defaultScenario;

lib/src/lib/platform/types.ts

@@ -13,8 +13,11 @@ export interface PlatformAdapter {
   init(): Promise<void>;
   shutdown(): void;
 
+  // Shell detection
+  getAvailableShells(): Promise<{ name: string; path: string; args?: string[] }[]>;
+
   // PTY operations
-  spawnPty(id: string, options?: { cols?: number; rows?: number; cwd?: string }): void;
+  spawnPty(id: string, options?: { cols?: number; rows?: number; cwd?: string; shell?: string; args?: string[] }): void;
   writePty(id: string, data: string): void;
   resizePty(id: string, cols: number, rows: number): void;
   killPty(id: string): void;

lib/src/lib/platform/vscode-adapter.ts

@@ -80,7 +80,16 @@ export class VSCodeAdapter implements PlatformAdapter {
     // No-op — the extension host handles cleanup
   }
 
-  spawnPty(id: string, options?: { cols?: number; rows?: number; cwd?: string }): void {
+  async getAvailableShells(): Promise<{ name: string; path: string; args?: string[] }[]> {
+    const result = await this.requestResponse(
+      'pty:getShells', 'pty:shells', {},
+      (msg) => msg.shells as { name: string; path: string; args?: string[] }[],
+      5000,
+    );
+    return result ?? [];
+  }
+
+  spawnPty(id: string, options?: { cols?: number; rows?: number; cwd?: string; shell?: string; args?: string[] }): void {
     this.vscode.postMessage({ type: 'pty:spawn', id, options });
   }
 

lib/src/lib/session-save.test.ts

@@ -24,6 +24,7 @@ function createPlatform(savedState: PersistedSession | null): PlatformAdapter {
     writePty: () => {},
     resizePty: () => {},
     killPty: () => {},
+    getAvailableShells: vi.fn(async () => []),
     getCwd: vi.fn(async () => '/tmp/live'),
     getScrollback: vi.fn(async () => 'echo hello\n'),
     onPtyData: () => {},

lib/src/lib/terminal-registry.ts

@@ -37,6 +37,7 @@ interface TerminalEntry {
 }
 
 const registry = new Map<string, TerminalEntry>();
+const pendingShellOpts = new Map<string, { shell?: string; args?: string[] }>();
 const primedSessionStates = new Map<string, Partial<SessionUiState>>();
 
 // --- Watch for VSCode theme changes and re-apply xterm themes ---
@@ -390,6 +391,14 @@ function setupTerminalEntry(id: string): TerminalEntry {
   return entry;
 }
 
+/**
+ * Store shell options for a terminal that will be created shortly.
+ * The options are consumed (deleted) by getOrCreateTerminal when the terminal mounts.
+ */
+export function setPendingShellOpts(id: string, opts: { shell?: string; args?: string[] }): void {
+  pendingShellOpts.set(id, opts);
+}
+
 /**
  * Get or create a terminal for the given pane ID.
  * The terminal is created once and persists across React mount/unmount cycles.
@@ -400,9 +409,17 @@ export function getOrCreateTerminal(id: string): TerminalEntry {
 
   const entry = setupTerminalEntry(id);
 
+  // Consume any pending shell options set before panel creation
+  const shellOpts = pendingShellOpts.get(id);
+  pendingShellOpts.delete(id);
+
   // Spawn PTY
   const dims = entry.fit.proposeDimensions();
-  getPlatform().spawnPty(id, { cols: dims?.cols || 80, rows: dims?.rows || 30 });
+  getPlatform().spawnPty(id, {
+    cols: dims?.cols || 80,
+    rows: dims?.rows || 30,
+    ...shellOpts,
+  });
 
   return entry;
 }

standalone/sidecar/main.js

@@ -27,6 +27,7 @@ rl.on('line', (line) => {
       case 'pty:requestInit': mgr.list(); break;
       case 'pty:getCwd':  mgr.getCwd(data.id, data.requestId); break;
       case 'pty:getScrollback': mgr.getScrollback(data.id, data.requestId); break;
+      case 'pty:getShells':  mgr.getShells(data.requestId); break;
       case 'pty:gracefulKillAll': mgr.gracefulKillAll(data.timeout); break;
       default: console.error(`[sidecar] Unknown event: ${event}`);
     }

