TUN-9467: bump coredns to solve CVE

* TUN-9467: bump coredns to solve CVE

vendor/github.com/prometheus/common/expfmt/decode.go

@@ -45,7 +45,7 @@ func ResponseFormat(h http.Header) Format {
 
 	mediatype, params, err := mime.ParseMediaType(ct)
 	if err != nil {
-		return fmtUnknown
+		return FmtUnknown
 	}
 
 	const textType = "text/plain"
@@ -53,21 +53,21 @@ func ResponseFormat(h http.Header) Format {
 	switch mediatype {
 	case ProtoType:
 		if p, ok := params["proto"]; ok && p != ProtoProtocol {
-			return fmtUnknown
+			return FmtUnknown
 		}
 		if e, ok := params["encoding"]; ok && e != "delimited" {
-			return fmtUnknown
+			return FmtUnknown
 		}
-		return fmtProtoDelim
+		return FmtProtoDelim
 
 	case textType:
 		if v, ok := params["version"]; ok && v != TextVersion {
-			return fmtUnknown
+			return FmtUnknown
 		}
-		return fmtText
+		return FmtText
 	}
 
-	return fmtUnknown
+	return FmtUnknown
 }
 
 // NewDecoder returns a new decoder based on the given input format.

vendor/github.com/prometheus/common/expfmt/encode.go

@@ -21,9 +21,10 @@ import (
 	"google.golang.org/protobuf/encoding/protodelim"
 	"google.golang.org/protobuf/encoding/prototext"
 
-	"github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg"
 	"github.com/prometheus/common/model"
 
+	"github.com/munnerz/goautoneg"
+
 	dto "github.com/prometheus/client_model/go"
 )
 
@@ -67,7 +68,7 @@ func Negotiate(h http.Header) Format {
 		if escapeParam := ac.Params[model.EscapingKey]; escapeParam != "" {
 			switch Format(escapeParam) {
 			case model.AllowUTF8, model.EscapeUnderscores, model.EscapeDots, model.EscapeValues:
-				escapingScheme = Format(fmt.Sprintf("; escaping=%s", escapeParam))
+				escapingScheme = Format("; escaping=" + escapeParam)
 			default:
 				// If the escaping parameter is unknown, ignore it.
 			}
@@ -76,18 +77,18 @@ func Negotiate(h http.Header) Format {
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
-				return fmtProtoDelim + escapingScheme
+				return FmtProtoDelim + escapingScheme
 			case "text":
-				return fmtProtoText + escapingScheme
+				return FmtProtoText + escapingScheme
 			case "compact-text":
-				return fmtProtoCompact + escapingScheme
+				return FmtProtoCompact + escapingScheme
 			}
 		}
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
-			return fmtText + escapingScheme
+			return FmtText + escapingScheme
 		}
 	}
-	return fmtText + escapingScheme
+	return FmtText + escapingScheme
 }
 
 // NegotiateIncludingOpenMetrics works like Negotiate but includes
@@ -100,7 +101,7 @@ func NegotiateIncludingOpenMetrics(h http.Header) Format {
 		if escapeParam := ac.Params[model.EscapingKey]; escapeParam != "" {
 			switch Format(escapeParam) {
 			case model.AllowUTF8, model.EscapeUnderscores, model.EscapeDots, model.EscapeValues:
-				escapingScheme = Format(fmt.Sprintf("; escaping=%s", escapeParam))
+				escapingScheme = Format("; escaping=" + escapeParam)
 			default:
 				// If the escaping parameter is unknown, ignore it.
 			}
@@ -109,26 +110,26 @@ func NegotiateIncludingOpenMetrics(h http.Header) Format {
 		if ac.Type+"/"+ac.SubType == ProtoType && ac.Params["proto"] == ProtoProtocol {
 			switch ac.Params["encoding"] {
 			case "delimited":
-				return fmtProtoDelim + escapingScheme
+				return FmtProtoDelim + escapingScheme
 			case "text":
-				return fmtProtoText + escapingScheme
+				return FmtProtoText + escapingScheme
 			case "compact-text":
-				return fmtProtoCompact + escapingScheme
+				return FmtProtoCompact + escapingScheme
 			}
 		}
 		if ac.Type == "text" && ac.SubType == "plain" && (ver == TextVersion || ver == "") {
-			return fmtText + escapingScheme
+			return FmtText + escapingScheme
 		}
 		if ac.Type+"/"+ac.SubType == OpenMetricsType && (ver == OpenMetricsVersion_0_0_1 || ver == OpenMetricsVersion_1_0_0 || ver == "") {
 			switch ver {
 			case OpenMetricsVersion_1_0_0:
-				return fmtOpenMetrics_1_0_0 + escapingScheme
+				return FmtOpenMetrics_1_0_0 + escapingScheme
 			default:
-				return fmtOpenMetrics_0_0_1 + escapingScheme
+				return FmtOpenMetrics_0_0_1 + escapingScheme
 			}
 		}
 	}
-	return fmtText + escapingScheme
+	return FmtText + escapingScheme
 }
 
 // NewEncoder returns a new encoder based on content type negotiation. All

vendor/github.com/prometheus/common/expfmt/expfmt.go

@@ -15,7 +15,7 @@
 package expfmt
 
 import (
-	"fmt"
+	"errors"
 	"strings"
 
 	"github.com/prometheus/common/model"
@@ -32,24 +32,31 @@ type Format string
 // it on the wire, new content-type strings will have to be agreed upon and
 // added here.
 const (
-	TextVersion              = "0.0.4"
-	ProtoType                = `application/vnd.google.protobuf`
-	ProtoProtocol            = `io.prometheus.client.MetricFamily`
-	protoFmt                 = ProtoType + "; proto=" + ProtoProtocol + ";"
+	TextVersion   = "0.0.4"
+	ProtoType     = `application/vnd.google.protobuf`
+	ProtoProtocol = `io.prometheus.client.MetricFamily`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoCompact) instead.
+	ProtoFmt                 = ProtoType + "; proto=" + ProtoProtocol + ";"
 	OpenMetricsType          = `application/openmetrics-text`
 	OpenMetricsVersion_0_0_1 = "0.0.1"
 	OpenMetricsVersion_1_0_0 = "1.0.0"
 
