From 71988d6719db20e1be24586bab201af72b021b3c Mon Sep 17 00:00:00 2001
From: David Rubin <david@vortan.dev>
Date: Thu, 6 Nov 2025 17:44:28 -0800
Subject: [PATCH] Io.net: set `receive{,Timeout}` message to `init`

If we use `undefined`, then `netReceive` can `@intCast` the
control slice len to msghdr controllen, which is sometimes `u32`,
even on 64-bit platforms.

`init` just avoids this entirely by setting `control` to an empty
slice rather than undefined.
---
 lib/std/Io/net.zig | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/std/Io/net.zig b/lib/std/Io/net.zig
index c051d004e2..ee1e93ced2 100644
--- a/lib/std/Io/net.zig
+++ b/lib/std/Io/net.zig
@@ -1118,7 +1118,7 @@ pub const Socket = struct {
     /// See also:
     /// * `receiveTimeout`
     pub fn receive(s: *const Socket, io: Io, buffer: []u8) ReceiveError!IncomingMessage {
-        var message: IncomingMessage = undefined;
+        var message: IncomingMessage = .init;
         const maybe_err, const count = io.vtable.netReceive(io.userdata, s.handle, (&message)[0..1], buffer, .{}, .none);
         if (maybe_err) |err| switch (err) {
             // No timeout is passed to `netReceieve`, so it must not return timeout related errors.
@@ -1144,7 +1144,7 @@ pub const Socket = struct {
         buffer: []u8,
         timeout: Io.Timeout,
     ) ReceiveTimeoutError!IncomingMessage {
-        var message: IncomingMessage = undefined;
+        var message: IncomingMessage = .init;
         const maybe_err, const count = io.vtable.netReceive(io.userdata, s.handle, (&message)[0..1], buffer, .{}, timeout);
         if (maybe_err) |err| return err;
         assert(1 == count);