log: Remove `Debugln()` and related functions from `Logger` interface

Drop `Debugln()` and related functions. The only difference to the
`Debug()` family of functions is that they use `fmt.Sprintln()` to
format the log message, which guarantees that the arguments will be
separated by a space. This difference is non-obvious and also not
supported by the `slog` package.

The only user of this function is the Yamux log wrapper, which we adapt
accordingly.

2 files changed, 3 insertions, 6 deletions

diff --git a/internal/grpc/backchannel/backchannel.go b/internal/grpc/backchannel/backchannel.go
index 121aa480a..bcbc09c0e 100644
--- a/internal/grpc/backchannel/backchannel.go
+++ b/internal/grpc/backchannel/backchannel.go
@@ -29,6 +29,7 @@
 package backchannel
 
 import (
+	"fmt"
 	"net"
 	"sync"
 
@@ -49,7 +50,8 @@ func (l yamuxLogWrapper) Printf(format string, args ...any) {
 }
 
 func (l yamuxLogWrapper) Println(args ...any) {
-	l.logger.Infoln(args...)
+	msg := fmt.Sprintln(args...)
+	l.logger.Info(msg[:len(msg)-1])
 }
 
 // magicBytes are sent by the client to server to identify as a multiplexing aware client.
diff --git a/internal/log/logger.go b/internal/log/logger.go
index 4c8cf2e13..9f07ec205 100644
--- a/internal/log/logger.go
+++ b/internal/log/logger.go
@@ -28,11 +28,6 @@ type Logger interface {
 	Warn(args ...any)
 	Error(args ...any)
 
-	Debugln(args ...any)
-	Infoln(args ...any)
-	Warnln(args ...any)
-	Errorln(args ...any)
-
 	StreamServerInterceptor(...grpcmwlogrus.Option) grpc.StreamServerInterceptor
 	UnaryServerInterceptor(...grpcmwlogrus.Option) grpc.UnaryServerInterceptor
 }