p2p: remove unnecessary panic handling in PEX reactor (tendermint#8110)

The message handling in this reactor is all under control of the reactor
itself, and does not call out to callbacks or other externally-supplied code.
It doesn't need to check for panics.

- Remove an irrelevant channel ID check.
- Remove an unnecessary panic recovery wrapper.

internal/p2p/pex/reactor.go

@@ -3,7 +3,6 @@ package pex
 import (
 	"context"
 	"fmt"
-	"runtime/debug"
 	"sync"
 	"time"
 
@@ -192,7 +191,7 @@ func (r *Reactor) processPexCh(ctx context.Context) {
 			}
 
 			// A request from another peer, or a response to one of our requests.
-			dur, err := r.handleMessage(ctx, r.pexCh.ID, envelope)
+			dur, err := r.handlePexMessage(ctx, envelope)
 			if err != nil {
 				r.logger.Error("failed to process message",
 					"ch_id", r.pexCh.ID, "envelope", envelope, "err", err)
@@ -287,28 +286,6 @@ func (r *Reactor) handlePexMessage(ctx context.Context, envelope *p2p.Envelope)
 	}
 }
 
-// handleMessage handles an Envelope sent from a peer on the specified Channel.
-// This method will convert a panic in message handling as an error.
-func (r *Reactor) handleMessage(ctx context.Context, chID p2p.ChannelID, envelope *p2p.Envelope) (_ time.Duration, err error) {
-	defer func() {
-		if e := recover(); e != nil {
-			err = fmt.Errorf("panic in processing message: %v", e)
-			r.logger.Error(
-				"recovering from processing message panic",
-				"err", err,
-				"stack", string(debug.Stack()),
-			)
-		}
-	}()
-
-	r.logger.Debug("received PEX message", "peer", envelope.From)
-
-	if chID == p2p.ChannelID(PexChannel) {
-		return r.handlePexMessage(ctx, envelope)
-	}
-	return 0, fmt.Errorf("unknown channel ID (%d) for envelope (%v)", chID, envelope)
-}
-
 // processPeerUpdate processes a PeerUpdate. For added peers, PeerStatusUp, we
 // send a request for addresses.
 func (r *Reactor) processPeerUpdate(peerUpdate p2p.PeerUpdate) {