remove panic, and revert connserver from using non-blocking drainchannel safe (#2049)

Author: sawka

cmd/wsh/cmd/wshcmd-connserver.go

@@ -21,7 +21,6 @@ import (
 	"github.com/wavetermdev/waveterm/pkg/remote/fileshare/wshfs"
 	"github.com/wavetermdev/waveterm/pkg/util/packetparser"
 	"github.com/wavetermdev/waveterm/pkg/util/sigutil"
-	"github.com/wavetermdev/waveterm/pkg/util/utilfn"
 	"github.com/wavetermdev/waveterm/pkg/wavebase"
 	"github.com/wavetermdev/waveterm/pkg/wshrpc"
 	"github.com/wavetermdev/waveterm/pkg/wshrpc/wshclient"
@@ -163,7 +162,9 @@ func serverRunRouter(jwtToken string) error {
 		// just ignore and drain the rawCh (stdin)
 		// when stdin is closed, shutdown
 		defer wshutil.DoShutdown("", 0, true)
-		utilfn.DrainChannelSafe(rawCh, "serverRunRouter:stdin")
+		for range rawCh {
+			// ignore
+		}
 	}()
 	go func() {
 		for msg := range termProxy.FromRemoteCh {

pkg/util/utilfn/utilfn.go

@@ -1057,15 +1057,16 @@ func GracefulClose(closer io.Closer, debugName, closerName string) bool {
 }
 
 // DrainChannelSafe will drain a channel until it is empty or until a timeout is reached.
-// WARNING: This function will panic if the channel is not drained within the timeout.
 func DrainChannelSafe[T any](ch <-chan T, debugName string) {
 	drainTimeoutCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 	go func() {
 		defer cancel()
+	outer:
 		for {
 			select {
 			case <-drainTimeoutCtx.Done():
-				panic(debugName + ": timeout draining channel")
+				log.Printf("[error] timeout draining channel: %s\n", debugName)
+				break outer
 			case _, ok := <-ch:
 				if !ok {
 					return