-	// The Content-Type values for the different wire protocols. Note that these
-	// values are now unexported. If code was relying on comparisons to these
-	// constants, instead use FormatType().
-	fmtUnknown           Format = `<unknown>`
-	fmtText              Format = `text/plain; version=` + TextVersion + `; charset=utf-8`
-	fmtProtoDelim        Format = protoFmt + ` encoding=delimited`
-	fmtProtoText         Format = protoFmt + ` encoding=text`
-	fmtProtoCompact      Format = protoFmt + ` encoding=compact-text`
-	fmtOpenMetrics_1_0_0 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_1_0_0 + `; charset=utf-8`
-	fmtOpenMetrics_0_0_1 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_0_0_1 + `; charset=utf-8`
+	// The Content-Type values for the different wire protocols. Do not do direct
+	// comparisons to these constants, instead use the comparison functions.
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeUnknown) instead.
+	FmtUnknown Format = `<unknown>`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeTextPlain) instead.
+	FmtText Format = `text/plain; version=` + TextVersion + `; charset=utf-8`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoDelim) instead.
+	FmtProtoDelim Format = ProtoFmt + ` encoding=delimited`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoText) instead.
+	FmtProtoText Format = ProtoFmt + ` encoding=text`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeProtoCompact) instead.
+	FmtProtoCompact Format = ProtoFmt + ` encoding=compact-text`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeOpenMetrics) instead.
+	FmtOpenMetrics_1_0_0 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_1_0_0 + `; charset=utf-8`
+	// Deprecated: Use expfmt.NewFormat(expfmt.TypeOpenMetrics) instead.
+	FmtOpenMetrics_0_0_1 Format = OpenMetricsType + `; version=` + OpenMetricsVersion_0_0_1 + `; charset=utf-8`
 )
 
 const (
@@ -79,17 +86,17 @@ const (
 func NewFormat(t FormatType) Format {
 	switch t {
 	case TypeProtoCompact:
-		return fmtProtoCompact
+		return FmtProtoCompact
 	case TypeProtoDelim:
-		return fmtProtoDelim
+		return FmtProtoDelim
 	case TypeProtoText:
-		return fmtProtoText
+		return FmtProtoText
 	case TypeTextPlain:
-		return fmtText
+		return FmtText
 	case TypeOpenMetrics:
-		return fmtOpenMetrics_1_0_0
+		return FmtOpenMetrics_1_0_0
 	default:
-		return fmtUnknown
+		return FmtUnknown
 	}
 }
 
@@ -97,12 +104,35 @@ func NewFormat(t FormatType) Format {
 // specified version number.
 func NewOpenMetricsFormat(version string) (Format, error) {
 	if version == OpenMetricsVersion_0_0_1 {
-		return fmtOpenMetrics_0_0_1, nil
+		return FmtOpenMetrics_0_0_1, nil
 	}
 	if version == OpenMetricsVersion_1_0_0 {
-		return fmtOpenMetrics_1_0_0, nil
+		return FmtOpenMetrics_1_0_0, nil
 	}
-	return fmtUnknown, fmt.Errorf("unknown open metrics version string")
+	return FmtUnknown, errors.New("unknown open metrics version string")
+}
+
+// WithEscapingScheme returns a copy of Format with the specified escaping
+// scheme appended to the end. If an escaping scheme already exists it is
+// removed.
+func (f Format) WithEscapingScheme(s model.EscapingScheme) Format {
+	var terms []string
+	for _, p := range strings.Split(string(f), ";") {
+		toks := strings.Split(p, "=")
+		if len(toks) != 2 {
+			trimmed := strings.TrimSpace(p)
+			if len(trimmed) > 0 {
+				terms = append(terms, trimmed)
+			}
+			continue
+		}
+		key := strings.TrimSpace(toks[0])
+		if key != model.EscapingKey {
+			terms = append(terms, strings.TrimSpace(p))
+		}
+	}
+	terms = append(terms, model.EscapingKey+"="+s.String())
+	return Format(strings.Join(terms, "; "))
 }
 
 // FormatType deduces an overall FormatType for the given format.

vendor/github.com/prometheus/common/expfmt/openmetrics_create.go

@@ -38,7 +38,7 @@ type EncoderOption func(*encoderOption)
 
 // WithCreatedLines is an EncoderOption that configures the OpenMetrics encoder
 // to include _created lines (See
-// https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#counter-1).
+// https://github.com/prometheus/OpenMetrics/blob/v1.0.0/specification/OpenMetrics.md#counter-1).
 // Created timestamps can improve the accuracy of series reset detection, but
 // come with a bandwidth cost.
 //
@@ -102,7 +102,7 @@ func WithUnit() EncoderOption {
 //
 //   - According to the OM specs, the `# UNIT` line is optional, but if populated,
 //     the unit has to be present in the metric name as its suffix:
-//     (see https://github.com/OpenObservability/OpenMetrics/blob/main/specification/OpenMetrics.md#unit).
+//     (see https://github.com/prometheus/OpenMetrics/blob/v1.0.0/specification/OpenMetrics.md#unit).
 //     However, in order to accommodate any potential scenario where such a change in the
 //     metric name is not desirable, the users are here given the choice of either explicitly
 //     opt in, in case they wish for the unit to be included in the output AND in the metric name
@@ -152,8 +152,8 @@ func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily, options ...E
 	if metricType == dto.MetricType_COUNTER && strings.HasSuffix(compliantName, "_total") {
 		compliantName = name[:len(name)-6]
 	}
-	if toOM.withUnit && in.Unit != nil && !strings.HasSuffix(compliantName, fmt.Sprintf("_%s", *in.Unit)) {
-		compliantName = compliantName + fmt.Sprintf("_%s", *in.Unit)
+	if toOM.withUnit && in.Unit != nil && !strings.HasSuffix(compliantName, "_"+*in.Unit) {
+		compliantName = compliantName + "_" + *in.Unit
 	}
 
