From 36ea837736a07ad3a0ab8fe5735be124aa200202 Mon Sep 17 00:00:00 2001
From: Brad Fitzpatrick <bradfitz@tailscale.com>
Date: Thu, 16 Jun 2022 11:24:04 -0700
Subject: [PATCH] util/deephash: fix map hashing to actually hash elements

Fixes #4868

Change-Id: I574fd139cb7f7033dd93527344e6aa0e625477c7
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
---
 util/deephash/deephash.go      | 2 +-
 util/deephash/deephash_test.go | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/util/deephash/deephash.go b/util/deephash/deephash.go
index 23d910172..955f83e55 100644
--- a/util/deephash/deephash.go
+++ b/util/deephash/deephash.go
@@ -342,7 +342,7 @@ func (h *hasher) hashMap(v reflect.Value) {
 		e.SetIterValue(iter)
 		mh.h.reset()
 		mh.h.hashValue(k)
-		mh.h.hashValue(v)
+		mh.h.hashValue(e)
 		sum.xor(mh.h.sum())
 	}
 	h.bw.Write(append(h.scratch[:0], sum.sum[:]...)) // append into scratch to avoid heap allocation
diff --git a/util/deephash/deephash_test.go b/util/deephash/deephash_test.go
index bccebba62..3650beade 100644
--- a/util/deephash/deephash_test.go
+++ b/util/deephash/deephash_test.go
@@ -132,6 +132,15 @@ func TestDeepHash(t *testing.T) {
 	}
 }
 
+// Tests that we actually hash map elements. Whoops.
+func TestIssue4868(t *testing.T) {
+	m1 := map[int]string{1: "foo"}
+	m2 := map[int]string{1: "bar"}
+	if Hash(m1) == Hash(m2) {
+		t.Error("bogus")
+	}
+}
+
 func getVal() []any {
 	return []any{
 		&wgcfg.Config{