rebase: bump k8s.io/klog/v2 from 2.30.0 to 2.40.1

Bumps [k8s.io/klog/v2](https://github.com/kubernetes/klog) from 2.30.0 to 2.40.1.
- [Release notes](https://github.com/kubernetes/klog/releases)
- [Changelog](https://github.com/kubernetes/klog/blob/main/RELEASE.md)
- [Commits](https://github.com/kubernetes/klog/compare/v2.30.0...v2.40.1)

---
updated-dependencies:
- dependency-name: k8s.io/klog/v2
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/k8s.io/klog/v2/klog.go

@@ -801,14 +801,19 @@ func (l *loggingT) infoS(logger *logr.Logger, filter LogFilter, depth int, msg s
 // printS is called from infoS and errorS if loggr is not specified.
 // set log severity by s
 func (l *loggingT) printS(err error, s severity, depth int, msg string, keysAndValues ...interface{}) {
-	b := &bytes.Buffer{}
-	b.WriteString(fmt.Sprintf("%q", msg))
+	// Only create a new buffer if we don't have one cached.
+	b := l.getBuffer()
+	// The message is always quoted, even if it contains line breaks.
+	// If developers want multi-line output, they should use a small, fixed
+	// message and put the multi-line output into a value.
+	b.WriteString(strconv.Quote(msg))
 	if err != nil {
-		b.WriteByte(' ')
-		b.WriteString(fmt.Sprintf("err=%q", err.Error()))
+		kvListFormat(&b.Buffer, "err", err)
 	}
-	kvListFormat(b, keysAndValues...)
-	l.printDepth(s, logging.logr, nil, depth+1, b)
+	kvListFormat(&b.Buffer, keysAndValues...)
+	l.printDepth(s, logging.logr, nil, depth+1, &b.Buffer)
+	// Make the buffer available for reuse.
+	l.putBuffer(b)
 }
 
 const missingValue = "(MISSING)"
@@ -823,19 +828,106 @@ func kvListFormat(b *bytes.Buffer, keysAndValues ...interface{}) {
 			v = missingValue
 		}
 		b.WriteByte(' ')
-
-		switch v.(type) {
-		case string, error:
-			b.WriteString(fmt.Sprintf("%s=%q", k, v))
-		case []byte:
-			b.WriteString(fmt.Sprintf("%s=%+q", k, v))
-		default:
-			if _, ok := v.(fmt.Stringer); ok {
-				b.WriteString(fmt.Sprintf("%s=%q", k, v))
-			} else {
-				b.WriteString(fmt.Sprintf("%s=%+v", k, v))
-			}
+		// Keys are assumed to be well-formed according to
+		// https://github.com/kubernetes/community/blob/master/contributors/devel/sig-instrumentation/migration-to-structured-logging.md#name-arguments
+		// for the sake of performance. Keys with spaces,
+		// special characters, etc. will break parsing.
+		if k, ok := k.(string); ok {
+			// Avoid one allocation when the key is a string, which
+			// normally it should be.
+			b.WriteString(k)
+		} else {
+			b.WriteString(fmt.Sprintf("%s", k))
 		}
+
+		// The type checks are sorted so that more frequently used ones
+		// come first because that is then faster in the common
+		// cases. In Kubernetes, ObjectRef (a Stringer) is more common
+		// than plain strings
+		// (https://github.com/kubernetes/kubernetes/pull/106594#issuecomment-975526235).
+		switch v := v.(type) {
+		case fmt.Stringer:
+			writeStringValue(b, true, stringerToString(v))
+		case string:
+			writeStringValue(b, true, v)
+		case error:
+			writeStringValue(b, true, v.Error())
+		case []byte:
+			// In https://github.com/kubernetes/klog/pull/237 it was decided
+			// to format byte slices with "%+q". The advantages of that are:
+			// - readable output if the bytes happen to be printable
+			// - non-printable bytes get represented as unicode escape
+			//   sequences (\uxxxx)
+			//
+			// The downsides are that we cannot use the faster
+			// strconv.Quote here and that multi-line output is not
+			// supported. If developers know that a byte array is
+			// printable and they want multi-line output, they can
+			// convert the value to string before logging it.
+			b.WriteByte('=')
+			b.WriteString(fmt.Sprintf("%+q", v))
+		default:
+			writeStringValue(b, false, fmt.Sprintf("%+v", v))
+		}
+	}
+}
+
+func stringerToString(s fmt.Stringer) (ret string) {
+	defer func() {
+		if err := recover(); err != nil {
+			ret = "nil"
+		}
+	}()
+	ret = s.String()
+	return
+}
+
+func writeStringValue(b *bytes.Buffer, quote bool, v string) {
+	data := []byte(v)
+	index := bytes.IndexByte(data, '\n')
+	if index == -1 {
+		b.WriteByte('=')
+		if quote {
+			// Simple string, quote quotation marks and non-printable characters.
+			b.WriteString(strconv.Quote(v))
+			return
+		}
+		// Non-string with no line breaks.
+		b.WriteString(v)
+		return
+	}
+
+	// Complex multi-line string, show as-is with indention like this:
+	// I... "hello world" key=<
+	// <tab>line 1
+	// <tab>line 2
+	//  >
+	//
+	// Tabs indent the lines of the value while the end of string delimiter
+	// is indented with a space. That has two purposes:
+	// - visual difference between the two for a human reader because indention
+	//   will be different
+	// - no ambiguity when some value line starts with the end delimiter
+	//
+	// One downside is that the output cannot distinguish between strings that
+	// end with a line break and those that don't because the end delimiter
+	// will always be on the next line.
+	b.WriteString("=<\n")
+	for index != -1 {
+		b.WriteByte('\t')
+		b.Write(data[0 : index+1])
+		data = data[index+1:]
+		index = bytes.IndexByte(data, '\n')
+	}
+	if len(data) == 0 {
+		// String ended with line break, don't add another.
+		b.WriteString(" >")
+	} else {
+		// No line break at end of last line, write rest of string and
+		// add one.
+		b.WriteByte('\t')
+		b.Write(data)
+		b.WriteString("\n >")
 	}
 }
 
