Jarred-Sumner The big caveat for the workaround proposed for posix_spawn_file_actions_addchdir_np on macOS 10.x is that the cwd option for the following calls cannot be overridden and will incorrectly use the current working directory of the calling process:

child_process.exec
child_process.execSync
child_process.spawn
child_process.spawnSync
child_process.execFile
child_process.execFileSync

as they're all based on Bun.spawn which calls:

bun/src/bun.js/api/bun/subprocess.zig

Line 1231 in 451ccfd

actions.chdir(cwd) catch |err| return globalThis.handleError(err, "in chdir()");

which in turn calls:

bun/src/bun.js/api/bun/spawn.zig

Lines 153 to 159 in 451ccfd

	pub fn chdir(self: *Actions, path: []const u8) !void {
	const posix_path = try toPosixPath(path);
	return self.chdirZ(&posix_path);
	}
	pub fn chdirZ(self: *Actions, path: [*:0]const u8) !void {
	switch (errno(system.posix_spawn_file_actions_addchdir_np(&self.actions, path))) {

Until a proper fix is made for macos 10.x, an assert could be added to terminate the program if the cwd option is specified and does not match the normalized getcwd().

When I proposed the original workaround I thought it was an unimportant start-up instruction.

Originally posted by @kzc in #1266 (comment)

We should at least add the aforementioned assert and terminate with error message explaining the current issue with MacOS 10.x