 	// Comments, first HELP, then TYPE.
@@ -477,7 +477,7 @@ func writeOpenMetricsNameAndLabelPairs(
 	if name != "" {
 		// If the name does not pass the legacy validity check, we must put the
 		// metric name inside the braces, quoted.
-		if !model.IsValidLegacyMetricName(model.LabelValue(name)) {
+		if !model.IsValidLegacyMetricName(name) {
 			metricInsideBraces = true
 			err := w.WriteByte(separator)
 			written++

vendor/github.com/prometheus/common/expfmt/text_create.go

@@ -354,7 +354,7 @@ func writeNameAndLabelPairs(
 	if name != "" {
 		// If the name does not pass the legacy validity check, we must put the
 		// metric name inside the braces.
-		if !model.IsValidLegacyMetricName(model.LabelValue(name)) {
+		if !model.IsValidLegacyMetricName(name) {
 			metricInsideBraces = true
 			err := w.WriteByte(separator)
 			written++
@@ -498,7 +498,7 @@ func writeInt(w enhancedWriter, i int64) (int, error) {
 // writeName writes a string as-is if it complies with the legacy naming
 // scheme, or escapes it in double quotes if not.
 func writeName(w enhancedWriter, name string) (int, error) {
-	if model.IsValidLegacyMetricName(model.LabelValue(name)) {
+	if model.IsValidLegacyMetricName(name) {
 		return w.WriteString(name)
 	}
 	var written int

vendor/github.com/prometheus/common/expfmt/text_parse.go

@@ -22,9 +22,9 @@ import (
 	"math"
 	"strconv"
 	"strings"
+	"unicode/utf8"
 
 	dto "github.com/prometheus/client_model/go"
-
 	"google.golang.org/protobuf/proto"
 
 	"github.com/prometheus/common/model"
@@ -60,6 +60,7 @@ type TextParser struct {
 	currentMF            *dto.MetricFamily
 	currentMetric        *dto.Metric
 	currentLabelPair     *dto.LabelPair
+	currentLabelPairs    []*dto.LabelPair // Temporarily stores label pairs while parsing a metric line.
 
 	// The remaining member variables are only used for summaries/histograms.
 	currentLabels map[string]string // All labels including '__name__' but excluding 'quantile'/'le'
@@ -74,6 +75,9 @@ type TextParser struct {
 	// count and sum of that summary/histogram.
 	currentIsSummaryCount, currentIsSummarySum     bool
 	currentIsHistogramCount, currentIsHistogramSum bool
+	// These indicate if the metric name from the current line being parsed is inside
+	// braces and if that metric name was found respectively.
+	currentMetricIsInsideBraces, currentMetricInsideBracesIsPresent bool
 }
 
 // TextToMetricFamilies reads 'in' as the simple and flat text-based exchange
@@ -137,12 +141,15 @@ func (p *TextParser) reset(in io.Reader) {
 	}
 	p.currentQuantile = math.NaN()
 	p.currentBucket = math.NaN()
+	p.currentMF = nil
 }
 
 // startOfLine represents the state where the next byte read from p.buf is the
 // start of a line (or whitespace leading up to it).
 func (p *TextParser) startOfLine() stateFn {
 	p.lineCount++
+	p.currentMetricIsInsideBraces = false
+	p.currentMetricInsideBracesIsPresent = false
 	if p.skipBlankTab(); p.err != nil {
 		// This is the only place that we expect to see io.EOF,
 		// which is not an error but the signal that we are done.
@@ -158,6 +165,9 @@ func (p *TextParser) startOfLine() stateFn {
 		return p.startComment
 	case '\n':
 		return p.startOfLine // Empty line, start the next one.
+	case '{':
+		p.currentMetricIsInsideBraces = true
+		return p.readingLabels
 	}
 	return p.readingMetricName
 }
@@ -275,6 +285,8 @@ func (p *TextParser) startLabelName() stateFn {
 		return nil // Unexpected end of input.
 	}
 	if p.currentByte == '}' {
+		p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPairs...)
+		p.currentLabelPairs = nil
 		if p.skipBlankTab(); p.err != nil {
 			return nil // Unexpected end of input.
 		}
@@ -287,6 +299,45 @@ func (p *TextParser) startLabelName() stateFn {
 		p.parseError(fmt.Sprintf("invalid label name for metric %q", p.currentMF.GetName()))
 		return nil
 	}
+	if p.skipBlankTabIfCurrentBlankTab(); p.err != nil {
+		return nil // Unexpected end of input.
+	}
+	if p.currentByte != '=' {
+		if p.currentMetricIsInsideBraces {
+			if p.currentMetricInsideBracesIsPresent {
+				p.parseError(fmt.Sprintf("multiple metric names for metric %q", p.currentMF.GetName()))
+				return nil
+			}
+			switch p.currentByte {
+			case ',':
+				p.setOrCreateCurrentMF()
+				if p.currentMF.Type == nil {
+					p.currentMF.Type = dto.MetricType_UNTYPED.Enum()
+				}
+				p.currentMetric = &dto.Metric{}
+				p.currentMetricInsideBracesIsPresent = true
+				return p.startLabelName
+			case '}':
+				p.setOrCreateCurrentMF()
+				if p.currentMF.Type == nil {
+					p.currentMF.Type = dto.MetricType_UNTYPED.Enum()
+				}
+				p.currentMetric = &dto.Metric{}
+				p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPairs...)
+				p.currentLabelPairs = nil
+				if p.skipBlankTab(); p.err != nil {
+					return nil // Unexpected end of input.
+				}
+				return p.readingValue
+			default:
+				p.parseError(fmt.Sprintf("unexpected end of metric name %q", p.currentByte))
+				return nil
+			}
+		}
+		p.parseError(fmt.Sprintf("expected '=' after label name, found %q", p.currentByte))
+		p.currentLabelPairs = nil
+		return nil
+	}
 	p.currentLabelPair = &dto.LabelPair{Name: proto.String(p.currentToken.String())}
 	if p.currentLabelPair.GetName() == string(model.MetricNameLabel) {
 		p.parseError(fmt.Sprintf("label name %q is reserved", model.MetricNameLabel))
@@ -294,25 +345,19 @@ func (p *TextParser) startLabelName() stateFn {
 	}
 	// Special summary/histogram treatment. Don't add 'quantile' and 'le'
 	// labels to 'real' labels.
-	if !(p.currentMF.GetType() == dto.MetricType_SUMMARY && p.currentLabelPair.GetName() == model.QuantileLabel) &&
-		!(p.currentMF.GetType() == dto.MetricType_HISTOGRAM && p.currentLabelPair.GetName() == model.BucketLabel) {
-		p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPair)
-	}
-	if p.skipBlankTabIfCurrentBlankTab(); p.err != nil {
-		return nil // Unexpected end of input.
-	}
-	if p.currentByte != '=' {
-		p.parseError(fmt.Sprintf("expected '=' after label name, found %q", p.currentByte))
-		return nil
+	if (p.currentMF.GetType() != dto.MetricType_SUMMARY || p.currentLabelPair.GetName() != model.QuantileLabel) &&
+		(p.currentMF.GetType() != dto.MetricType_HISTOGRAM || p.currentLabelPair.GetName() != model.BucketLabel) {
+		p.currentLabelPairs = append(p.currentLabelPairs, p.currentLabelPair)
 	}
 	// Check for duplicate label names.
 	labels := make(map[string]struct{})
-	for _, l := range p.currentMetric.Label {
+	for _, l := range p.currentLabelPairs {
 		lName := l.GetName()
 		if _, exists := labels[lName]; !exists {
 			labels[lName] = struct{}{}
 		} else {
 			p.parseError(fmt.Sprintf("duplicate label names for metric %q", p.currentMF.GetName()))
+			p.currentLabelPairs = nil
 			return nil
 		}
 	}
@@ -345,6 +390,7 @@ func (p *TextParser) startLabelValue() stateFn {
 			if p.currentQuantile, p.err = parseFloat(p.currentLabelPair.GetValue()); p.err != nil {
 				// Create a more helpful error message.
 				p.parseError(fmt.Sprintf("expected float as value for 'quantile' label, got %q", p.currentLabelPair.GetValue()))
+				p.currentLabelPairs = nil
 				return nil
 			}
 		} else {
@@ -371,12 +417,19 @@ func (p *TextParser) startLabelValue() stateFn {
 		return p.startLabelName
 
