server: Don't recover from panics

gemini.go

@@ -21,12 +21,6 @@ var (
 	// methods after a call to Shutdown or Close.
 	ErrServerClosed = errors.New("gemini: server closed")
 
-	// ErrAbortHandler is a sentinel panic value to abort a handler.
-	// While any panic from ServeGemini aborts the response to the client,
-	// panicking with ErrAbortHandler also suppresses logging of a stack
-	// trace to the server's error log.
-	ErrAbortHandler = errors.New("gemini: abort Handler")
-
 	// ErrHandlerTimeout is returned on ResponseWriter Write calls
 	// in handlers which have timed out.
 	ErrHandlerTimeout = errors.New("gemini: Handler timeout")

handler.go

@@ -14,13 +14,6 @@ import (
 // of the ServeGemini call.
 //
 // Handlers should not modify the provided Request.
-//
-// If ServeGemini panics, the server (the caller of ServeGemini) assumes that
-// the effect of the panic was isolated to the active request. It recovers
-// the panic, logs a stack trace to the server error log, and closes the
-// network connection. To abort a handler so the client sees an interrupted
-// response but the server doesn't log an error, panic with the value
-// ErrAbortHandler.
 type Handler interface {
 	ServeGemini(context.Context, ResponseWriter, *Request)
 }

server.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"log"
 	"net"
-	"runtime"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -298,15 +297,6 @@ func (srv *Server) serveConn(ctx context.Context, conn net.Conn) {
 	defer srv.tryFinishShutdown()
 	defer srv.deleteConn(&conn)
 
-	defer func() {
-		if err := recover(); err != nil && err != ErrAbortHandler {
-			const size = 64 << 10
-			buf := make([]byte, size)
-			buf = buf[:runtime.Stack(buf, false)]
-			srv.logf("gemini: panic serving %v: %v\n%s", conn.RemoteAddr(), err, buf)
-		}
-	}()
-
 	if d := srv.ReadTimeout; d != 0 {
 		conn.SetReadDeadline(time.Now().Add(d))
 	}