feat(tmplexec): add feature flag to control error enrichment in debug mode for better traceability and cleaner output

pkg/tmplexec/exec.go

@@ -217,7 +217,7 @@ func (e *TemplateExecuter) Execute(ctx *scan.ScanContext) (bool, error) {
 		lastMatcherEvent.Lock()
 		defer lastMatcherEvent.Unlock()
 
-		lastMatcherEvent.InternalEvent["error"] = getErrorCause(ctx.GenerateErrorMessage())
+		lastMatcherEvent.InternalEvent["error"] = getErrorCause(ctx.GenerateErrorMessage(), e.options.Options.Debug)
 
 		writeFailureCallback(lastMatcherEvent, e.options.Options.MatcherStatus)
 	}
@@ -233,7 +233,7 @@ func (e *TemplateExecuter) Execute(ctx *scan.ScanContext) (bool, error) {
 					Info:       e.options.TemplateInfo,
 					Type:       e.getTemplateType(),
 					Host:       ctx.Input.MetaInput.Input,
-					Error:      getErrorCause(ctx.GenerateErrorMessage()),
+					Error:      getErrorCause(ctx.GenerateErrorMessage(), e.options.Options.Debug),
 				},
 			},
 			OperatorsResult: &operators.Result{
@@ -249,10 +249,13 @@ func (e *TemplateExecuter) Execute(ctx *scan.ScanContext) (bool, error) {
 // getErrorCause tries to parse the cause of given error
 // this is legacy support due to use of errorutil in existing libraries
 // but this should not be required once all libraries are updated
-func getErrorCause(err error) string {
+// debugMode controls whether to enrich errors with stack traces
+func getErrorCause(err error, debugMode bool) string {
 	if err == nil {
 		return ""
 	}
+
+	if debugMode {
 		errx := errkit.FromError(err)
 		var cause error
 		for _, e := range errx.Errors() {
@@ -265,8 +268,11 @@ func getErrorCause(err error) string {
 		if cause == nil {
 			cause = errkit.Append(errkit.New("could not get error cause"), errx)
 		}
-	// parseScanError prettifies the error message and removes everything except the cause
-	return parseScanError(cause.Error())
+		// parseScanErrorWithDebug prettifies the error message and removes everything except the cause
+		return parseScanErrorWithDebug(cause.Error(), debugMode)
+	}
+
+	return parseScanErrorWithDebug(err.Error(), debugMode)
 }
 
 // ExecuteWithResults executes the protocol requests and returns results instead of writing them.

