Raise EOFError when the connection closes while a write waits

lib/protocol/http2/connection.rb

@@ -298,28 +298,25 @@ def receive_goaway(frame)
 
 			# Write a single frame to the connection.
 			# @parameter frame [Frame] The frame to write.
+			# @raises [EOFError] If the connection is closed.
 			def write_frame(frame)
 				synchronize do
-					@framer.write_frame(frame)
+					open_framer.write_frame(frame)
 				end
 
-				@framer.flush
+				open_framer.flush
 			end
 
 			# Write multiple frames within a synchronized block.
 			# @yields {|framer| ...} The framer for writing multiple frames.
 			#   @parameter framer [Framer] The framer instance.
 			# @raises [EOFError] If the connection is closed.
 			def write_frames
-				if @framer
-					synchronize do
-						yield @framer
-					end
-
-					@framer.flush
-				else
-					raise EOFError, "Connection closed!"
+				synchronize do
+					yield open_framer
 				end
+
+				open_framer.flush
 			end
 
 			# Update local settings and adjust stream window capacities.
@@ -668,6 +665,13 @@ def receive_continuation(frame)
 			def receive_frame(frame)
 				# ignore.
 			end
+
+			private
+
+			# The connection is closed, and `@framer` cleared, by the task reading frames, which can happen while a writer waits for the lock or for the socket, so it is checked again at each use.
+			def open_framer
+				@framer or raise EOFError, "Connection closed!"
+			end
 		end
 	end
 end

releases.md

@@ -1,5 +1,9 @@
 # Releases
 
+## Unreleased
+
+  - `Connection#write_frame` and `#write_frames` raise `EOFError` when the connection closes while the write waits for the lock or the socket, rather than `NoMethodError` on the cleared framer.
+
 ## v0.29.1
 
   - Sign releases with the Socketry release certificate.

test/protocol/http2/connection.rb

@@ -104,6 +104,30 @@
 		end.to raise_exception(EOFError, message: be =~ /Connection closed/)
 	end
 
+	with "a connection which closes while a write waits for the lock" do
+		def before
+			super
+
+			def connection.synchronize
+				close
+				super
+			end
+		end
+
+		it "can't write a frame" do
+			expect do
+				connection.write_frame(Protocol::HTTP2::PingFrame.new)
+			end.to raise_exception(EOFError, message: be =~ /Connection closed/)
+		end
+
+		it "can't write frames" do
+			expect do
+				connection.write_frames do |framer|
+				end
+			end.to raise_exception(EOFError, message: be =~ /Connection closed/)
+		end
+	end
+
 	with "#close" do
 		it "closes the connection without active streams" do
 			# No active streams