From e7c8e50895bbd86ab77a8cece343c4c926bcafec Mon Sep 17 00:00:00 2001
From: barry3406 <duan3406@gmail.com>
Date: Thu, 9 Apr 2026 06:10:21 -0700
Subject: [PATCH] fix: move Keys read inside RLock in Context.Copy() to prevent
 data race

Copy() reads c.Keys before acquiring the read lock, then clones the
stale reference under the lock. If another goroutine calls Set()
between the read and the lock acquisition, the cKeys variable may
reference a map being concurrently modified.

This is particularly dangerous on the first Set() call where c.Keys
transitions from nil to a new map allocation.
---
 context.go | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/context.go b/context.go
index 5174033e..34a6e7ca 100644
--- a/context.go
+++ b/context.go
@@ -132,9 +132,8 @@ func (c *Context) Copy() *Context {
 	cp.handlers = nil
 	cp.fullPath = c.fullPath
 
-	cKeys := c.Keys
 	c.mu.RLock()
-	cp.Keys = maps.Clone(cKeys)
+	cp.Keys = maps.Clone(c.Keys)
 	c.mu.RUnlock()
 
 	cParams := c.Params