fix(terminal): drop native ARGV0 for bun-pty via env -u

bun-pty merges the OS environ into PTY children, so deleting ARGV0 from the
JS env object alone left the AppImage path in the shell. Wrap Linux PTY
spawns with env -u ARGV0, clear native ARGV0 under Bun via libc unsetenv,
and always clear process.env even when no login-shell snapshot exists.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/electron/main.mjs

@@ -1374,7 +1374,7 @@ const loadShellEnv = () => {
 
 // Merge the user's login-shell env (PATH, etc.) into this process before we
 import { pathLooksUserConfigured, mergePathValues } from '@openchamber/web/server/lib/opencode/path-utils.js';
-import { stripAppImageArgv0Leak } from '@openchamber/web/server/lib/inherited-env.js';
+import { clearAppImageArgv0FromProcessEnv } from '@openchamber/web/server/lib/inherited-env.js';
 
 // import/start the server in-process. The server and its children (opencode
 // CLI, git, etc.) inherit process.env directly now — there is no sidecar
@@ -1382,7 +1382,7 @@ import { stripAppImageArgv0Leak } from '@openchamber/web/server/lib/inherited-en
 const inheritUserShellEnv = () => {
   // Clear before probing/merging so login-shell snapshots and children never
   // inherit the AppImage path as argv[0] via zsh's ARGV0 parameter (#2588).
-  stripAppImageArgv0Leak(process.env);
+  clearAppImageArgv0FromProcessEnv();
 
   const shellEnv = loadShellEnv();
   if (!shellEnv) return;

packages/web/server/lib/inherited-env.js

@@ -9,6 +9,11 @@
  * See openchamber/openchamber#2588 and pingdotgg/t3code#2509.
  */
 
+import { createRequire } from 'node:module';
+import { existsSync } from 'node:fs';
+
+const LINUX_ENV_BINARIES = ['/usr/bin/env', '/bin/env'];
+
 /**
  * Remove AppImage `ARGV0` from a mutable env object (or `process.env`).
  * @param {NodeJS.ProcessEnv | Record<string, string | undefined> | null | undefined} env
@@ -21,3 +26,49 @@ export function stripAppImageArgv0Leak(env) {
   }
   return env;
 }
+
+/**
+ * Clear AppImage `ARGV0` from this process.
+ *
+ * Bun keeps a native environ that `bun-pty` inherits even after
+ * `delete process.env.ARGV0`. On Linux under Bun we also call libc `unsetenv`.
+ */
+export function clearAppImageArgv0FromProcessEnv() {
+  delete process.env.ARGV0;
+  if (process.platform !== 'linux' || typeof Bun === 'undefined') return;
+  try {
+    const require = createRequire(import.meta.url);
+    const { dlopen } = require('bun:ffi');
+    const libc = dlopen('libc.so.6', {
+      unsetenv: { args: ['cstring'], returns: 'i32' },
+    });
+    libc.symbols.unsetenv(Buffer.from('ARGV0\0'));
+  } catch {
+    // Node/Electron and environments without bun:ffi rely on explicit child envs.
+  }
+}
+
+/**
+ * Resolve a Linux PTY launch that drops native `ARGV0` before the shell starts.
+ *
+ * `bun-pty` merges the OS environ into the child, so deleting `ARGV0` from the
+ * JS env object alone is not enough. Wrapping with `env -u ARGV0` unsets it
+ * before execing the real shell. No-op on non-Linux platforms.
+ *
+ * @param {string} executable
+ * @param {string[]} args
+ * @returns {{ executable: string, args: string[] }}
+ */
+export function resolveLinuxPtyLaunch(executable, args = []) {
+  if (process.platform !== 'linux') {
+    return { executable, args };
+  }
+  const envBinary = LINUX_ENV_BINARIES.find((candidate) => existsSync(candidate));
+  if (!envBinary) {
+    return { executable, args };
+  }
+  return {
+    executable: envBinary,
+    args: ['-u', 'ARGV0', executable, ...args],
+  };
+}

