From 61313d86e0d7d4e8872beb5889aefcf14b65cad9 Mon Sep 17 00:00:00 2001
From: Joe Andaverde <joe.andaverde@gmail.com>
Date: Wed, 23 Feb 2022 16:09:57 -0600
Subject: [PATCH] Set header content type instead of overwriting all headers
 (#14222)

* Set header content type instead of overwriting all headers

* Add changelog file
---
 api/logical.go      | 5 +----
 changelog/14222.txt | 3 +++
 2 files changed, 4 insertions(+), 4 deletions(-)
 create mode 100644 changelog/14222.txt

diff --git a/api/logical.go b/api/logical.go
index 68f3e9100..f7d2b4a40 100644
--- a/api/logical.go
+++ b/api/logical.go
@@ -5,7 +5,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"net/http"
 	"net/url"
 	"os"
 	"strings"
@@ -145,9 +144,7 @@ func (c *Logical) Write(path string, data map[string]interface{}) (*Secret, erro
 
 func (c *Logical) JSONMergePatch(ctx context.Context, path string, data map[string]interface{}) (*Secret, error) {
 	r := c.c.NewRequest("PATCH", "/v1/"+path)
-	r.Headers = http.Header{
-		"Content-Type": []string{"application/merge-patch+json"},
-	}
+	r.Headers.Set("Content-Type", "application/merge-patch+json")
 	if err := r.SetJSONBody(data); err != nil {
 		return nil, err
 	}
diff --git a/changelog/14222.txt b/changelog/14222.txt
new file mode 100644
index 000000000..3d9cfb10b
--- /dev/null
+++ b/changelog/14222.txt
@@ -0,0 +1,3 @@
+```release-note: bug
+core/api: Fix overwriting of request headers when using JSONMergePatch.
+```