Remove deprecated back-compat things

DiscardLogger became a LogSink, so leaving that as a type was only
needed for NullLogger.

NullLogger can be completely replaced with Discard().

InfoLogger is vestigial and since this is a breaking change anyway,
let's kill it off.

Not that Logger is a type, we do not need WithCallDepth() as a
standalone anymore.

discard.go

@@ -21,33 +21,33 @@ package logr
 func Discard() Logger {
 	return Logger{
 		level: 0,
-		sink:  DiscardLogger{},
+		sink:  discardLogger{},
 	}
 }
 
-// DiscardLogger is a LogSink that discards all messages.
-type DiscardLogger struct{}
+// discardLogger is a LogSink that discards all messages.
+type discardLogger struct{}
 
 // Verify that it actually implements the interface
-var _ LogSink = DiscardLogger{}
+var _ LogSink = discardLogger{}
 
-func (l DiscardLogger) Init(RuntimeInfo) {
+func (l discardLogger) Init(RuntimeInfo) {
 }
 
-func (l DiscardLogger) Enabled(int) bool {
+func (l discardLogger) Enabled(int) bool {
 	return false
 }
 
-func (l DiscardLogger) Info(int, string, ...interface{}) {
+func (l discardLogger) Info(int, string, ...interface{}) {
 }
 
-func (l DiscardLogger) Error(error, string, ...interface{}) {
+func (l discardLogger) Error(error, string, ...interface{}) {
 }
 
-func (l DiscardLogger) WithValues(...interface{}) LogSink {
+func (l discardLogger) WithValues(...interface{}) LogSink {
 	return l
 }
 
-func (l DiscardLogger) WithName(string) LogSink {
+func (l discardLogger) WithName(string) LogSink {
 	return l
 }

logr.go

@@ -273,14 +273,6 @@ func (l Logger) WithCallDepth(depth int) Logger {
 	return l
 }
 
-// InfoLogger provides compatibility with code that relies on the v0.1.0
-// interface.
-//
-// Deprecated: InfoLogger is an artifact of early versions of this API.  New
-// users should never use it and existing users should use Logger instead. This
-// will be removed in a future release.
-type InfoLogger = Logger
-
 // contextKey is how we find Loggers in a context.Context.
 type contextKey struct{}
 
@@ -384,22 +376,3 @@ type CallDepthLogSink interface {
 	// Successive calls to this are additive.
 	WithCallDepth(depth int) LogSink
 }
-
-// WithCallDepth returns a Logger that will offset the call stack by the
-// specified number of frames when logging call site information, if possible.
-// This is useful for users who have helper functions between the "real" call
-// site and the actual calls to Logger methods.  If depth is 0 the attribution
-// should be to the direct caller of this function.  If depth is 1 the
-// attribution should skip 1 call frame, and so on.  Successive calls to this
-// are additive.
-//
-// If the underlying log implementation supports a WithCallDepth(int) method,
-// it will be called and the result returned.  If the implementation does not
-// support CallDepthLogSink, the original Logger will be returned.
-//
-// Deprecated: WithCallDepth is an artifact of early versions of this API.  New
-// users should never use it and existing users should use Logger.WithCallDepth
-// instead. This will be removed in a future release.
-func WithCallDepth(logger Logger, depth int) Logger {
-	return logger.WithCallDepth(depth)
-}