 	case '}':
+		if p.currentMF == nil {
+			p.parseError("invalid metric name")
+			return nil
+		}
+		p.currentMetric.Label = append(p.currentMetric.Label, p.currentLabelPairs...)
+		p.currentLabelPairs = nil
 		if p.skipBlankTab(); p.err != nil {
 			return nil // Unexpected end of input.
 		}
 		return p.readingValue
 	default:
 		p.parseError(fmt.Sprintf("unexpected end of label value %q", p.currentLabelPair.GetValue()))
+		p.currentLabelPairs = nil
 		return nil
 	}
 }
@@ -585,6 +638,8 @@ func (p *TextParser) readTokenUntilNewline(recognizeEscapeSequence bool) {
 				p.currentToken.WriteByte(p.currentByte)
 			case 'n':
 				p.currentToken.WriteByte('\n')
+			case '"':
+				p.currentToken.WriteByte('"')
 			default:
 				p.parseError(fmt.Sprintf("invalid escape sequence '\\%c'", p.currentByte))
 				return
@@ -610,13 +665,45 @@ func (p *TextParser) readTokenUntilNewline(recognizeEscapeSequence bool) {
 // but not into p.currentToken.
 func (p *TextParser) readTokenAsMetricName() {
 	p.currentToken.Reset()
+	// A UTF-8 metric name must be quoted and may have escaped characters.
+	quoted := false
+	escaped := false
 	if !isValidMetricNameStart(p.currentByte) {
 		return
 	}
-	for {
-		p.currentToken.WriteByte(p.currentByte)
+	for p.err == nil {
+		if escaped {
+			switch p.currentByte {
+			case '\\':
+				p.currentToken.WriteByte(p.currentByte)
+			case 'n':
+				p.currentToken.WriteByte('\n')
+			case '"':
+				p.currentToken.WriteByte('"')
+			default:
+				p.parseError(fmt.Sprintf("invalid escape sequence '\\%c'", p.currentByte))
+				return
+			}
+			escaped = false
+		} else {
+			switch p.currentByte {
+			case '"':
+				quoted = !quoted
+				if !quoted {
+					p.currentByte, p.err = p.buf.ReadByte()
+					return
+				}
+			case '\n':
+				p.parseError(fmt.Sprintf("metric name %q contains unescaped new-line", p.currentToken.String()))
+				return
+			case '\\':
+				escaped = true
+			default:
+				p.currentToken.WriteByte(p.currentByte)
+			}
+		}
 		p.currentByte, p.err = p.buf.ReadByte()
-		if p.err != nil || !isValidMetricNameContinuation(p.currentByte) {
+		if !isValidMetricNameContinuation(p.currentByte, quoted) || (!quoted && p.currentByte == ' ') {
 			return
 		}
 	}
@@ -628,13 +715,45 @@ func (p *TextParser) readTokenAsMetricName() {
 // but not into p.currentToken.
 func (p *TextParser) readTokenAsLabelName() {
 	p.currentToken.Reset()
+	// A UTF-8 label name must be quoted and may have escaped characters.
+	quoted := false
+	escaped := false
 	if !isValidLabelNameStart(p.currentByte) {
 		return
 	}
-	for {
-		p.currentToken.WriteByte(p.currentByte)
+	for p.err == nil {
+		if escaped {
+			switch p.currentByte {
+			case '\\':
+				p.currentToken.WriteByte(p.currentByte)
+			case 'n':
+				p.currentToken.WriteByte('\n')
+			case '"':
+				p.currentToken.WriteByte('"')
+			default:
+				p.parseError(fmt.Sprintf("invalid escape sequence '\\%c'", p.currentByte))
+				return
+			}
+			escaped = false
+		} else {
+			switch p.currentByte {
+			case '"':
+				quoted = !quoted
+				if !quoted {
+					p.currentByte, p.err = p.buf.ReadByte()
+					return
+				}
+			case '\n':
+				p.parseError(fmt.Sprintf("label name %q contains unescaped new-line", p.currentToken.String()))
+				return
+			case '\\':
+				escaped = true
+			default:
+				p.currentToken.WriteByte(p.currentByte)
+			}
+		}
 		p.currentByte, p.err = p.buf.ReadByte()
-		if p.err != nil || !isValidLabelNameContinuation(p.currentByte) {
+		if !isValidLabelNameContinuation(p.currentByte, quoted) || (!quoted && p.currentByte == '=') {
 			return
 		}
 	}
@@ -660,6 +779,7 @@ func (p *TextParser) readTokenAsLabelValue() {
 				p.currentToken.WriteByte('\n')
 			default:
 				p.parseError(fmt.Sprintf("invalid escape sequence '\\%c'", p.currentByte))
+				p.currentLabelPairs = nil
 				return
 			}
 			escaped = false
@@ -718,19 +838,19 @@ func (p *TextParser) setOrCreateCurrentMF() {
 }
 
 func isValidLabelNameStart(b byte) bool {
-	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_'
+	return (b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || b == '"'
 }
 
