server: handleConn's return error cannot be catched

[kayrus]

There there is no way to catch errors, returned by handleConn method:

go-smtp/server.go

Line 124 in 30169ac

go s.handleConn(newConn(c, s))

go-smtp/server.go

Line 128 in 30169ac

func (s *Server) handleConn(c *Conn) error {

[emersion]

How does net/http handle this?

[kayrus]

@emersion net/http's serve method doesn't return err, it passes it to the ErrorLog handler.

[emersion]

Hm, and ErrorLog seems to be used for many kinds of failures, both server-side panics, TLS handshakes and handler errors.

[kayrus]

BTW, I noticed more limitations in ErrorLog handler:

• it doesn't preserve the original err, it contains only the error text ("%v", err instead of the "%w", err).
• it doesn't preserve the TCP connection state c.State()

If I'd have a logging struct satisfying the ErrorLog interface, I'd like to have an ability to get the original error and the TCP connection state data.