@@ -917,7 +1009,15 @@ func LogToStderr(stderr bool) {
 
 // output writes the data to the log files and releases the buffer.
 func (l *loggingT) output(s severity, log *logr.Logger, buf *buffer, depth int, file string, line int, alsoToStderr bool) {
+	var isLocked = true
 	l.mu.Lock()
+	defer func() {
+		if isLocked {
+			// Unlock before returning in case that it wasn't done already.
+			l.mu.Unlock()
+		}
+	}()
+
 	if l.traceLocation.isSet() {
 		if l.traceLocation.match(file, line) {
 			buf.Write(stacks(false))
@@ -980,6 +1080,7 @@ func (l *loggingT) output(s severity, log *logr.Logger, buf *buffer, depth int,
 		// If we got here via Exit rather than Fatal, print no stacks.
 		if atomic.LoadUint32(&fatalNoStacks) > 0 {
 			l.mu.Unlock()
+			isLocked = false
 			timeoutFlush(10 * time.Second)
 			os.Exit(1)
 		}
@@ -997,11 +1098,12 @@ func (l *loggingT) output(s severity, log *logr.Logger, buf *buffer, depth int,
 			}
 		}
 		l.mu.Unlock()
+		isLocked = false
 		timeoutFlush(10 * time.Second)
-		os.Exit(255) // C++ uses -1, which is silly because it's anded with 255 anyway.
+		os.Exit(255) // C++ uses -1, which is silly because it's anded(&) with 255 anyway.
 	}
 	l.putBuffer(buf)
-	l.mu.Unlock()
+
 	if stats := severityStats[s]; stats != nil {
 		atomic.AddInt64(&stats.lines, 1)
 		atomic.AddInt64(&stats.bytes, int64(len(data)))
@@ -1387,6 +1489,14 @@ func InfoSDepth(depth int, msg string, keysAndValues ...interface{}) {
 	logging.infoS(logging.logr, logging.filter, depth, msg, keysAndValues...)
 }
 
+// InfoSDepth is equivalent to the global InfoSDepth function, guarded by the value of v.
+// See the documentation of V for usage.
+func (v Verbose) InfoSDepth(depth int, msg string, keysAndValues ...interface{}) {
+	if v.enabled {
+		logging.infoS(v.logr, v.filter, depth, msg, keysAndValues...)
+	}
+}
+
 // Deprecated: Use ErrorS instead.
 func (v Verbose) Error(err error, msg string, args ...interface{}) {
 	if v.enabled {