standalone/sidecar/pty-core.js

@@ -1,7 +1,7 @@
 const fs = require('node:fs');
 const os = require('node:os');
 const path = require('node:path');
-const { execFileSync } = require('node:child_process');
+const { execFileSync, execSync } = require('node:child_process');
 
 function safeResolve(resolver) {
   try {
@@ -55,14 +55,15 @@ function directoryExists(cwd, fsModule = fs) {
 }
 
 function resolveSpawnConfig(options, runtime = {}) {
-  const { cols = 80, rows = 30, cwd } = options || {};
+  const { cols = 80, rows = 30, cwd, shell: explicitShell, args: explicitArgs } = options || {};
   const env = runtime.env || process.env;
   const platform = runtime.platform || process.platform;
   const osModule = runtime.osModule || os;
   const fsModule = runtime.fsModule || fs;
   const defaultCwd = resolveDefaultCwd(platform, env, osModule);
   const missingExplicitCwd = Boolean(cwd) && !directoryExists(cwd, fsModule);
-  const shell = resolveDefaultShell(platform, env);
+  const shell = explicitShell || resolveDefaultShell(platform, env);
+  const shellArgs = explicitArgs || resolveLoginArg(shell, platform);
 
   return {
     cols,
@@ -71,12 +72,146 @@ function resolveSpawnConfig(options, runtime = {}) {
     cwdWarning: missingExplicitCwd ? `unable to restore because directory ${cwd} was removed` : null,
     env: { ...env, TERM_PROGRAM: 'MouseTerm' },
     shell,
-    loginArg: resolveLoginArg(shell, platform),
+    shellArgs,
   };
 }
 
 module.exports.resolveSpawnConfig = resolveSpawnConfig;
 
