util/promlint/promlint.go
func (l *Linter) Lint() ([]Problem, error) {
	// TODO(mdlayher): support for protobuf exposition format?
	d := expfmt.NewDecoder(l.r, expfmt.FmtText)

	var problems []Problem

	var mf dto.MetricFamily
	for {
		if err := d.Decode(&mf); err != nil {
			if err == io.EOF {
				break
			}

			return nil, err
		}

		problems = append(problems, lint(mf)...)
	}

	// Ensure deterministic output.
	sort.SliceStable(problems, func(i, j int) bool {
		if problems[i].Metric < problems[j].Metric {
			return true
		}

		return problems[i].Text < problems[j].Text
	})

	return problems, nil
}
func (l *Linter) Lint() ([]Problem, error) {
	// TODO(mdlayher): support for protobuf exposition format?
	d := expfmt.NewDecoder(l.r, expfmt.FmtText)

	var problems []Problem

	var mf dto.MetricFamily
	for {
		if err := d.Decode(&mf); err != nil {
			if err == io.EOF {
				break
			}

			return nil, err
		}

		problems = append(problems, lint(mf)...)
	}

	// Ensure deterministic output.
	sort.SliceStable(problems, func(i, j int) bool {
		if problems[i].Metric < problems[j].Metric {
			return true
		}

		return problems[i].Text < problems[j].Text
	})

	return problems, nil
}
// Lint performs a linting pass, returning a slice of Problems indicating any
// issues found in the metrics stream.  The slice is sorted by metric name
// and issue description.