Fix zsh integration runtime file modes (#976)

packages/server/src/terminal/terminal.posix.test.ts

@@ -20,7 +20,7 @@ import {
 } from "node:fs";
 import { spawnSync } from "node:child_process";
 import { join } from "node:path";
-import { tmpdir } from "node:os";
+import { tmpdir, userInfo } from "node:os";
 
 const hasZsh = existsSync("/bin/zsh");
 
@@ -216,6 +216,13 @@ function lastNonEmptyLineIsPrompt(state: ReturnType<TerminalSession["getState"]>
   return last === "$";
 }
 
+function removeZshShellIntegrationRuntimeDir(): void {
+  rmSync(join(tmpdir(), `${userInfo().username || "unknown"}-paseo-zsh`), {
+    recursive: true,
+    force: true,
+  });
+}
+
 describe.skipIf(isPlatform("win32"))("terminal POSIX-only", () => {
   it("sets zsh wrapper env when spawning zsh", () => {
     const resolvedEnv = buildTerminalEnvironment({
@@ -233,6 +240,27 @@ describe.skipIf(isPlatform("win32"))("terminal POSIX-only", () => {
     expect(existsSync(join(resolvedEnv.ZDOTDIR, "paseo-integration.zsh"))).toBe(true);
   });
 
+  it("reuses zsh shell integration copied from read-only source files", () => {
+    const integrationSourceDir = mkdtempSync(join(tmpdir(), "paseo-zsh-readonly-source-"));
+    const tmpHome = mkdtempSync(join(tmpdir(), "paseo-zsh-readonly-home-"));
+    temporaryDirs.push(integrationSourceDir, tmpHome);
+    cpSync(resolveZshShellIntegrationDir(), integrationSourceDir, { recursive: true });
+    chmodSync(join(integrationSourceDir, ".zshenv"), 0o444);
+    chmodSync(join(integrationSourceDir, "paseo-integration.zsh"), 0o444);
+    removeZshShellIntegrationRuntimeDir();
+
+    const buildEnvironment = () =>
+      buildTerminalEnvironment({
+        shell: "/bin/zsh",
+        env: { HOME: tmpHome },
+        zshShellIntegrationDir: integrationSourceDir,
+      });
+
+    buildEnvironment();
+
+    expect(buildEnvironment).not.toThrow();
+  });
+
   describe("send input", () => {
     it("executes a simple echo command", async () => {
       const session = trackSession(

packages/server/src/terminal/terminal.ts

@@ -1,12 +1,13 @@
 import * as pty from "node-pty";
 import xterm, { type Terminal as TerminalType } from "@xterm/headless";
 import { randomUUID } from "crypto";
-import { chmodSync, copyFileSync, existsSync, mkdirSync, statSync } from "node:fs";
+import { chmodSync, existsSync, mkdirSync, readFileSync, statSync } from "node:fs";
 import { tmpdir, userInfo } from "node:os";
 import { basename, dirname, join } from "node:path";
 import { createRequire } from "node:module";
 import { fileURLToPath } from "node:url";
 import { createExternalProcessEnv } from "../server/paseo-env.js";
+import { writePrivateFileAtomicSync } from "../server/private-files.js";
 import type { TerminalCell, TerminalState } from "../shared/messages.js";
 
 const { Terminal } = xterm;
@@ -202,10 +203,13 @@ function prepareZshShellIntegrationRuntimeDir(sourceDir = resolveZshShellIntegra
   const runtimeDir = resolveZshShellIntegrationRuntimeDir();
   mkdirSync(runtimeDir, { recursive: true, mode: 0o700 });
   chmodSync(runtimeDir, 0o700);
-  copyFileSync(join(readableSourceDir, ".zshenv"), join(runtimeDir, ".zshenv"));
+  writePrivateFileAtomicSync(
-  copyFileSync(
+    join(runtimeDir, ".zshenv"),
-    join(readableSourceDir, "paseo-integration.zsh"),
+    readFileSync(join(readableSourceDir, ".zshenv")),
+  );
+  writePrivateFileAtomicSync(
     join(runtimeDir, "paseo-integration.zsh"),
+    readFileSync(join(readableSourceDir, "paseo-integration.zsh")),
   );
   return runtimeDir;
 }