feat(format): output findings summary for text formatter

cmd/decolint/config_test.go

@@ -23,16 +23,16 @@ func TestParseConfig(t *testing.T) {
 		{
 			"jsonc with comments and trailing comma",
 			"{\n  // override severities\n  \"rules\": {\n    \"no-image-latest\": \"error\",\n  },\n}\n",
-			Config{Rules: map[string]linter.Severity{"no-image-latest": linter.Error}},
+			Config{Rules: map[string]linter.Severity{"no-image-latest": linter.SeverityError}},
 			false,
 		},
 		{
 			"multiple rules",
 			`{"rules": {"no-image-latest": "error", "pin-image-digest": "warn", "require-non-root": "off"}}`,
 			Config{Rules: map[string]linter.Severity{
-				"no-image-latest":  linter.Error,
-				"pin-image-digest": linter.Warn,
-				"require-non-root": linter.Off,
+				"no-image-latest":  linter.SeverityError,
+				"pin-image-digest": linter.SeverityWarn,
+				"require-non-root": linter.SeverityOff,
 			}},
 			false,
 		},
@@ -76,7 +76,7 @@ func TestLoadConfigExplicitPath(t *testing.T) {
 		if err != nil {
 			t.Fatalf("loadConfig: %v", err)
 		}
-		want := Config{Rules: map[string]linter.Severity{"no-image-latest": linter.Error}}
+		want := Config{Rules: map[string]linter.Severity{"no-image-latest": linter.SeverityError}}
 		if diff := cmp.Diff(want, got); diff != "" {
 			t.Errorf("loadConfig() mismatch (-want +got):\n%s", diff)
 		}
@@ -94,20 +94,20 @@ func TestLoadConfigDiscovery(t *testing.T) {
 		{
 			".decolint.jsonc present",
 			map[string]string{".decolint.jsonc": `{"rules": {"no-image-latest": "error"}}`},
-			Config{Rules: map[string]linter.Severity{"no-image-latest": linter.Error}},
+			Config{Rules: map[string]linter.Severity{"no-image-latest": linter.SeverityError}},
 		},
 		{
 			".decolint.json fallback",
 			map[string]string{".decolint.json": `{"rules": {"no-image-latest": "warn"}}`},
-			Config{Rules: map[string]linter.Severity{"no-image-latest": linter.Warn}},
+			Config{Rules: map[string]linter.Severity{"no-image-latest": linter.SeverityWarn}},
 		},
 		{
 			".decolint.jsonc takes precedence over .decolint.json",
 			map[string]string{
 				".decolint.jsonc": `{"rules": {"no-image-latest": "error"}}`,
 				".decolint.json":  `{"rules": {"no-image-latest": "warn"}}`,
 			},
-			Config{Rules: map[string]linter.Severity{"no-image-latest": linter.Error}},
+			Config{Rules: map[string]linter.Severity{"no-image-latest": linter.SeverityError}},
 		},
 	}
 	for _, tt := range tests {

cmd/decolint/main.go

@@ -20,7 +20,7 @@ import (
 const progName = "decolint"
 
 // failThreshold is the default lowest severity that causes exit code 1.
-const failThreshold = linter.Error
+const failThreshold = linter.SeverityError
 
 const (
 	exitCodeSuccess     = 0
@@ -97,9 +97,9 @@ func versionString() string {
 
 // severityEmoji renders a severity for the -rules table; see the legend printed above the table.
 var severityEmoji = map[linter.Severity]string{
-	linter.Off:   "",
-	linter.Warn:  "🟡 WARN",
-	linter.Error: "🔴 ERROR",
+	linter.SeverityOff:   "",
+	linter.SeverityWarn:  "🟡 WARN",
+	linter.SeverityError: "🔴 ERROR",
 }
 