-func isValidLabelNameContinuation(b byte) bool {
-	return isValidLabelNameStart(b) || (b >= '0' && b <= '9')
+func isValidLabelNameContinuation(b byte, quoted bool) bool {
+	return isValidLabelNameStart(b) || (b >= '0' && b <= '9') || (quoted && utf8.ValidString(string(b)))
 }
 
 func isValidMetricNameStart(b byte) bool {
 	return isValidLabelNameStart(b) || b == ':'
 }
 
-func isValidMetricNameContinuation(b byte) bool {
-	return isValidLabelNameContinuation(b) || b == ':'
+func isValidMetricNameContinuation(b byte, quoted bool) bool {
+	return isValidLabelNameContinuation(b, quoted) || b == ':'
 }
 
 func isBlankOrTab(b byte) bool {
@@ -775,7 +895,7 @@ func histogramMetricName(name string) string {
 
 func parseFloat(s string) (float64, error) {
 	if strings.ContainsAny(s, "pP_") {
-		return 0, fmt.Errorf("unsupported character in float")
+		return 0, errors.New("unsupported character in float")
 	}
 	return strconv.ParseFloat(s, 64)
 }

vendor/github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg/README.txt

@@ -1,67 +0,0 @@
-PACKAGE
-
-package goautoneg
-import "bitbucket.org/ww/goautoneg"
-
-HTTP Content-Type Autonegotiation.
-
-The functions in this package implement the behaviour specified in
-http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
-
-Copyright (c) 2011, Open Knowledge Foundation Ltd.
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-    Redistributions of source code must retain the above copyright
-    notice, this list of conditions and the following disclaimer.
-
-    Redistributions in binary form must reproduce the above copyright
-    notice, this list of conditions and the following disclaimer in
-    the documentation and/or other materials provided with the
-    distribution.
-
-    Neither the name of the Open Knowledge Foundation Ltd. nor the
-    names of its contributors may be used to endorse or promote
-    products derived from this software without specific prior written
-    permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-
-FUNCTIONS
-
-func Negotiate(header string, alternatives []string) (content_type string)
-Negotiate the most appropriate content_type given the accept header
-and a list of alternatives.
-
-func ParseAccept(header string) (accept []Accept)
-Parse an Accept Header string returning a sorted list
-of clauses
-
-
-TYPES
-
-type Accept struct {
-    Type, SubType string
-    Q             float32
-    Params        map[string]string
-}
-Structure to represent a clause in an HTTP Accept Header
-
-
-SUBDIRECTORIES
-
-	.hg

vendor/github.com/prometheus/common/internal/bitbucket.org/ww/goautoneg/autoneg.go

@@ -1,160 +0,0 @@
-/*
-Copyright (c) 2011, Open Knowledge Foundation Ltd.
-All rights reserved.
-
-HTTP Content-Type Autonegotiation.
-
-The functions in this package implement the behaviour specified in
-http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-	Redistributions of source code must retain the above copyright
-	notice, this list of conditions and the following disclaimer.
-
-	Redistributions in binary form must reproduce the above copyright
-	notice, this list of conditions and the following disclaimer in
-	the documentation and/or other materials provided with the
-	distribution.
-
-	Neither the name of the Open Knowledge Foundation Ltd. nor the
-	names of its contributors may be used to endorse or promote
-	products derived from this software without specific prior written
-	permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-*/
-package goautoneg
-
-import (
-	"sort"
-	"strconv"
-	"strings"
-)
-
-// Structure to represent a clause in an HTTP Accept Header
-type Accept struct {
-	Type, SubType string
-	Q             float64
-	Params        map[string]string
-}
-
-// For internal use, so that we can use the sort interface
-type accept_slice []Accept
-
-func (accept accept_slice) Len() int {
-	slice := []Accept(accept)
-	return len(slice)
-}
-
-func (accept accept_slice) Less(i, j int) bool {
-	slice := []Accept(accept)
-	ai, aj := slice[i], slice[j]
-	if ai.Q > aj.Q {
-		return true
-	}
-	if ai.Type != "*" && aj.Type == "*" {
-		return true
-	}
-	if ai.SubType != "*" && aj.SubType == "*" {
-		return true
-	}
-	return false
-}
-
-func (accept accept_slice) Swap(i, j int) {
-	slice := []Accept(accept)
-	slice[i], slice[j] = slice[j], slice[i]
-}
-
-// Parse an Accept Header string returning a sorted list
-// of clauses
-func ParseAccept(header string) (accept []Accept) {
-	parts := strings.Split(header, ",")
-	accept = make([]Accept, 0, len(parts))
-	for _, part := range parts {
-		part := strings.Trim(part, " ")
-
-		a := Accept{}
-		a.Params = make(map[string]string)
-		a.Q = 1.0
-
-		mrp := strings.Split(part, ";")
-
-		media_range := mrp[0]
-		sp := strings.Split(media_range, "/")
-		a.Type = strings.Trim(sp[0], " ")
-
-		switch {
-		case len(sp) == 1 && a.Type == "*":
-			a.SubType = "*"
-		case len(sp) == 2:
-			a.SubType = strings.Trim(sp[1], " ")
-		default:
-			continue
-		}
-
-		if len(mrp) == 1 {
-			accept = append(accept, a)
-			continue
-		}
-
-		for _, param := range mrp[1:] {
-			sp := strings.SplitN(param, "=", 2)
-			if len(sp) != 2 {
-				continue
-			}
-			token := strings.Trim(sp[0], " ")
-			if token == "q" {
-				a.Q, _ = strconv.ParseFloat(sp[1], 32)
-			} else {
-				a.Params[token] = strings.Trim(sp[1], " ")
-			}
-		}
-
-		accept = append(accept, a)
-	}
-
-	slice := accept_slice(accept)
-	sort.Sort(slice)
-
-	return
-}
-
-// Negotiate the most appropriate content_type given the accept header
-// and a list of alternatives.
-func Negotiate(header string, alternatives []string) (content_type string) {
-	asp := make([][]string, 0, len(alternatives))
-	for _, ctype := range alternatives {
-		asp = append(asp, strings.SplitN(ctype, "/", 2))
-	}
-	for _, clause := range ParseAccept(header) {
-		for i, ctsp := range asp {
-			if clause.Type == ctsp[0] && clause.SubType == ctsp[1] {
-				content_type = alternatives[i]
-				return
-			}
-			if clause.Type == ctsp[0] && clause.SubType == "*" {
-				content_type = alternatives[i]
-				return
-			}
-			if clause.Type == "*" && clause.SubType == "*" {
-				content_type = alternatives[i]
-				return
-			}
-		}
-	}
-	return
-}