packages/web/server/lib/inherited-env.test.js

@@ -1,5 +1,9 @@
 import { describe, expect, it } from 'vitest';
-import { stripAppImageArgv0Leak } from './inherited-env.js';
+import {
+  clearAppImageArgv0FromProcessEnv,
+  resolveLinuxPtyLaunch,
+  stripAppImageArgv0Leak,
+} from './inherited-env.js';
 
 describe('stripAppImageArgv0Leak', () => {
   it('removes ARGV0 from a child env object', () => {
@@ -27,3 +31,35 @@ describe('stripAppImageArgv0Leak', () => {
     expect(stripAppImageArgv0Leak(undefined)).toBeUndefined();
   });
 });
+
+describe('clearAppImageArgv0FromProcessEnv', () => {
+  it('removes ARGV0 from process.env', () => {
+    const previous = process.env.ARGV0;
+    process.env.ARGV0 = '/path/to/OpenChamber.AppImage';
+    try {
+      clearAppImageArgv0FromProcessEnv();
+      expect(process.env.ARGV0).toBeUndefined();
+    } finally {
+      if (previous === undefined) delete process.env.ARGV0;
+      else process.env.ARGV0 = previous;
+    }
+  });
+});
+
+describe('resolveLinuxPtyLaunch', () => {
+  it('wraps the shell with env -u ARGV0 on Linux', () => {
+    if (process.platform !== 'linux') return;
+    expect(resolveLinuxPtyLaunch('/bin/zsh', ['-l'])).toEqual({
+      executable: expect.stringMatching(/\/env$/),
+      args: ['-u', 'ARGV0', '/bin/zsh', '-l'],
+    });
+  });
+
+  it('leaves non-Linux launches unchanged', () => {
+    if (process.platform === 'linux') return;
+    expect(resolveLinuxPtyLaunch('/bin/zsh', ['-l'])).toEqual({
+      executable: '/bin/zsh',
+      args: ['-l'],
+    });
+  });
+});

packages/web/server/lib/opencode/env-runtime.js

@@ -2,6 +2,7 @@ import { spawnSync } from 'node:child_process';
 import fs from 'node:fs';
 import os from 'node:os';
 import path from 'node:path';
+import { clearAppImageArgv0FromProcessEnv } from '../inherited-env.js';
 import { mergePathValues } from './path-utils.js';
 
 export const createOpenCodeEnvRuntime = (deps) => {
@@ -227,6 +228,10 @@ export const createOpenCodeEnvRuntime = (deps) => {
   };
 
   const applyLoginShellEnvSnapshot = () => {
+    // Always clear AppImage ARGV0, even when no login-shell snapshot is available.
+    // Otherwise a leaked process.env.ARGV0 survives into later child spawns (#2588).
+    clearAppImageArgv0FromProcessEnv();
+
     const snapshot = getLoginShellEnvSnapshot();
     if (!snapshot) {
       return;
@@ -244,9 +249,6 @@ export const createOpenCodeEnvRuntime = (deps) => {
       process.env[key] = value;
     }
 
-    // AppImage ARGV0 must never remain on process.env (zsh rewrites argv[0]; #2588).
-    delete process.env.ARGV0;
-
     const currentPath = process.env.PATH || '';
     const shellPath = snapshot.PATH || '';
     if (!shellPath) {

packages/web/server/lib/opencode/env-runtime.test.js

@@ -153,6 +153,21 @@ describe('OpenCode env runtime', () => {
     }
   });
 