 // rulesTableHeader is the header row of the -rules Markdown table.
@@ -218,7 +218,7 @@ Flags:
 func runLint(ctx context.Context, stdout io.Writer, opts Options) (bool, error) {
 	threshold := failThreshold
 	if opts.DenyWarnings {
-		threshold = linter.Warn
+		threshold = linter.SeverityWarn
 	}
 
 	l := linter.New()

cmd/decolint/main_test.go

@@ -40,12 +40,12 @@ func TestRun(t *testing.T) {
 				// The fixture uses every ignore directive kind, each suppressing a rule that would
 				// otherwise fire: decolint-ignore-file (no-seccomp-unconfined), decolint-ignore-line
 				// (no-cap-add-all), and decolint-ignore-next-line (no-app-port).
-				{violationsFile, "no-bind-mount", linter.Warn},
-				{violationsFile, "no-host-port-format", linter.Error},
-				{violationsFile, "no-docker-socket-mount", linter.Warn},
-				{violationsFile, "no-image-latest", linter.Warn},
-				{violationsFile, "no-privileged-container", linter.Warn},
-				{violationsFile, "pin-feature-version", linter.Warn},
+				{violationsFile, "no-bind-mount", linter.SeverityWarn},
+				{violationsFile, "no-host-port-format", linter.SeverityError},
+				{violationsFile, "no-docker-socket-mount", linter.SeverityWarn},
+				{violationsFile, "no-image-latest", linter.SeverityWarn},
+				{violationsFile, "no-privileged-container", linter.SeverityWarn},
+				{violationsFile, "pin-feature-version", linter.SeverityWarn},
 			},
 			wantExitCode: 1, // no-host-port-format is an error by default
 		},
@@ -55,21 +55,21 @@ func TestRun(t *testing.T) {
 			name: "violations without platform selection",
 			args: []string{"testdata/e2e/violations"},
 			want: []firing{
-				{violationsFile, "no-docker-socket-mount", linter.Warn},
-				{violationsFile, "no-image-latest", linter.Warn},
-				{violationsFile, "no-privileged-container", linter.Warn},
-				{violationsFile, "pin-feature-version", linter.Warn},
+				{violationsFile, "no-docker-socket-mount", linter.SeverityWarn},
+				{violationsFile, "no-image-latest", linter.SeverityWarn},
+				{violationsFile, "no-privileged-container", linter.SeverityWarn},
+				{violationsFile, "pin-feature-version", linter.SeverityWarn},
 			},
 			wantExitCode: 0,
 		},
 		{
 			name: "violations with deny-warnings",
 			args: []string{"-deny-warnings", "testdata/e2e/violations"},
 			want: []firing{
-				{violationsFile, "no-docker-socket-mount", linter.Warn},
-				{violationsFile, "no-image-latest", linter.Warn},
-				{violationsFile, "no-privileged-container", linter.Warn},
-				{violationsFile, "pin-feature-version", linter.Warn},
+				{violationsFile, "no-docker-socket-mount", linter.SeverityWarn},
+				{violationsFile, "no-image-latest", linter.SeverityWarn},
+				{violationsFile, "no-privileged-container", linter.SeverityWarn},
+				{violationsFile, "pin-feature-version", linter.SeverityWarn},
 			},
 			wantExitCode: 1, // warnings now cross the fail threshold
 		},
@@ -83,12 +83,12 @@ func TestRun(t *testing.T) {
 				"testdata/e2e/violations",
 			},
 			want: []firing{
-				{violationsFile, "no-bind-mount", linter.Warn},
-				{violationsFile, "no-host-port-format", linter.Error},
-				{violationsFile, "no-docker-socket-mount", linter.Warn},
-				{violationsFile, "no-image-latest", linter.Error},
-				{violationsFile, "no-privileged-container", linter.Warn},
-				{violationsFile, "pin-image-digest", linter.Warn},
+				{violationsFile, "no-bind-mount", linter.SeverityWarn},
+				{violationsFile, "no-host-port-format", linter.SeverityError},
+				{violationsFile, "no-docker-socket-mount", linter.SeverityWarn},
+				{violationsFile, "no-image-latest", linter.SeverityError},
+				{violationsFile, "no-privileged-container", linter.SeverityWarn},
+				{violationsFile, "pin-image-digest", linter.SeverityWarn},
 			},
 			wantExitCode: 1,
 		},
@@ -177,13 +177,13 @@ func TestRun_Flags(t *testing.T) {
 		}
 