vendor/github.com/prometheus/common/model/alert.go

@@ -14,6 +14,7 @@
 package model
 
 import (
+	"errors"
 	"fmt"
 	"time"
 )
@@ -64,7 +65,7 @@ func (a *Alert) Resolved() bool {
 	return a.ResolvedAt(time.Now())
 }
 
-// ResolvedAt returns true off the activity interval ended before
+// ResolvedAt returns true iff the activity interval ended before
 // the given timestamp.
 func (a *Alert) ResolvedAt(ts time.Time) bool {
 	if a.EndsAt.IsZero() {
@@ -89,16 +90,16 @@ func (a *Alert) StatusAt(ts time.Time) AlertStatus {
 // Validate checks whether the alert data is inconsistent.
 func (a *Alert) Validate() error {
 	if a.StartsAt.IsZero() {
-		return fmt.Errorf("start time missing")
+		return errors.New("start time missing")
 	}
 	if !a.EndsAt.IsZero() && a.EndsAt.Before(a.StartsAt) {
-		return fmt.Errorf("start time must be before end time")
+		return errors.New("start time must be before end time")
 	}
 	if err := a.Labels.Validate(); err != nil {
 		return fmt.Errorf("invalid label set: %w", err)
 	}
 	if len(a.Labels) == 0 {
-		return fmt.Errorf("at least one label pair required")
+		return errors.New("at least one label pair required")
 	}
 	if err := a.Annotations.Validate(); err != nil {
 		return fmt.Errorf("invalid annotations: %w", err)

vendor/github.com/prometheus/common/model/labels.go

@@ -22,7 +22,7 @@ import (
 )
 
 const (
-	// AlertNameLabel is the name of the label containing the an alert's name.
+	// AlertNameLabel is the name of the label containing the alert's name.
 	AlertNameLabel = "alertname"
 
 	// ExportedLabelPrefix is the prefix to prepend to the label names present in
@@ -97,26 +97,36 @@ var LabelNameRE = regexp.MustCompile("^[a-zA-Z_][a-zA-Z0-9_]*$")
 // therewith.
 type LabelName string
 
-// IsValid returns true iff name matches the pattern of LabelNameRE for legacy
-// names, and iff it's valid UTF-8 if NameValidationScheme is set to
-// UTF8Validation. For the legacy matching, it does not use LabelNameRE for the
-// check but a much faster hardcoded implementation.
+// IsValid returns true iff the name matches the pattern of LabelNameRE when
+// NameValidationScheme is set to LegacyValidation, or valid UTF-8 if
+// NameValidationScheme is set to UTF8Validation.
 func (ln LabelName) IsValid() bool {
 	if len(ln) == 0 {
 		return false
 	}
 	switch NameValidationScheme {
 	case LegacyValidation:
-		for i, b := range ln {
-			if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || (b >= '0' && b <= '9' && i > 0)) {
-				return false
-			}
-		}
+		return ln.IsValidLegacy()
 	case UTF8Validation:
 		return utf8.ValidString(string(ln))
 	default:
 		panic(fmt.Sprintf("Invalid name validation scheme requested: %d", NameValidationScheme))
 	}
+}
+
+// IsValidLegacy returns true iff name matches the pattern of LabelNameRE for
+// legacy names. It does not use LabelNameRE for the check but a much faster
+// hardcoded implementation.
+func (ln LabelName) IsValidLegacy() bool {
+	if len(ln) == 0 {
+		return false
+	}
+	for i, b := range ln {
+		// TODO: Apply De Morgan's law. Make sure there are tests for this.
+		if !((b >= 'a' && b <= 'z') || (b >= 'A' && b <= 'Z') || b == '_' || (b >= '0' && b <= '9' && i > 0)) { //nolint:staticcheck
+			return false
+		}
+	}
 	return true
 }
 

vendor/github.com/prometheus/common/model/labelset_string.go

@@ -11,8 +11,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build go1.21
-
 package model
 
 import (

vendor/github.com/prometheus/common/model/labelset_string_go120.go

@@ -1,39 +0,0 @@
-// Copyright 2024 The Prometheus Authors
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//go:build !go1.21
-
-package model
-
-import (
-	"fmt"
-	"sort"
-	"strings"
-)
-
-// String was optimized using functions not available for go 1.20
-// or lower. We keep the old implementation for compatibility with client_golang.
-// Once client golang drops support for go 1.20 (scheduled for August 2024), this
-// file can be removed.
-func (l LabelSet) String() string {
-	labelNames := make([]string, 0, len(l))
-	for name := range l {
-		labelNames = append(labelNames, string(name))
-	}
-	sort.Strings(labelNames)
-	lstrs := make([]string, 0, len(l))
-	for _, name := range labelNames {
-		lstrs = append(lstrs, fmt.Sprintf("%s=%q", name, l[LabelName(name)]))
-	}
-	return fmt.Sprintf("{%s}", strings.Join(lstrs, ", "))
-}

vendor/github.com/prometheus/common/model/metric.go

@@ -14,9 +14,11 @@
 package model
 
 import (
+	"errors"
 	"fmt"
 	"regexp"
 	"sort"
+	"strconv"
 	"strings"
 	"unicode/utf8"
 
