Respond with 414 when a line exceeds the maximum line length

[trevorturk]

Fixes #237.

Previously, when a request line or header line exceeded maximum_line_length, LineLengthError propagated past next_request (it doesn't include the BadRequest marker), so the server closed the connection without writing anything and the peer saw an unexplained EOF.

This PR rescues LineLengthError in next_request and uses the existing fail_request path to respond with 414 before re-raising, matching the existing BadRequest → 400 handling. The request-line and header-line cases can't be distinguished at the rescue site, so both get 414 as the more common case — happy to split the error by phase in protocol-http1 and map 414/431 instead if you'd prefer that precision.

Types of Changes

• Bug fix.

Contribution

• I added tests for my changes.
• I tested my changes locally.
• I agree to the Developer's Certificate of Origin 1.1.

[Copilot]

Pull request overview

This PR improves HTTP/1 server behavior when an incoming request line or header line exceeds maximum_line_length, ensuring the peer receives a proper HTTP response (414) instead of an unexplained EOF caused by LineLengthError escaping next_request.

Changes:

• Rescue Protocol::HTTP1::LineLengthError in Async::HTTP::Protocol::HTTP1::Server#next_request and send a 414 via fail_request before re-raising.
• Add HTTP/1.1 server specs asserting 414 for over-long request lines and header lines.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
lib/async/http/protocol/http1/server.rb	Catch LineLengthError during request parsing and write a 414 response before re-raising to avoid silent connection close.
test/async/http/protocol/http11.rb	Add regression tests for 414 responses when request line or header lines exceed the configured maximum length.

[ioquatix]

See feedback.

[trevorturk]

Good idea, updated, force pushed back into a single commit.