+  it('clears AppImage ARGV0 even when no login-shell snapshot is available', () => {
+    const previousArgv0 = process.env.ARGV0;
+    process.env.ARGV0 = '/path/to/OpenChamber.AppImage';
+    const { runtime, state } = createRuntime({});
+    state.cachedLoginShellEnvSnapshot = null;
+
+    try {
+      runtime.applyLoginShellEnvSnapshot();
+      expect(process.env.ARGV0).toBeUndefined();
+    } finally {
+      if (previousArgv0 === undefined) delete process.env.ARGV0;
+      else process.env.ARGV0 = previousArgv0;
+    }
+  });
+
   it('throws a specific error for a missing configured OpenCode binary in strict mode', async () => {
     const { runtime } = createRuntime({ opencodeBinary: '/missing/opencode' });
 

packages/web/server/lib/terminal/DOCUMENTATION.md

@@ -24,7 +24,7 @@ HTTP remains the authenticated command plane for create, resize, appearance upda
 - Concurrent creates for one ID are single-flight only when working directory and shell preference match. Existing IDs cannot be reused for another working directory.
 - Dimensions are bounded to 1-1000 columns and 1-500 rows; input is capped at 64 KiB.
 - PTY children explicitly clear `NODE_CHANNEL_FD`; daemon IPC descriptors are host-private and invalid after PTY descriptor cleanup.
-- PTY children also strip AppImage `ARGV0` (and other host-private shell vars such as `ELECTRON_RUN_AS_NODE`, `BASH_ENV`, `ENV`, `BASH_XTRACEFD`). An exported `ARGV0` makes zsh rewrite argv[0] for every external command, which breaks Python venv detection and other argv[0]/$0 consumers while leaving `/proc/self/exe` correct.
+- PTY children also strip AppImage `ARGV0` (and other host-private shell vars such as `ELECTRON_RUN_AS_NODE`, `BASH_ENV`, `ENV`, `BASH_XTRACEFD`). An exported `ARGV0` makes zsh rewrite argv[0] for every external command, which breaks Python venv detection and other argv[0]/$0 consumers while leaving `/proc/self/exe` correct. On Linux, PTY spawn is wrapped with `env -u ARGV0` because `bun-pty` merges the native OS environ and would otherwise reintroduce `ARGV0` after a JS-only delete.
 - `GET /api/terminal/shells` reports shell IDs available on the active server using the same augmented PATH provided to spawned PTYs, plus whether each executable has a supported login-mode argument. `auto` preserves environment/platform fallback order; an explicit unavailable shell fails creation instead of silently running a different shell. Login mode is opt-in and uses only built-in arguments for known shells. Preference changes affect new sessions and explicit restarts, not running PTYs.
 - PTY data and exit callbacks enter one FIFO queue. Stale callbacks from replaced processes are ignored.
 - Scrollback is retained on the server and capped at 512 KiB with UTF-8-safe trimming. Device-status, device-attribute, cursor-position reply, and color-query exchanges are removed from replay history with incomplete control sequences carried across PTY chunks; live output remains byte-for-byte unchanged.

packages/web/server/lib/terminal/runtime.js

@@ -10,7 +10,7 @@ import {
 import { sanitizeTerminalHistoryChunk } from './history.js';
 import { consumeTerminalThemeQueries, terminalThemeModeReport } from './theme-response.js';
 import { createTerminalShellResolver, getTerminalShellLoginArgs, normalizeTerminalShell } from './shells.js';
-import { stripAppImageArgv0Leak } from '../inherited-env.js';
+import { stripAppImageArgv0Leak, resolveLinuxPtyLaunch } from '../inherited-env.js';
 
 const MAX_SESSIONS = 20;
 const MAX_HISTORY_BYTES = 512 * 1024;
@@ -68,9 +68,11 @@ export function createTerminalRuntime({
         env.NODE_CHANNEL_FD = '';
         delete env.BASH_XTRACEFD; delete env.BASH_ENV; delete env.ENV; delete env.ELECTRON_RUN_AS_NODE;
         // AppImage exports ARGV0; zsh would otherwise rewrite argv[0] for every command (#2588).
+        // bun-pty also merges the native OS environ, so wrap with `env -u ARGV0` on Linux.
         stripAppImageArgv0Leak(env);
+        const launch = resolveLinuxPtyLaunch(executable, args);
         const options = { name: 'xterm-256color', cwd, cols, rows, env, ...(process.platform === 'win32' ? { useConpty: true } : {}) };
-        return { process: provider.spawn(executable, args, options), backend: provider.backend, shell: resolvedShell.id, loginShell };
+        return { process: provider.spawn(launch.executable, launch.args, options), backend: provider.backend, shell: resolvedShell.id, loginShell };
       } catch (error) { lastError = error; }
     }
     throw lastError ?? new Error('No executable shell found');