 		row := mdTableRow(t, out, "no-image-latest")
-		wantRow := []string{"no-image-latest", "(all)", severityEmoji[linter.Warn], severityEmoji[linter.Warn]}
+		wantRow := []string{"no-image-latest", "(all)", severityEmoji[linter.SeverityWarn], severityEmoji[linter.SeverityWarn]}
 		if diff := cmp.Diff(wantRow, row); diff != "" {
 			t.Errorf("no-image-latest row mismatch (-want +got):\n%s", diff)
 		}
 
 		row = mdTableRow(t, out, "no-bind-mount")
-		wantRow = []string{"no-bind-mount", "codespaces", severityEmoji[linter.Warn], severityEmoji[linter.Warn]}
+		wantRow = []string{"no-bind-mount", "codespaces", severityEmoji[linter.SeverityWarn], severityEmoji[linter.SeverityWarn]}
 		if diff := cmp.Diff(wantRow, row); diff != "" {
 			t.Errorf("no-bind-mount row mismatch (-want +got):\n%s", diff)
 		}
@@ -204,21 +204,21 @@ func TestRun_Flags(t *testing.T) {
 
 		// no-image-latest: default warn, overridden to error.
 		row := mdTableRow(t, out, "no-image-latest")
-		wantRow := []string{"no-image-latest", "(all)", severityEmoji[linter.Warn], severityEmoji[linter.Error]}
+		wantRow := []string{"no-image-latest", "(all)", severityEmoji[linter.SeverityWarn], severityEmoji[linter.SeverityError]}
 		if diff := cmp.Diff(wantRow, row); diff != "" {
 			t.Errorf("no-image-latest row mismatch (-want +got):\n%s", diff)
 		}
 
 		// pin-feature-version: default warn, overridden to off.
 		row = mdTableRow(t, out, "pin-feature-version")
-		wantRow = []string{"pin-feature-version", "(all)", severityEmoji[linter.Warn], severityEmoji[linter.Off]}
+		wantRow = []string{"pin-feature-version", "(all)", severityEmoji[linter.SeverityWarn], severityEmoji[linter.SeverityOff]}
 		if diff := cmp.Diff(wantRow, row); diff != "" {
 			t.Errorf("pin-feature-version row mismatch (-want +got):\n%s", diff)
 		}
 
