forward IPC to child process if running package script (oven-sh#13934)

Co-authored-by: Jarred Sumner <[email protected]>

src/bun.js/api/bun/process.zig

@@ -962,6 +962,7 @@ pub const PosixSpawnOptions = struct {
     stdin: Stdio = .ignore,
     stdout: Stdio = .ignore,
     stderr: Stdio = .ignore,
+    ipc: ?bun.FileDescriptor = null,
     extra_fds: []const Stdio = &.{},
     cwd: []const u8 = "",
     detached: bool = false,
@@ -1031,6 +1032,7 @@ pub const WindowsSpawnOptions = struct {
     stdin: Stdio = .ignore,
     stdout: Stdio = .ignore,
     stderr: Stdio = .ignore,
+    ipc: ?bun.FileDescriptor = null,
     extra_fds: []const Stdio = &.{},
     cwd: []const u8 = "",
     detached: bool = false,
@@ -1077,6 +1079,7 @@ pub const PosixSpawnResult = struct {
     stdin: ?bun.FileDescriptor = null,
     stdout: ?bun.FileDescriptor = null,
     stderr: ?bun.FileDescriptor = null,
+    ipc: ?bun.FileDescriptor = null,
     extra_pipes: std.ArrayList(bun.FileDescriptor) = std.ArrayList(bun.FileDescriptor).init(bun.default_allocator),
 
     memfds: [3]bool = .{ false, false, false },
@@ -1260,6 +1263,11 @@ pub fn spawnProcessPosix(
     attr.set(@intCast(flags)) catch {};
     attr.resetSignals() catch {};
 
+    if (options.ipc) |ipc| {
+        try actions.inherit(ipc);
+        spawned.ipc = ipc;
+    }
+
     const stdio_options: [3]PosixSpawnOptions.Stdio = .{ options.stdin, options.stdout, options.stderr };
     const stdios: [3]*?bun.FileDescriptor = .{ &spawned.stdin, &spawned.stdout, &spawned.stderr };
 
@@ -1765,6 +1773,7 @@ pub const sync = struct {
         stdin: Stdio = .ignore,
         stdout: Stdio = .inherit,
         stderr: Stdio = .inherit,
+        ipc: ?bun.FileDescriptor = null,
         cwd: []const u8 = "",
         detached: bool = false,
 
@@ -1799,6 +1808,8 @@ pub const sync = struct {
                 .stdin = this.stdin.toStdio(),
                 .stdout = this.stdout.toStdio(),
                 .stderr = this.stderr.toStdio(),
+                .ipc = this.ipc,
+
                 .cwd = this.cwd,
                 .detached = this.detached,
                 .use_execve_on_macos = this.use_execve_on_macos,

src/cli/run_command.zig

@@ -341,6 +341,12 @@ pub const RunCommand = struct {
             combined_script,
         };
 
+        const ipc_fd = if (!Environment.isWindows) blk: {
+            const node_ipc_fd = bun.getenvZ("NODE_CHANNEL_FD") orelse break :blk null;
+            const fd = std.fmt.parseInt(u32, node_ipc_fd, 10) catch break :blk null;
+            break :blk bun.toFD(@as(i32, @intCast(fd)));
+        } else null; // TODO: implement on Windows
+
         const spawn_result = switch ((bun.spawnSync(&.{
             .argv = &argv,
             .argv0 = shell_bin.ptr,
@@ -353,6 +359,7 @@ pub const RunCommand = struct {
             .stderr = .inherit,
             .stdout = .inherit,
             .stdin = .inherit,
+            .ipc = ipc_fd,
 
             .windows = if (Environment.isWindows) .{
                 .loop = JSC.EventLoopHandle.init(JSC.MiniEventLoop.initGlobal(env)),

test/js/bun/spawn/bun-ipc-inherit.test.ts

@@ -0,0 +1,28 @@
+import { spawn, spawnSync, env } from "bun";
+import fs from "node:fs/promises";
+import { describe, expect, it } from "bun:test";
+import { bunExe, isWindows } from "harness";
+import path from "path";
+
+it.todoIf(isWindows)("spawning a bun package script should inherit the ipc fd", async () => {
+  await fs.writeFile(
+    path.join(process.cwd(), "package.json"),
+    JSON.stringify({
+      scripts: {
+        test: `${bunExe()} -e 'process.send("hello")'`,
+      },
+    }),
+  );
+
+  let testMessage;
+
+  const child = spawn([bunExe(), "run", "test"], {
+    ipc: message => {
+      testMessage = message;
+    },
+    stdio: ["inherit", "inherit", "inherit"],
+  });
+
+  await child.exited;
+  expect(testMessage).toBe("hello");
+});