net/http,x/net/http2: HTTP/2 RoundTrip does not close request body if ClientConnPool's GetClientConn fails

[alex-negret]

The RoundTrip contract states that the request body should be closed by RoundTrip, even when an error occurs.
https://pkg.go.dev/net/http#RoundTripper

The HTTP/2 RoundTrip / RoundTripOpt does not close the request body, if its client connection pool cannot acquire a connection (see transport.go#557).

[bcmills]

(attn @neild)

[bcmills]

@alex-negret, would you like to try contributing a fix? (I know net/http and x/net/http2 are pretty difficult to follow in general, but in this case it seems like the hardest part will be writing a regression test.)

[gopherbot]

Change https://go.dev/cl/508399 mentions this issue: net/http,x/net/http2: close request body in HTTP/2 RoundTrip if GetClientConn fails

[neganovalexey]

I've tried to fix this within HTTP/2-specific code. However, I had to make an exception from the rule in order not to break current net/http behavior.