+// ── Shell detection ────────────────────────────────────────────────────────
+
+function fileExists(filePath, fsModule = fs) {
+  try {
+    return fsModule.statSync(filePath).isFile();
+  } catch {
+    return false;
+  }
+}
+
+function detectWindowsShells(runtime = {}) {
+  const env = runtime.env || process.env;
+  const fsModule = runtime.fsModule || fs;
+  const execSyncFn = runtime.execSync || execSync;
+  const systemRoot = env.SystemRoot || env.SYSTEMROOT || 'C:\\Windows';
+  const shells = [];
+
+  // Windows PowerShell (built-in)
+  const winPowerShell = path.win32.join(systemRoot, 'System32', 'WindowsPowerShell', 'v1.0', 'powershell.exe');
+  if (fileExists(winPowerShell, fsModule)) {
+    shells.push({ name: 'Windows PowerShell', path: winPowerShell, args: [] });
+  }
+
+  // Command Prompt
+  const cmdPath = env.ComSpec || env.COMSPEC || path.win32.join(systemRoot, 'System32', 'cmd.exe');
+  if (fileExists(cmdPath, fsModule)) {
+    shells.push({ name: 'Command Prompt', path: cmdPath, args: [] });
+  }
+
+  // PowerShell Core (pwsh) — scan Program Files
+  const pwshDirs = [
+    path.win32.join(env.ProgramFiles || 'C:\\Program Files', 'PowerShell'),
+    path.win32.join(env['ProgramFiles(x86)'] || 'C:\\Program Files (x86)', 'PowerShell'),
+  ];
+  for (const dir of pwshDirs) {
+    try {
+      const versions = fsModule.readdirSync(dir).sort().reverse();
+      for (const ver of versions) {
+        const pwshPath = path.win32.join(dir, ver, 'pwsh.exe');
+        if (fileExists(pwshPath, fsModule)) {
+          shells.push({ name: 'PowerShell', path: pwshPath, args: [] });
+          break; // only add the newest version
+        }
+      }
+      if (shells.some((s) => s.name === 'PowerShell')) break;
+    } catch { /* dir doesn't exist */ }
+  }
+
+  // WSL distributions
+  try {
+    const wslExe = path.win32.join(systemRoot, 'System32', 'wsl.exe');
+    if (fileExists(wslExe, fsModule)) {
+      const raw = execSyncFn(`"${wslExe}" -l -q`, {
+        encoding: 'utf-16le',
+        stdio: ['ignore', 'pipe', 'ignore'],
+        timeout: 5000,
+      });
+      const distros = raw.split(/\r?\n/)
+        .map((line) => line.replace(/\0/g, '').trim())
+        .filter(Boolean);
+      for (const distro of distros) {
+        shells.push({ name: distro, path: wslExe, args: ['-d', distro] });
+      }
+    }
+  } catch { /* WSL not installed or no distros */ }
+
+  // Git Bash
+  const gitBashPaths = [
+    path.win32.join(env.ProgramFiles || 'C:\\Program Files', 'Git', 'bin', 'bash.exe'),
+    path.win32.join(env['ProgramFiles(x86)'] || 'C:\\Program Files (x86)', 'Git', 'bin', 'bash.exe'),
+  ];
+  for (const gbPath of gitBashPaths) {
+    if (fileExists(gbPath, fsModule)) {
+      shells.push({ name: 'Git Bash', path: gbPath, args: ['--login', '-i'] });
+      break;
+    }
+  }
+
+  // Visual Studio Developer shells
+  const vsBasePaths = [
+    env.ProgramFiles || 'C:\\Program Files',
+    env['ProgramFiles(x86)'] || 'C:\\Program Files (x86)',
+  ];
+  for (const base of vsBasePaths) {
+    const vsRoot = path.win32.join(base, 'Microsoft Visual Studio');
+    let years;
+    try { years = fsModule.readdirSync(vsRoot); } catch { continue; }
+    for (const year of years.sort().reverse()) {
+      let editions;
+      try { editions = fsModule.readdirSync(path.win32.join(vsRoot, year)); } catch { continue; }
+      for (const edition of editions) {
+        const toolsDir = path.win32.join(vsRoot, year, edition, 'Common7', 'Tools');
+
+        // Developer Command Prompt
+        const vsDevCmd = path.win32.join(toolsDir, 'VsDevCmd.bat');
+        if (fileExists(vsDevCmd, fsModule) && fileExists(cmdPath, fsModule)) {
+          shells.push({
+            name: `Developer Command Prompt for VS ${year}`,
+            path: cmdPath,
+            args: ['/k', vsDevCmd],
+          });
+        }
+
+        // Developer PowerShell
+        const launchScript = path.win32.join(toolsDir, 'Launch-VsDevShell.ps1');
+        if (fileExists(launchScript, fsModule) && fileExists(winPowerShell, fsModule)) {
+          shells.push({
+            name: `Developer PowerShell for VS ${year}`,
+            path: winPowerShell,
+            args: ['-NoExit', '-Command', `& { Import-Module "${launchScript}" }`],
+          });
+        }
+      }
+    }
+  }
+
+  return shells;
+}
+
+function detectAvailableShells(runtime = {}) {
+  const platform = runtime.platform || process.platform;
+  if (platform === 'win32') {
+    return detectWindowsShells(runtime);
+  }
+
+  // macOS / Linux: return $SHELL or /bin/sh
+  const env = runtime.env || process.env;
+  const shellPath = env.SHELL || '/bin/sh';
+  const name = path.posix.basename(shellPath);
+  return [{ name, path: shellPath, args: [] }];
+}
+
+module.exports.detectAvailableShells = detectAvailableShells;
+
 function parseCwdFromLsof(output, pid) {
   const lines = output.split(/\r?\n/);
   let inTargetProcess = false;
@@ -173,7 +308,7 @@ module.exports.create = function create(send, ptyModule) {
 
     let p;
     try {
-      p = pty.spawn(config.shell, config.loginArg, {
+      p = pty.spawn(config.shell, config.shellArgs, {
         name: 'xterm-256color',
         cols: config.cols,
         rows: config.rows,
@@ -267,5 +402,9 @@ module.exports.create = function create(send, ptyModule) {
     }, timeout);
   }
 
-  return { spawn, write, resize, kill, killAll, list, getCwd, getScrollback, gracefulKillAll };
+  function getShells(requestId) {
+    send('shells', { shells: detectAvailableShells(), requestId });
+  }
+
+  return { spawn, write, resize, kill, killAll, list, getCwd, getScrollback, gracefulKillAll, getShells };
 };