 		// pin-image-digest: default off, overridden to warn.
 		row = mdTableRow(t, out, "pin-image-digest")
-		wantRow = []string{"pin-image-digest", "(all)", severityEmoji[linter.Off], severityEmoji[linter.Warn]}
+		wantRow = []string{"pin-image-digest", "(all)", severityEmoji[linter.SeverityOff], severityEmoji[linter.SeverityWarn]}
 		if diff := cmp.Diff(wantRow, row); diff != "" {
 			t.Errorf("pin-image-digest row mismatch (-want +got):\n%s", diff)
 		}
@@ -297,7 +297,7 @@ func TestRunLint(t *testing.T) {
 		opts := Options{
 			Paths:  []string{dir},
 			Format: format.TextFormat{},
-			Config: Config{Rules: map[string]linter.Severity{"no-image-latest": linter.Error}},
+			Config: Config{Rules: map[string]linter.Severity{"no-image-latest": linter.SeverityError}},
 		}
 		hasIssue, runErr := runLint(t.Context(), &stdout, opts)
 		if runErr != nil || !hasIssue {
@@ -313,7 +313,7 @@ func TestRunLint(t *testing.T) {
 		opts := Options{
 			Paths:  []string{dir},
 			Format: format.TextFormat{},
-			Config: Config{Rules: map[string]linter.Severity{"missing-container-def": linter.Off}},
+			Config: Config{Rules: map[string]linter.Severity{"missing-container-def": linter.SeverityOff}},
 		}
 		hasIssue, runErr := runLint(t.Context(), &stdout, opts)
 		if runErr != nil || hasIssue {
@@ -327,7 +327,7 @@ func TestRunLint(t *testing.T) {
 		var stdout bytes.Buffer
 		opts := Options{
 			Format: format.TextFormat{},
-			Config: Config{Rules: map[string]linter.Severity{"no-image-latst": linter.Error}},
+			Config: Config{Rules: map[string]linter.Severity{"no-image-latst": linter.SeverityError}},
 		}
 		hasIssue, runErr := runLint(t.Context(), &stdout, opts)
 		if runErr == nil || hasIssue {
@@ -346,7 +346,7 @@ func TestRunLint(t *testing.T) {
 		opts := Options{
 			Paths:  []string{dir},
 			Format: format.TextFormat{},
-			Config: Config{Rules: map[string]linter.Severity{"no-bind-mount": linter.Error}},
+			Config: Config{Rules: map[string]linter.Severity{"no-bind-mount": linter.SeverityError}},
 		}
 		hasIssue, runErr := runLint(t.Context(), &stdout, opts)
 		if runErr != nil || hasIssue {

format/github.go

@@ -15,7 +15,7 @@ type GitHubFormat struct{}
 func (GitHubFormat) WriteIssues(w io.Writer, issues []linter.Issue) error {
 	for _, issue := range issues {
 		command := "error"
-		if issue.Severity == linter.Warn {
+		if issue.Severity == linter.SeverityWarn {
 			command = "warning"
 		}
 		_, err := fmt.Fprintf(

format/text.go

@@ -12,10 +12,31 @@ type TextFormat struct{}
 
 // WriteIssues writes issues to w, one line per issue.
 func (TextFormat) WriteIssues(w io.Writer, issues []linter.Issue) error {
+	var numErrors, numWarnings int
+
 	for _, issue := range issues {
 		if _, err := fmt.Fprintln(w, issue); err != nil {
 			return err
 		}
+
+		switch issue.Severity {
+		case linter.SeverityError:
+			numErrors++
+		case linter.SeverityWarn:
+			numWarnings++
+		}
+	}
+
+	if _, err := fmt.Fprintf(w, "Found %d error%s and %d warning%s.\n", numErrors, pluralize(numErrors), numWarnings, pluralize(numWarnings)); err != nil {
+		return err
 	}
+
 	return nil
 }
+
+func pluralize(n int) string {
+	if n == 1 {
+		return ""
+	}
+	return "s"
+}

format/text_test.go

@@ -15,15 +15,15 @@ func testIssues() []linter.Issue {
 			Col:      12,
 			RuleID:   "no-image-latest",
 			Message:  `image "ubuntu:latest" uses the "latest" tag; pin a specific version`,
-			Severity: linter.Warn,
+			Severity: linter.SeverityWarn,
 		},
 		{
 			Path:     ".devcontainer/devcontainer.json",
 			Line:     8,
 			Col:      3,
 			RuleID:   "some-error-rule",
 			Message:  "something is broken",
-			Severity: linter.Error,
+			Severity: linter.SeverityError,
 		},
 	}
 }
@@ -38,6 +38,7 @@ func TestTextWriteIssues(t *testing.T) {
 
 	want := `.devcontainer/devcontainer.json:4:12: warn: image "ubuntu:latest" uses the "latest" tag; pin a specific version (no-image-latest)
 .devcontainer/devcontainer.json:8:3: error: something is broken (some-error-rule)
+Found 1 error and 1 warning.
 `
 	if sb.String() != want {
 		t.Errorf("WriteIssues text = %q, want %q", sb.String(), want)

