Ivan Gabaldon

## 1. Environment ### 1a. Operating system and version ``` Linux 5.14.0-503.11.1.el9_5.x86_64 ``` ### 1b. Caddy version (run `caddy version` or paste commit SHA) ``` 238f1108e6600049d9041abc88db24526ee4f882 ``` ### 1c. Go...

I have built *(using go 1.23.2)* several builds to narrow the search and from commit https://github.com/caddyserver/caddy/commit/5b44d6cea87e91723e166eb30041d0ec79c29e66 onwards this issue starts to appear.

Freshly started Caddy and Firefox, the log has been captured by accessing the site *for the first time* showing the issue. Log: ```console {"qlog_format":"JSON-SEQ","qlog_version":"0.3","title":"quic-go qlog","configuration":{"code_version":"v0.48.1"},"trace":{"vantage_point":{"type":"server"},"common_fields":{"ODCID":"018a44fc2526d77aba042d46e2ff56","group_id":"018a44fc2526d77aba042d46e2ff56","reference_time":1730979028594.441,"time_format":"relative"}}} {"time":0.052898,"name":"recovery:congestion_state_updated","data":{"new":"slow_start"}} {"time":0.059069,"name":"transport:parameters_set","data":{"owner":"local","original_destination_connection_id":"018a44fc2526d77aba042d46e2ff56","stateless_reset_token":"4a25ee4d6ff2b45dfcd78532d26179e2","initial_source_connection_id":"f7f3f43a","disable_active_migration":true,"max_idle_timeout":30000,"max_udp_payload_size":1452,"ack_delay_exponent":3,"max_ack_delay":26,"active_connection_id_limit":4,"initial_max_data":786432,"initial_max_stream_data_bidi_local":524288,"initial_max_stream_data_bidi_remote":524288,"initial_max_stream_data_uni":524288,"initial_max_streams_bidi":100,"initial_max_streams_uni":100}} {"time":0.080719,"name":"security:key_updated","data":{"trigger":"tls","key_type":"client_initial_secret"}} {"time":0.08143,"name":"security:key_updated","data":{"trigger":"tls","key_type":"server_initial_secret"}} {"time":0.172408,"name":"transport:version_information","data":{"server_versions":["1","6b3343cf"],"chosen_version":"1"}}...

> Could you bisect which commit in quic-go (between v0.46.0 and v0.47.0) caused this behavior? @marten-seemann From commit https://github.com/quic-go/quic-go/commit/7c3544ca34bc4ea1dc6e37381f7b395bc9936aa5 onwards the issue manifests.

Um, looks like that section of code is not being executed because no log msg with the headers appears in the console and I have run the same tests as...

> Visit about:logging, select the HTTP/3 preset, choose a logfile as the destination and start the capture process. There are no relevant logs, at least on the client side. @marten-seemann...

@marten-seemann I noticed that since commit https://github.com/quic-go/quic-go/commit/7c3544ca34bc4ea1dc6e37381f7b395bc9936aa5, the request body is no longer nil on reverseproxy package. I've created a quick patch that *"fixes"* this specific issue in my case..:...

Yes, it's a small test to identify which part of the request was the problematic one; as previously if the client did not send a body via HTTP/3, it went...

@marten-seemann Sorry, I forgot mentioning that the body checks were performed only and just before the request goes into the Caddy `reverseproxy` round-trip, I do not know if this is...

> Is there any discrepancy between HTTP/3 and the standard library HTTP versions with regards to the `Content-Length` field, that leads to this error surfacing on HTTP/3, but not on...