Ignore connection errors in read_line?.

lib/protocol/http1/connection.rb

@@ -349,7 +349,7 @@ def read(length)
 
 			# Read a line from the connection.
 			#
-			# @returns [String | Nil] the line read, or nil if the connection is gracefully closed.
+			# @returns [String | Nil] the line read, or nil if the connection is closed.
 			# @raises [LineLengthError] if the line is too long.
 			# @raises [ProtocolError] if the line is not terminated properly.
 			def read_line?
@@ -366,8 +366,9 @@ def read_line?
 				end
 
 				return line
-
-				# I considered rescuing Errno::ECONNRESET here, but it seems like that would be ignoring a potentially serious error.
+			# If a connection is shut down abruptly, we treat it as EOF, but only specifically in `read_line?`.
+			rescue Errno::ECONNRESET
+				return nil
 			end
 
 			# Read a line from the connection.

releases.md

@@ -3,6 +3,7 @@
 ## Unreleased
 
   - Tidy up implementation of `read_line?` to handle line length errors and protocol violations more clearly.
+  - Improve error handling for unexpected connection closures (`Errno::ECONNRESET`) in `read_line?`.
 
 ## v0.35.0
 

test/protocol/http1/connection.rb

@@ -48,6 +48,12 @@
 				server.read_line?
 			end.to raise_exception(Protocol::HTTP1::ProtocolError)
 		end
+
+		it "returns nil on Errno::ECONNRESET" do
+			expect(server.stream).to receive(:gets).and_raise(Errno::ECONNRESET)
+
+			expect(server.read_line?).to be_nil
+		end
 	end
 
 	with "#read_request" do