@@ -25,19 +27,34 @@ import (
 )
 
 var (
-	// NameValidationScheme determines the method of name validation to be used by
-	// all calls to IsValidMetricName() and LabelName IsValid(). Setting UTF-8 mode
-	// in isolation from other components that don't support UTF-8 may result in
-	// bugs or other undefined behavior. This value is intended to be set by
-	// UTF-8-aware binaries as part of their startup. To avoid need for locking,
-	// this value should be set once, ideally in an init(), before multiple
-	// goroutines are started.
-	NameValidationScheme = LegacyValidation
+	// NameValidationScheme determines the global default method of the name
+	// validation to be used by all calls to IsValidMetricName() and LabelName
+	// IsValid().
+	//
+	// Deprecated: This variable should not be used and might be removed in the
+	// far future. If you wish to stick to the legacy name validation use
+	// `IsValidLegacyMetricName()` and `LabelName.IsValidLegacy()` methods
+	// instead. This variable is here as an escape hatch for emergency cases,
+	// given the recent change from `LegacyValidation` to `UTF8Validation`, e.g.,
+	// to delay UTF-8 migrations in time or aid in debugging unforeseen results of
+	// the change. In such a case, a temporary assignment to `LegacyValidation`
+	// value in the `init()` function in your main.go or so, could be considered.
+	//
+	// Historically we opted for a global variable for feature gating different
+	// validation schemes in operations that were not otherwise easily adjustable
+	// (e.g. Labels yaml unmarshaling). That could have been a mistake, a separate
+	// Labels structure or package might have been a better choice. Given the
+	// change was made and many upgraded the common already, we live this as-is
+	// with this warning and learning for the future.
+	NameValidationScheme = UTF8Validation
 
-	// NameEscapingScheme defines the default way that names will be
-	// escaped when presented to systems that do not support UTF-8 names. If the
-	// Content-Type "escaping" term is specified, that will override this value.
-	NameEscapingScheme = ValueEncodingEscaping
+	// NameEscapingScheme defines the default way that names will be escaped when
+	// presented to systems that do not support UTF-8 names. If the Content-Type
+	// "escaping" term is specified, that will override this value.
+	// NameEscapingScheme should not be set to the NoEscaping value. That string
+	// is used in content negotiation to indicate that a system supports UTF-8 and
+	// has that feature enabled.
+	NameEscapingScheme = UnderscoreEscaping
 )
 
 // ValidationScheme is a Go enum for determining how metric and label names will
@@ -45,7 +62,7 @@ var (
 type ValidationScheme int
 
 const (
-	// LegacyValidation is a setting that requirets that metric and label names
+	// LegacyValidation is a setting that requires that all metric and label names
 	// conform to the original Prometheus character requirements described by
 	// MetricNameRE and LabelNameRE.
 	LegacyValidation ValidationScheme = iota
@@ -161,7 +178,7 @@ func (m Metric) FastFingerprint() Fingerprint {
 func IsValidMetricName(n LabelValue) bool {
 	switch NameValidationScheme {
 	case LegacyValidation:
-		return IsValidLegacyMetricName(n)
+		return IsValidLegacyMetricName(string(n))
 	case UTF8Validation:
 		if len(n) == 0 {
 			return false
@@ -176,7 +193,7 @@ func IsValidMetricName(n LabelValue) bool {
 // legacy validation scheme regardless of the value of NameValidationScheme.
 // This function, however, does not use MetricNameRE for the check but a much
 // faster hardcoded implementation.
-func IsValidLegacyMetricName(n LabelValue) bool {
+func IsValidLegacyMetricName(n string) bool {
 	if len(n) == 0 {
 		return false
 	}
@@ -208,7 +225,7 @@ func EscapeMetricFamily(v *dto.MetricFamily, scheme EscapingScheme) *dto.MetricF
 	}
 
 	// If the name is nil, copy as-is, don't try to escape.
-	if v.Name == nil || IsValidLegacyMetricName(LabelValue(v.GetName())) {
+	if v.Name == nil || IsValidLegacyMetricName(v.GetName()) {
 		out.Name = v.Name
 	} else {
 		out.Name = proto.String(EscapeName(v.GetName(), scheme))
@@ -230,7 +247,7 @@ func EscapeMetricFamily(v *dto.MetricFamily, scheme EscapingScheme) *dto.MetricF
 
 		for _, l := range m.Label {
 			if l.GetName() == MetricNameLabel {
-				if l.Value == nil || IsValidLegacyMetricName(LabelValue(l.GetValue())) {
+				if l.Value == nil || IsValidLegacyMetricName(l.GetValue()) {
 					escaped.Label = append(escaped.Label, l)
 					continue
 				}
@@ -240,7 +257,7 @@ func EscapeMetricFamily(v *dto.MetricFamily, scheme EscapingScheme) *dto.MetricF
 				})
 				continue
 			}
-			if l.Name == nil || IsValidLegacyMetricName(LabelValue(l.GetName())) {
+			if l.Name == nil || IsValidLegacyMetricName(l.GetName()) {
 				escaped.Label = append(escaped.Label, l)
 				continue
 			}
@@ -256,20 +273,16 @@ func EscapeMetricFamily(v *dto.MetricFamily, scheme EscapingScheme) *dto.MetricF
 
 func metricNeedsEscaping(m *dto.Metric) bool {
 	for _, l := range m.Label {
-		if l.GetName() == MetricNameLabel && !IsValidLegacyMetricName(LabelValue(l.GetValue())) {
+		if l.GetName() == MetricNameLabel && !IsValidLegacyMetricName(l.GetValue()) {
 			return true
 		}
-		if !IsValidLegacyMetricName(LabelValue(l.GetName())) {
+		if !IsValidLegacyMetricName(l.GetName()) {
 			return true
 		}
 	}
 	return false
 }
 
