From d6d764bcc970e1e50486153588eda8a92cf5b5e4 Mon Sep 17 00:00:00 2001
From: Zanie <contact@zanie.dev>
Date: Wed, 20 Dec 2023 20:44:39 -0600
Subject: [PATCH] Avoid closing connections when `HEAD` requests have a content
 length

---
 src/waitress/task.py | 15 ++++++++-------
 tests/test_task.py   |  4 ++--
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/waitress/task.py b/src/waitress/task.py
index 956c0c0f..42cc6581 100644
--- a/src/waitress/task.py
+++ b/src/waitress/task.py
@@ -474,17 +474,18 @@ def start_response(status, headers, exc_info=None):
 
             cl = self.content_length
             if cl is not None:
-                if self.content_bytes_written != cl:
+                if self.content_bytes_written != cl and self.request.command != "HEAD":
                     # close the connection so the client isn't sitting around
                     # waiting for more data when there are too few bytes
                     # to service content-length
+                    # unless it's a HEAD request in which case we don't expect
+                    # to return any bytes regardless of the content length
                     self.close_on_finish = True
-                    if self.request.command != "HEAD":
-                        self.logger.warning(
-                            "application returned too few bytes (%s) "
-                            "for specified Content-Length (%s) via app_iter"
-                            % (self.content_bytes_written, cl),
-                        )
+                    self.logger.warning(
+                        "application returned too few bytes (%s) "
+                        "for specified Content-Length (%s) via app_iter"
+                        % (self.content_bytes_written, cl),
+                    )
         finally:
             if can_close_app_iter and hasattr(app_iter, "close"):
                 app_iter.close()
diff --git a/tests/test_task.py b/tests/test_task.py
index 47868e15..c7cb6f68 100644
--- a/tests/test_task.py
+++ b/tests/test_task.py
@@ -590,7 +590,7 @@ def app(environ, start_response):
         self.assertEqual(inst.close_on_finish, True)
         self.assertEqual(len(inst.logger.logged), 1)
 
-    def test_execute_app_do_not_warn_on_head(self):
+    def test_execute_app_head_with_content_length(self):
         def app(environ, start_response):
             start_response("200 OK", [("Content-Length", "3")])
             return [b""]
@@ -600,7 +600,7 @@ def app(environ, start_response):
         inst.channel.server.application = app
         inst.logger = DummyLogger()
         inst.execute()
-        self.assertEqual(inst.close_on_finish, True)
+        self.assertEqual(inst.close_on_finish, False)
         self.assertEqual(len(inst.logger.logged), 0)
 
     def test_execute_app_without_body_204_logged(self):