From ff7ecb4efc2f754709ec018ae822fb411fcfa5a9 Mon Sep 17 00:00:00 2001
From: Basavaraj PB <basavarajbankolli76@gmail.com>
Date: Tue, 10 Mar 2026 23:28:14 +0530
Subject: [PATCH] os/exec: document that Cmd.Wait must not be called
 concurrently

Clarify in the Wait documentation that it must not be called
concurrently from multiple goroutines. Also note that a custom
Cmd.Cancel function should not call Wait because Cancel may be
invoked by watchCtx in a separate goroutine.

Fixes #78046

Change-Id: I5c0ebc41bd3c39c78f3b37539c59cdfedfd90e72
Reviewed-on: https://go-review.googlesource.com/c/go/+/753602
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Mark Freeman <markfreeman@google.com>
---
 src/os/exec/exec.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/os/exec/exec.go b/src/os/exec/exec.go
index e5bf97a188..26ddfe633c 100644
--- a/src/os/exec/exec.go
+++ b/src/os/exec/exec.go
@@ -929,6 +929,9 @@ func (e *ExitError) Error() string {
 // If any of c.Stdin, c.Stdout or c.Stderr are not an [*os.File], Wait also waits
 // for the respective I/O loop copying to or from the process to complete.
 //
+// Wait must not be called concurrently from multiple goroutines.
+// A custom Cmd.Cancel function should not call Wait.
+//
 // Wait releases any resources associated with the [Cmd].
 func (c *Cmd) Wait() error {
 	if c.Process == nil {