http: deprecate writeHeader

doc/api/deprecations.md

@@ -1480,12 +1480,15 @@ instead.
 
 <!-- YAML
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/59060
+    description: Runtime deprecation.
   - version: v8.0.0
     pr-url: https://github.com/nodejs/node/pull/11355
     description: Documentation-only deprecation.
 -->
 
-Type: Documentation-only
+Type: Runtime
 
 The `node:http` module `ServerResponse.prototype.writeHeader()` API is
 deprecated. Please use `ServerResponse.prototype.writeHead()` instead.

lib/_http_server.js

@@ -81,6 +81,7 @@ const {
 } = require('internal/errors');
 const {
   assignFunctionName,
+  deprecate,
   kEmptyObject,
   promisify,
 } = require('internal/util');
@@ -439,8 +440,9 @@ function writeHead(statusCode, reason, obj) {
   return this;
 }
 
-// Docs-only deprecated: DEP0063
-ServerResponse.prototype.writeHeader = ServerResponse.prototype.writeHead;
+ServerResponse.prototype.writeHeader = deprecate(ServerResponse.prototype.writeHead,
+                                                 'ServerResponse.prototype.writeHeader is deprecated.',
+                                                 'DEP0063');
 
 function storeHTTPOptions(options) {
   this[kIncomingMessage] = options.IncomingMessage || IncomingMessage;

test/parallel/test-write-header.js

@@ -0,0 +1,20 @@
+'use strict';
+const common = require('../common');
+const assert = require('assert');
+const http = require('http');
+
+common.expectWarning('DeprecationWarning',
+                     'ServerResponse.prototype.writeHeader is deprecated.', 'DEP0063');
+
+const server = http.createServer(common.mustCall((req, res) => {
+  res.writeHeader(200, [ 'test', '2', 'test2', '2' ]);
+  res.end();
+})).listen(0, common.mustCall(() => {
+  http.get({ port: server.address().port }, common.mustCall((res) => {
+    assert.strictEqual(res.headers.test, '2');
+    assert.strictEqual(res.headers.test2, '2');
+    res.resume().on('end', common.mustCall(() => {
+      server.close();
+    }));
+  }));
+}));