pkg/tmplexec/exec_test.go

@@ -0,0 +1,184 @@
+package tmplexec
+
+import (
+	"errors"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetErrorCause_DebugMode(t *testing.T) {
+	testCases := []struct {
+		name        string
+		err         error
+		debugMode   bool
+		expectTrace bool
+		description string
+	}{
+		{
+			name:        "Debug mode enabled - should enrich error",
+			err:         errors.New("malformed request specified: GET /file=>"),
+			debugMode:   true,
+			expectTrace: true,
+			description: "When debug mode is enabled, errors should be enriched with additional context",
+		},
+		{
+			name:        "Debug mode disabled - should not enrich error",
+			err:         errors.New("malformed request specified: GET /file=>"),
+			debugMode:   false,
+			expectTrace: false,
+			description: "When debug mode is disabled, errors should not be enriched to avoid stack traces",
+		},
+		{
+			name:        "Nil error - debug mode enabled",
+			err:         nil,
+			debugMode:   true,
+			expectTrace: false,
+			description: "Nil errors should return empty string regardless of debug mode",
+		},
+		{
+			name:        "Nil error - debug mode disabled",
+			err:         nil,
+			debugMode:   false,
+			expectTrace: false,
+			description: "Nil errors should return empty string regardless of debug mode",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := getErrorCause(tc.err, tc.debugMode)
+
+			if tc.err == nil {
+				assert.Empty(t, result, "Expected empty string for nil error")
+				return
+			}
+
+			// Basic validation - result should contain the original error message
+			assert.Contains(t, result, "malformed request specified",
+				"Result should contain the original error message")
+
+			if tc.debugMode {
+				// In debug mode, we expect the error to be processed through errkit
+				// This doesn't necessarily mean stack traces in the final result,
+				// but ensures the error went through the enrichment path
+				assert.NotEmpty(t, result, "Debug mode should produce non-empty result")
+			} else {
+				// In non-debug mode, we should get a simple error message
+				// without any stack trace information
+				assert.NotContains(t, result, "Stacktrace:",
+					"Non-debug mode should not contain stack trace")
+				assert.NotContains(t, result, "goroutine",
+					"Non-debug mode should not contain goroutine information")
+				assert.NotContains(t, result, "runtime/debug.Stack()",
+					"Non-debug mode should not contain runtime stack information")
+			}
+		})
+	}
+}
+
+func TestParseScanErrorWithDebug(t *testing.T) {
+	testCases := []struct {
+		name      string
+		msg       string
+		debugMode bool
+		expected  string
+	}{
+		{
+			name:      "Simple error - debug mode off",
+			msg:       "connection refused",
+			debugMode: false,
+			expected:  "connection refused",
+		},
+		{
+			name:      "Simple error - debug mode on",
+			msg:       "connection refused",
+			debugMode: true,
+			expected:  "connection refused",
+		},
+		{
+			name:      "ReadStatusLine error - debug mode off",
+			msg:       "ReadStatusLine: malformed HTTP response",
+			debugMode: false,
+			expected:  "malformed HTTP response",
+		},
+		{
+			name:      "Empty message",
+			msg:       "",
+			debugMode: false,
+			expected:  "",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := parseScanErrorWithDebug(tc.msg, tc.debugMode)
+			assert.Contains(t, result, tc.expected,
+				"Result should contain expected error message")
+		})
+	}
+}
+
+func TestGetErrorCause_ContextDeadlineHandling(t *testing.T) {
+	testCases := []struct {
+		name      string
+		err       error
+		debugMode bool
+	}{
+		{
+			name:      "Context deadline exceeded - debug mode",
+			err:       errors.New("context deadline exceeded"),
+			debugMode: true,
+		},
+		{
+			name:      "Context deadline exceeded - non-debug mode",
+			err:       errors.New("context deadline exceeded"),
+			debugMode: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			result := getErrorCause(tc.err, tc.debugMode)
+			assert.NotEmpty(t, result, "Should handle context deadline exceeded errors")
+		})
+	}
+}
+
+func TestGetErrorCause_ErrorMessageFormat(t *testing.T) {
+	originalError := errors.New("test error message")
+
+	debugResult := getErrorCause(originalError, true)
+	nonDebugResult := getErrorCause(originalError, false)
+
+	// Both should contain the original error message
+	assert.Contains(t, debugResult, "test error message",
+		"Debug result should contain original error message")
+	assert.Contains(t, nonDebugResult, "test error message",
+		"Non-debug result should contain original error message")
+
+	// Non-debug should be simpler (no enrichment artifacts)
+	assert.True(t, len(nonDebugResult) <= len(debugResult) ||
+		strings.Count(nonDebugResult, "\n") <= strings.Count(debugResult, "\n"),
+		"Non-debug result should be simpler than debug result")
+}
+
+// Benchmark to ensure the non-debug path is more efficient
+func BenchmarkGetErrorCause_Debug(b *testing.B) {
+	err := errors.New("benchmark test error")
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		getErrorCause(err, true)
+	}
+}
+
+func BenchmarkGetErrorCause_NonDebug(b *testing.B) {
+	err := errors.New("benchmark test error")
+	b.ResetTimer()
+
+	for i := 0; i < b.N; i++ {
+		getErrorCause(err, false)
+	}
+}

pkg/tmplexec/interface.go

@@ -42,9 +42,8 @@ var (
 	reNoKind = regexp.MustCompile(`([\[][^][]+[\]]|errKind=[^ ]+) `)
 )
 
-// parseScanError parses given scan error and only returning the cause
-// instead of inefficient one
-func parseScanError(msg string) string {
+// parseScanErrorWithDebug processes error messages with optional debug mode
+func parseScanErrorWithDebug(msg string, debugMode bool) string {
 	if msg == "" {
 		return ""
 	}
@@ -58,6 +57,8 @@ func parseScanError(msg string) string {
 		parts := strings.Split(msg, ":")
 		msg = strings.TrimSpace(parts[len(parts)-1])
 	}
+
+	if debugMode {
 		e := errkit.FromError(errors.New(msg))
 		for _, err := range e.Errors() {
 			if err != nil && strings.Contains(err.Error(), "context deadline exceeded") {
@@ -69,3 +70,6 @@ func parseScanError(msg string) string {
 		wrapped := errkit.Append(errkit.New("failed to get error cause"), e).Error()
 		return reNoKind.ReplaceAllString(wrapped, "")
 	}
+
+	return reNoKind.ReplaceAllString(msg, "")
+}