From 74baa065be123d57a1aaad1d7dff8b7c7fabbd8a Mon Sep 17 00:00:00 2001
From: Martin Ek <ek@increase.com>
Date: Sat, 26 Sep 2026 20:59:13 -0700
Subject: [PATCH] Cancel HTTP/2 streams when requests are interrupted

---
 lib/async/http/protocol/http2/client.rb       |  8 ++++
 .../protocol/http2/request_cancellation.rb    | 41 +++++++++++++++++++
 2 files changed, 49 insertions(+)
 create mode 100644 test/async/http/protocol/http2/request_cancellation.rb

diff --git a/lib/async/http/protocol/http2/client.rb b/lib/async/http/protocol/http2/client.rb
index bf1ca4a8..6e359a02 100644
--- a/lib/async/http/protocol/http2/client.rb
+++ b/lib/async/http/protocol/http2/client.rb
@@ -42,10 +42,18 @@ def call(request)
 						raise ::Protocol::HTTP::RefusedError, "Connection closed!" if self.closed?
 						
 						response = create_response
+						completed = false
+						
 						write_request(response, request)
 						read_response(response)
+						completed = true
 						
 						return response
+					ensure
+						# Cancel abandoned requests, including when the task is stopped while waiting for headers.
+						if response && !completed && !self.closed? && response.stream.active?
+							response.stream.send_reset_stream(::Protocol::HTTP2::Error::CANCEL)
+						end
 					end
 					
 					# Write a request to the remote server via the given response stream.
diff --git a/test/async/http/protocol/http2/request_cancellation.rb b/test/async/http/protocol/http2/request_cancellation.rb
new file mode 100644
index 00000000..122f68e4
--- /dev/null
+++ b/test/async/http/protocol/http2/request_cancellation.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+# Released under the MIT License.
+# Copyright, 2026, by Samuel Williams.
+
+require "async/http/protocol/http2"
+require "sus/fixtures/async/http"
+
+describe Async::HTTP::Protocol::HTTP2 do
+	include Sus::Fixtures::Async::HTTP::ServerContext
+	
+	let(:protocol) {subject}
+	
+	let(:app) do
+		Protocol::HTTP::Middleware.for do |request|
+			Async::Task.current.sleep(10) if request.path == "/slow"
+			
+			Protocol::HTTP::Response[200, {}, ["OK"]]
+		end
+	end
+	
+	it "cancels a timed-out request and reuses the connection" do
+		connection = Async::HTTP::Protocol::HTTP2.client(client_endpoint.connect)
+		task = Async::Task.current
+		
+		expect do
+			task.with_timeout(0.1) do
+				connection.call(Protocol::HTTP::Request["GET", "/slow", scheme: "http", authority: "localhost"])
+			end
+		end.to raise_exception(Async::TimeoutError)
+		
+		expect(connection.streams).to be(:empty?)
+		
+		response = connection.call(Protocol::HTTP::Request["GET", "/fast", scheme: "http", authority: "localhost"])
+		expect(response).to be(:success?)
+		expect(response.read).to be == "OK"
+	ensure
+		response&.close
+		connection&.close
+	end
+end