From 50b3ce86305cf3655d5956c4896efcf8c2713671 Mon Sep 17 00:00:00 2001
From: Beth Griggs <bgriggs@redhat.com>
Date: Thu, 4 Mar 2021 17:17:47 +0000
Subject: [PATCH] http: runtime deprecate legacy HTTP parser

The legacy HTTP parser, used by default in versions of Node.js prior to
12.0.0, is deprecated. The legacy HTTP parser cannot be guaranteed to be
supported after April 2021. This commit introduces a deprecation warning
for the legacy HTTP parser.
---
 doc/api/deprecations.md                              |  5 ++++-
 src/node_http_parser_impl.h                          |  7 +++++++
 test/parallel/test-http-parser-legacy-deprecation.js | 11 +++++++++++
 3 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 test/parallel/test-http-parser-legacy-deprecation.js

diff --git a/doc/api/deprecations.md b/doc/api/deprecations.md
index 8333597513a756..82226d4fbe4772 100644
--- a/doc/api/deprecations.md
+++ b/doc/api/deprecations.md
@@ -2469,12 +2469,15 @@ Module.createRequireFromPath() is deprecated. Please use [`module.createRequire(
 ### DEP0131: Legacy HTTP parser
 <!-- YAML
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/TBD
+    description: Runtime deprecation.
   - version: v12.3.0
     pr-url: https://github.com/nodejs/node/pull/27498
     description: Documentation-only.
 -->
 
-Type: Documentation-only
+Type: Runtime
 
 The legacy HTTP parser, used by default in versions of Node.js prior to 12.0.0,
 is deprecated. This deprecation applies to users of the
diff --git a/src/node_http_parser_impl.h b/src/node_http_parser_impl.h
index 7c39bc15c72a38..77d09a939cb72b 100644
--- a/src/node_http_parser_impl.h
+++ b/src/node_http_parser_impl.h
@@ -26,6 +26,9 @@
 
 #include "node.h"
 #include "node_buffer.h"
+#ifndef NODE_EXPERIMENTAL_HTTP
+#include "node_process.h"
+#endif  /* NODE_EXPERIMENTAL_HTTP */
 #include "util.h"
 
 #include "async_wrap-inl.h"
@@ -1021,6 +1024,10 @@ void InitializeHttpParser(Local<Object> target,
 #ifndef NODE_EXPERIMENTAL_HTTP
   static uv_once_t init_once = UV_ONCE_INIT;
   uv_once(&init_once, InitMaxHttpHeaderSizeOnce);
+  ProcessEmitDeprecationWarning(
+    env,
+    "The legacy HTTP parser is deprecated.",
+    "DEP0131").IsNothing();
 #endif  /* NODE_EXPERIMENTAL_HTTP */
 }
 
diff --git a/test/parallel/test-http-parser-legacy-deprecation.js b/test/parallel/test-http-parser-legacy-deprecation.js
new file mode 100644
index 00000000000000..6c4c690a9b9169
--- /dev/null
+++ b/test/parallel/test-http-parser-legacy-deprecation.js
@@ -0,0 +1,11 @@
+'use strict';
+const common = require('../common');
+
+// Flags: --http-parser=legacy
+require('http');
+
+common.expectWarning({
+  DeprecationWarning:
+    ['The legacy HTTP parser is deprecated.',
+     'DEP0131']
+});