-const (
-	lowerhex = "0123456789abcdef"
-)
-
 // EscapeName escapes the incoming name according to the provided escaping
 // scheme. Depending on the rules of escaping, this may cause no change in the
 // string that is returned. (Especially NoEscaping, which by definition is a
@@ -283,7 +296,7 @@ func EscapeName(name string, scheme EscapingScheme) string {
 	case NoEscaping:
 		return name
 	case UnderscoreEscaping:
-		if IsValidLegacyMetricName(LabelValue(name)) {
+		if IsValidLegacyMetricName(name) {
 			return name
 		}
 		for i, b := range name {
@@ -304,31 +317,25 @@ func EscapeName(name string, scheme EscapingScheme) string {
 			} else if isValidLegacyRune(b, i) {
 				escaped.WriteRune(b)
 			} else {
-				escaped.WriteRune('_')
+				escaped.WriteString("__")
 			}
 		}
 		return escaped.String()
 	case ValueEncodingEscaping:
-		if IsValidLegacyMetricName(LabelValue(name)) {
+		if IsValidLegacyMetricName(name) {
 			return name
 		}
 		escaped.WriteString("U__")
 		for i, b := range name {
-			if isValidLegacyRune(b, i) {
+			if b == '_' {
+				escaped.WriteString("__")
+			} else if isValidLegacyRune(b, i) {
 				escaped.WriteRune(b)
 			} else if !utf8.ValidRune(b) {
 				escaped.WriteString("_FFFD_")
-			} else if b < 0x100 {
+			} else {
 				escaped.WriteRune('_')
-				for s := 4; s >= 0; s -= 4 {
-					escaped.WriteByte(lowerhex[b>>uint(s)&0xF])
-				}
-				escaped.WriteRune('_')
-			} else if b < 0x10000 {
-				escaped.WriteRune('_')
-				for s := 12; s >= 0; s -= 4 {
-					escaped.WriteByte(lowerhex[b>>uint(s)&0xF])
-				}
+				escaped.WriteString(strconv.FormatInt(int64(b), 16))
 				escaped.WriteRune('_')
 			}
 		}
@@ -386,8 +393,9 @@ func UnescapeName(name string, scheme EscapingScheme) string {
 			// We think we are in a UTF-8 code, process it.
 			var utf8Val uint
 			for j := 0; i < len(escapedName); j++ {
-				// This is too many characters for a utf8 value.
-				if j > 4 {
+				// This is too many characters for a utf8 value based on the MaxRune
+				// value of '\U0010FFFF'.
+				if j >= 6 {
 					return name
 				}
 				// Found a closing underscore, convert to a rune, check validity, and append.
@@ -440,7 +448,7 @@ func (e EscapingScheme) String() string {
 
 func ToEscapingScheme(s string) (EscapingScheme, error) {
 	if s == "" {
-		return NoEscaping, fmt.Errorf("got empty string instead of escaping scheme")
+		return NoEscaping, errors.New("got empty string instead of escaping scheme")
 	}
 	switch s {
 	case AllowUTF8:
@@ -452,6 +460,6 @@ func ToEscapingScheme(s string) (EscapingScheme, error) {
 	case EscapeValues:
 		return ValueEncodingEscaping, nil
 	default:
-		return NoEscaping, fmt.Errorf("unknown format scheme " + s)
+		return NoEscaping, fmt.Errorf("unknown format scheme %s", s)
 	}
 }

vendor/github.com/prometheus/common/model/silence.go

@@ -15,6 +15,7 @@ package model
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"regexp"
 	"time"
@@ -34,7 +35,7 @@ func (m *Matcher) UnmarshalJSON(b []byte) error {
 	}
 
 	if len(m.Name) == 0 {
-		return fmt.Errorf("label name in matcher must not be empty")
+		return errors.New("label name in matcher must not be empty")
 	}
 	if m.IsRegex {
 		if _, err := regexp.Compile(m.Value); err != nil {
@@ -77,7 +78,7 @@ type Silence struct {
 // Validate returns true iff all fields of the silence have valid values.
 func (s *Silence) Validate() error {
 	if len(s.Matchers) == 0 {
-		return fmt.Errorf("at least one matcher required")
+		return errors.New("at least one matcher required")
 	}
 	for _, m := range s.Matchers {
 		if err := m.Validate(); err != nil {
@@ -85,22 +86,22 @@ func (s *Silence) Validate() error {
 		}
 	}
 	if s.StartsAt.IsZero() {
-		return fmt.Errorf("start time missing")
+		return errors.New("start time missing")
 	}
 	if s.EndsAt.IsZero() {
-		return fmt.Errorf("end time missing")
+		return errors.New("end time missing")
 	}
 	if s.EndsAt.Before(s.StartsAt) {
-		return fmt.Errorf("start time must be before end time")
+		return errors.New("start time must be before end time")
 	}
 	if s.CreatedBy == "" {
-		return fmt.Errorf("creator information missing")
+		return errors.New("creator information missing")
 	}
 	if s.Comment == "" {
-		return fmt.Errorf("comment missing")
+		return errors.New("comment missing")
 	}
 	if s.CreatedAt.IsZero() {
-		return fmt.Errorf("creation timestamp missing")
+		return errors.New("creation timestamp missing")
 	}
 	return nil
 }

vendor/github.com/prometheus/common/model/value_float.go

@@ -15,6 +15,7 @@ package model
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"math"
 	"strconv"
@@ -39,7 +40,7 @@ func (v SampleValue) MarshalJSON() ([]byte, error) {
 // UnmarshalJSON implements json.Unmarshaler.
 func (v *SampleValue) UnmarshalJSON(b []byte) error {
 	if len(b) < 2 || b[0] != '"' || b[len(b)-1] != '"' {
-		return fmt.Errorf("sample value must be a quoted string")
+		return errors.New("sample value must be a quoted string")
 	}
 	f, err := strconv.ParseFloat(string(b[1:len(b)-1]), 64)
 	if err != nil {

vendor/github.com/prometheus/common/model/value_histogram.go

@@ -15,6 +15,7 @@ package model
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"strconv"
 	"strings"
@@ -32,7 +33,7 @@ func (v FloatString) MarshalJSON() ([]byte, error) {
 
 func (v *FloatString) UnmarshalJSON(b []byte) error {
 	if len(b) < 2 || b[0] != '"' || b[len(b)-1] != '"' {
-		return fmt.Errorf("float value must be a quoted string")
+		return errors.New("float value must be a quoted string")
 	}
 	f, err := strconv.ParseFloat(string(b[1:len(b)-1]), 64)
 	if err != nil {
@@ -141,7 +142,7 @@ type SampleHistogramPair struct {
 
 func (s SampleHistogramPair) MarshalJSON() ([]byte, error) {
 	if s.Histogram == nil {
-		return nil, fmt.Errorf("histogram is nil")
+		return nil, errors.New("histogram is nil")
 	}
 	t, err := json.Marshal(s.Timestamp)
 	if err != nil {
@@ -164,7 +165,7 @@ func (s *SampleHistogramPair) UnmarshalJSON(buf []byte) error {
 		return fmt.Errorf("wrong number of fields: %d != %d", gotLen, wantLen)
 	}
 	if s.Histogram == nil {
-		return fmt.Errorf("histogram is null")
+		return errors.New("histogram is null")
 	}
 	return nil
 }