linter/linter.go

@@ -51,7 +51,7 @@ func New() *Linter {
 // RegisterRule adds r to the linter, to run at the given severity.
 func (l *Linter) RegisterRule(r *Rule, severity Severity) {
 	l.severities[r.ID] = severity
-	if severity == Off {
+	if severity == SeverityOff {
 		return
 	}
 	for _, t := range r.FileTypes {

linter/linter_test.go

@@ -228,7 +228,7 @@ func TestLintRulePanicIsRecovered(t *testing.T) {
 	t.Parallel()
 
 	l := linter.New()
-	l.RegisterRule(panicRule, linter.Error)
+	l.RegisterRule(panicRule, linter.SeverityError)
 	issues, err := l.Lint(t.Context(), "devcontainer.json", []byte(`{}`), linter.Devcontainer)
 	if err != nil {
 		t.Fatalf("Lint: %v", err)
@@ -239,7 +239,7 @@ func TestLintRulePanicIsRecovered(t *testing.T) {
 	if issues[0].RuleID != "panic-rule" {
 		t.Errorf("RuleID = %q, want %q", issues[0].RuleID, "panic-rule")
 	}
-	if issues[0].Severity != linter.Error {
-		t.Errorf("Severity = %v, want %v", issues[0].Severity, linter.Error)
+	if issues[0].Severity != linter.SeverityError {
+		t.Errorf("Severity = %v, want %v", issues[0].Severity, linter.SeverityError)
 	}
 }

linter/rule.go

@@ -74,20 +74,20 @@ type Context struct {
 type Severity int
 
 const (
-	// Off disables a rule; it produces no findings.
-	Off Severity = iota
-	// Warn marks a finding as a warning.
-	Warn
-	// Error marks a finding as an error.
-	Error
+	// SeverityOff disables a rule; it produces no findings.
+	SeverityOff Severity = iota
+	// SeverityWarn marks a finding as a warning.
+	SeverityWarn
+	// SeverityError marks a finding as an error.
+	SeverityError
 )
 
 // String returns the severity's name, as used in output and configuration files.
 func (s Severity) String() string {
 	switch s {
-	case Error:
+	case SeverityError:
 		return "error"
-	case Warn:
+	case SeverityWarn:
 		return "warn"
 	default:
 		return "off"
@@ -123,11 +123,11 @@ func (s *Severity) UnmarshalJSONFrom(dec *jsontext.Decoder) error {
 func ParseSeverity(name string) (Severity, error) {
 	switch strings.ToLower(name) {
 	case "off":
-		return Off, nil
+		return SeverityOff, nil
 	case "warn":
-		return Warn, nil
+		return SeverityWarn, nil
 	case "error":
-		return Error, nil
+		return SeverityError, nil
 	default:
 		return 0, fmt.Errorf("unknown severity %q (want one of: off, warn, error)", name)
 	}

linter/rule_test.go

@@ -45,10 +45,10 @@ func TestParseSeverity(t *testing.T) {
 		want    linter.Severity
 		wantErr bool
 	}{
-		{"off", "off", linter.Off, false},
-		{"warn", "warn", linter.Warn, false},
-		{"error", "error", linter.Error, false},
-		{"mixed case", "Error", linter.Error, false},
+		{"off", "off", linter.SeverityOff, false},
+		{"warn", "warn", linter.SeverityWarn, false},
+		{"error", "error", linter.SeverityError, false},
+		{"mixed case", "Error", linter.SeverityError, false},
 		{"unknown", "bogus", 0, true},
 		{"empty", "", 0, true},
 	}
@@ -73,9 +73,9 @@ func TestSeverityJSON(t *testing.T) {
 		severity linter.Severity
 		want     string
 	}{
-		{linter.Off, `"off"`},
-		{linter.Warn, `"warn"`},
-		{linter.Error, `"error"`},
+		{linter.SeverityOff, `"off"`},
+		{linter.SeverityWarn, `"warn"`},
+		{linter.SeverityError, `"error"`},
 	}
 	for _, tt := range tests {
 		t.Run(tt.want, func(t *testing.T) {