From 67d0706ea44bab5472619ce8308c0a0b45c229bb Mon Sep 17 00:00:00 2001
From: yuhan6665 <1588741+yuhan6665@users.noreply.github.com>
Date: Sat, 12 Sep 2026 20:11:14 -0400
Subject: [PATCH] crypto/tls: make deleting a missing session cache key a no-op
 lruSessionCache.Put is documented to remove the entry for sessionKey when cs
 is nil, but it only did so if the key was already in the cache. Otherwise it
 inserted an entry with a nil state, evicting the least recently used entry if
 the cache was full.

Fixes #79861

Change-Id: Ie9abd6921a1a949f3fa796b63a235790fa42fb87
GitHub-Last-Rev: db2c9b9
GitHub-Pull-Request: #81042
Reviewed-on: https://go-review.googlesource.com/c/go/+/819960
Auto-Submit: Filippo Valsorda <filippo@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Filippo Valsorda <filippo@golang.org>
LUCI-TryBot-Result: golang-scoped@luci-project-accounts.iam.gserviceaccount.com <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
---
 common.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/common.go b/common.go
index efd4f6d..cdda38a 100644
--- a/common.go
+++ b/common.go
@@ -1770,6 +1770,10 @@ func (c *lruSessionCache) Put(sessionKey string, cs *ClientSessionState) {
 		return
 	}
 
+	if cs == nil {
+		return
+	}
+
 	if c.q.Len() < c.capacity {
 		entry := &lruSessionCacheEntry{sessionKey, cs}
 		c.m[sessionKey] = c.q.PushFront(entry)