packages/web/server/lib/terminal/runtime.test.js

@@ -156,6 +156,10 @@ describe('terminal runtime', () => {
       expect(harness.processes[0].options.env.NODE_CHANNEL_FD).toBe('');
       expect(harness.processes[0].options.env).not.toHaveProperty('ARGV0');
       expect(harness.processes[0].options.env).not.toHaveProperty('ELECTRON_RUN_AS_NODE');
+      if (process.platform === 'linux') {
+        expect(harness.processes[0].shell).toMatch(/\/env$/);
+        expect(harness.processes[0].args.slice(0, 3)).toEqual(['-u', 'ARGV0', expect.any(String)]);
+      }
       harness.processes[0].emitData('\u001b[?2031h\u001b]10;?\u0007\u001b]11;?\u0007');
       expect(harness.processes[0].writes).toEqual(['\u001b]10;rgb:1b1b/1b1b/1b1b\u001b\\', '\u001b]11;rgb:fafa/f8f8/f0f0\u001b\\']);
 
@@ -184,6 +188,11 @@ describe('terminal runtime', () => {
       await harness.routes.post.get('/api/terminal/create')({ body: { sessionId: 'term-argv0', cwd: '/repo', cols: 80, rows: 24 } }, response);
       expect(response.statusCode).toBe(200);
       expect(harness.processes[0].options.env).not.toHaveProperty('ARGV0');
+      if (process.platform === 'linux') {
+        expect(harness.processes[0].shell).toMatch(/\/env$/);
+        expect(harness.processes[0].args[0]).toBe('-u');
+        expect(harness.processes[0].args[1]).toBe('ARGV0');
+      }
     } finally {
       if (previousArgv0 === undefined) delete process.env.ARGV0;
       else process.env.ARGV0 = previousArgv0;
@@ -216,14 +225,24 @@ describe('terminal runtime', () => {
       const created = createResponse();
       await harness.routes.post.get('/api/terminal/create')({ body: { sessionId: 'term-shell', cwd: '/repo', shell: 'zsh', loginShell: true } }, created);
       expect(created.statusCode).toBe(200);
-      expect(harness.processes[0].shell).toBe('/bin/zsh');
-      expect(harness.processes[0].args).toEqual(['-l']);
+      if (process.platform === 'linux') {
+        expect(harness.processes[0].shell).toMatch(/\/env$/);
+        expect(harness.processes[0].args).toEqual(['-u', 'ARGV0', '/bin/zsh', '-l']);
+      } else {
+        expect(harness.processes[0].shell).toBe('/bin/zsh');
+        expect(harness.processes[0].args).toEqual(['-l']);
+      }
 
       const restarted = createResponse();
       await harness.routes.post.get('/api/terminal/:sessionId/restart')({ params: { sessionId: 'term-shell' }, body: { shell: 'bash', loginShell: true } }, restarted);
       expect(restarted.statusCode).toBe(200);
-      expect(harness.processes[1].shell).toBe('/bin/bash');
-      expect(harness.processes[1].args).toEqual(['-l']);
+      if (process.platform === 'linux') {
+        expect(harness.processes[1].shell).toMatch(/\/env$/);
+        expect(harness.processes[1].args).toEqual(['-u', 'ARGV0', '/bin/bash', '-l']);
+      } else {
+        expect(harness.processes[1].shell).toBe('/bin/bash');
+        expect(harness.processes[1].args).toEqual(['-l']);
+      }
     } finally { await harness.runtime.shutdown(); }
   });