From 069f9d96d179becc61231d566c9a75f1ec26e991 Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <iant@golang.org>
Date: Fri, 11 Dec 2020 19:10:00 -0800
Subject: [release-branch.go1.15] doc/go1.15: mention 1.15.3 cgo restriction on
 empty structs

For #40954

Change-Id: I6a30aed31a16e820817f4ca5c7f591222e922946
Reviewed-on: https://go-review.googlesource.com/c/go/+/277432
Trust: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
(cherry picked from commit 129bb1917b4914f0743ec9b4ef0dfb74df39c07d)
Reviewed-on: https://go-review.googlesource.com/c/go/+/278573
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
---
 doc/go1.15.html | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/doc/go1.15.html b/doc/go1.15.html
index c691bf3bd5..c9997c0ca3 100644
--- a/doc/go1.15.html
+++ b/doc/go1.15.html
@@ -397,6 +397,19 @@ Do not send CLs removing the interior tags from such phrases.
   documentation</a> for more information.
 </p>
 
+<p><!-- CL 250940 -->
+  In Go 1.15.3 and later, cgo will not permit Go code to allocate an
+  undefined struct type (a C struct defined as just <code>struct
+  S;</code> or similar) on the stack or heap.
+  Go code will only be permitted to use pointers to those types.
+  Allocating an instance of such a struct and passing a pointer, or a
+  full struct value, to C code was always unsafe and unlikely to work
+  correctly; it is now forbidden.
+  The fix is to either rewrite the Go code to use only pointers, or to
+  ensure that the Go code sees the full definition of the struct by
+  including the appropriate C header file.
+</p>
+
 <h3 id="commonname">X.509 CommonName deprecation</h3>
 
 <p><!-- CL 231379 -->
-- 
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