From 801e7043d153f9e47aae556ae9e2553e8be01e96 Mon Sep 17 00:00:00 2001
From: Sylwester Piskozub <sylwesterpiskozub@gmail.com>
Date: Thu, 21 Aug 2025 15:59:03 +0200
Subject: [PATCH 1/2] enhance lint output

Signed-off-by: Sylwester Piskozub <sylwesterpiskozub@gmail.com>
---
 app/cli/internal/policydevel/lint.go | 66 +++++++++++++++++++++++++++-
 1 file changed, 64 insertions(+), 2 deletions(-)

diff --git a/app/cli/internal/policydevel/lint.go b/app/cli/internal/policydevel/lint.go
index 73eb655dd..862f0e72b 100644
--- a/app/cli/internal/policydevel/lint.go
+++ b/app/cli/internal/policydevel/lint.go
@@ -33,6 +33,7 @@ import (
 	"github.com/open-policy-agent/opa/v1/format"
 	"github.com/styrainc/regal/pkg/config"
 	"github.com/styrainc/regal/pkg/linter"
+	"github.com/styrainc/regal/pkg/report"
 	"github.com/styrainc/regal/pkg/rules"
 	"gopkg.in/yaml.v3"
 )
@@ -356,13 +357,39 @@ func (p *PolicyToLint) runRegalLinter(filePath, content string) {
 		return
 	}
 
-	// Add any violations to the policy errors
+	// Parse the Rego AST to map line numbers to rule names
+	regoRuleMap := p.buildRegoRuleMap(content)
+
+	// Add violations to the policy errors
 	for _, v := range report.Violations {
-		errorStr := strings.ReplaceAll(v.Description, "`opa fmt`", "`--format`")
+		errorStr := p.formatViolationError(v, regoRuleMap)
 		p.AddError(filePath, errorStr, v.Location.Row)
 	}
 }
 
+// Creates a formatted error message from a Regal violation
+// Follows format <file>:<line>: [<ruleName>] <errorMsg> - <docLinks>
+func (p *PolicyToLint) formatViolationError(v report.Violation, regoRuleMap map[int]string) string {
+	// Extract resources
+	var resources []string
+	for _, r := range v.RelatedResources {
+		resources = append(resources, r.Reference)
+	}
+	resourceStr := strings.Join(resources, ", ")
+
+	// Try to identify which Rego rule contains this violation
+	regoRuleName, exists := regoRuleMap[v.Location.Row]
+	if !exists {
+		regoRuleName = ""
+	} else {
+		regoRuleName = fmt.Sprintf("[%s]", regoRuleName)
+	}
+
+	// Format the error message
+	lintError := fmt.Sprintf("%s: %s - %s", regoRuleName, v.Description, resourceStr)
+	return strings.ReplaceAll(lintError, "`opa fmt`", "`--format`")
+}
+
 // Attempts to load configuration in this order:
 // 1. User-specified config
 // 2. Default config
@@ -465,3 +492,38 @@ func (p *PolicyToLint) updateEmbeddedRegoInYAML(file *File, rootNode *yaml.Node)
 
 	return nil
 }
+
+// Creates a mapping from line numbers to Rego rule names
+func (p *PolicyToLint) buildRegoRuleMap(regoSrc string) map[int]string {
+	ruleMap := make(map[int]string)
+
+	// Parse the Rego source into AST
+	module, err := opaAst.ParseModule("", regoSrc)
+	if err != nil {
+		return ruleMap // Return empty map if parsing fails
+	}
+
+	// Walk through the AST to find rule definitions
+	for _, rule := range module.Rules {
+		if rule.Location != nil {
+			ruleName := string(rule.Head.Name)
+			startLine := rule.Location.Row
+			endLine := startLine
+
+			// Try to find the end line of the rule
+			if rule.Body != nil && len(rule.Body) > 0 {
+				lastExpr := rule.Body[len(rule.Body)-1]
+				if lastExpr.Location != nil {
+					endLine = lastExpr.Location.Row
+				}
+			}
+
+			// Map all lines within this rule to the rule name
+			for line := startLine; line <= endLine; line++ {
+				ruleMap[line] = ruleName
+			}
+		}
+	}
+
+	return ruleMap
+}

From 358b00824f23d794d777a3e29119025d7197ca67 Mon Sep 17 00:00:00 2001
From: Sylwester Piskozub <sylwesterpiskozub@gmail.com>
Date: Thu, 21 Aug 2025 16:20:52 +0200
Subject: [PATCH 2/2] fix linter

Signed-off-by: Sylwester Piskozub <sylwesterpiskozub@gmail.com>
---
 app/cli/internal/policydevel/lint.go | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/app/cli/internal/policydevel/lint.go b/app/cli/internal/policydevel/lint.go
index 974e28154..fd37695ee 100644
--- a/app/cli/internal/policydevel/lint.go
+++ b/app/cli/internal/policydevel/lint.go
@@ -304,7 +304,7 @@ func (p *PolicyToLint) runRegalLinter(filePath, content string) {
 // Follows format <file>:<line>: [<ruleName>] <errorMsg> - <docLinks>
 func (p *PolicyToLint) formatViolationError(v report.Violation, regoRuleMap map[int]string) string {
 	// Extract resources
-	var resources []string
+	resources := make([]string, 0, len(v.RelatedResources))
 	for _, r := range v.RelatedResources {
 		resources = append(resources, r.Reference)
 	}
@@ -375,7 +375,8 @@ func (p *PolicyToLint) buildRegoRuleMap(regoSrc string) map[int]string {
 	// Parse the Rego source into AST
 	module, err := opaAst.ParseModule("", regoSrc)
 	if err != nil {
-		return ruleMap // Return empty map if parsing fails
+		// Return empty map if parsing fails
+		return ruleMap
 	}
 
 	// Walk through the AST to find rule definitions
@@ -386,7 +387,7 @@ func (p *PolicyToLint) buildRegoRuleMap(regoSrc string) map[int]string {
 			endLine := startLine
 
 			// Try to find the end line of the rule
-			if rule.Body != nil && len(rule.Body) > 0 {
+			if len(rule.Body) > 0 {
 				lastExpr := rule.Body[len(rule.Body)-1]
 				if lastExpr.Location != nil {
 					endLine = lastExpr.Location.Row