Optimistically match shellcheck errors to source

ast.go

@@ -40,6 +40,8 @@ type String struct {
 	Quoted bool
 	// Pos is a position of the string in source.
 	Pos *Pos
+	// If string is a literal block which preserves newlines and indentation. Helpful for error messages
+	Literal bool
 }
 
 // ContainsExpression checks if the given string contains a ${{ }} placeholder or not. This function

parse.go

@@ -38,7 +38,8 @@ func isNull(n *yaml.Node) bool {
 
 func newString(n *yaml.Node) *String {
 	quoted := n.Style&(yaml.DoubleQuotedStyle|yaml.SingleQuotedStyle) != 0
-	return &String{n.Value, quoted, posAt(n)}
+	literal := n.Style == yaml.LiteralStyle
+	return &String{n.Value, quoted, posAt(n), literal}
 }
 
 type workflowKeyVal struct {
@@ -137,7 +138,7 @@ func (p *parser) mayParseExpression(n *yaml.Node) *String {
 
 func (p *parser) parseString(n *yaml.Node, allowEmpty bool) *String {
 	if !p.checkString(n, allowEmpty) {
-		return &String{"", false, posAt(n)}
+		return &String{"", false, posAt(n), false}
 	}
 	return newString(n)
 }

rule_runner_label.go

@@ -266,7 +266,7 @@ func (rule *RuleRunnerLabel) tryToGetLabelsInMatrix(label *String, m *Matrix) []
 		if row, ok := m.Rows[prop]; ok {
 			for _, v := range row.Values {
 				if s, ok := v.(*RawYAMLString); ok && !ContainsExpression(s.Value) {
-					labels = append(labels, &String{s.Value, false, s.Pos()})
+					labels = append(labels, &String{s.Value, false, s.Pos(), false})
 				}
 			}
 		}
@@ -277,7 +277,7 @@ func (rule *RuleRunnerLabel) tryToGetLabelsInMatrix(label *String, m *Matrix) []
 			if combi.Assigns != nil {
 				if assign, ok := combi.Assigns[prop]; ok {
 					if s, ok := assign.Value.(*RawYAMLString); ok && !ContainsExpression(s.Value) {
-						labels = append(labels, &String{s.Value, false, s.Pos()})
+						labels = append(labels, &String{s.Value, false, s.Pos(), false})
 					}
 				}
 			}

rule_runner_label_test.go

@@ -255,7 +255,7 @@ func TestRuleRunnerLabelCheckLabels(t *testing.T) {
 			pos := &Pos{}
 			labels := make([]*String, 0, len(tc.labels))
 			for _, l := range tc.labels {
-				labels = append(labels, &String{l, false, pos})
+				labels = append(labels, &String{l, false, pos, false})
 			}
 			node := &Job{
 				RunsOn: &Runner{
@@ -264,7 +264,7 @@ func TestRuleRunnerLabelCheckLabels(t *testing.T) {
 			}
 
 			if tc.matrix != nil {
-				n := &String{"os", false, pos}
+				n := &String{"os", false, pos, false}
 				row := make([]RawYAMLValue, 0, len(tc.matrix))
 				for _, m := range tc.matrix {
 					row = append(row, &RawYAMLString{m, pos})

rule_shellcheck.go

@@ -3,6 +3,7 @@ package actionlint
 import (
 	"encoding/json"
 	"fmt"
+	"os"
 	"strings"
 	"sync"
 )
@@ -57,7 +58,7 @@ func (rule *RuleShellcheck) VisitStep(n *Step) error {
 		return nil
 	}
 
-	rule.runShellcheck(run.Run.Value, rule.getShellName(run), run.RunPos)
+	rule.runShellcheck(run.Run, rule.getShellName(run), run.RunPos)
 	return nil
 }
 
@@ -160,7 +161,7 @@ func sanitizeExpressionsInScript(src string) string {
 	}
 }
 
-func (rule *RuleShellcheck) runShellcheck(src, shell string, pos *Pos) {
+func (rule *RuleShellcheck) runShellcheck(srcAst *String, shell string, pos *Pos) {
 	var sh string
 	if shell == "bash" || shell == "sh" {
 		sh = shell
@@ -172,6 +173,7 @@ func (rule *RuleShellcheck) runShellcheck(src, shell string, pos *Pos) {
 		return // Skip checking this shell script since shellcheck doesn't support it
 	}
 
+	src := srcAst.Value
 	src = sanitizeExpressionsInScript(src)
 	rule.Debug("%s: Run shellcheck for %s script:\n%s", pos, sh, src)
 
@@ -214,6 +216,8 @@ func (rule *RuleShellcheck) runShellcheck(src, shell string, pos *Pos) {
 			return nil
 		}
 
+		rule.EnableDebug(os.Stdout)
+
 		// Synchronize rule.Errorf calls
 		rule.mu.Lock()
 		defer rule.mu.Unlock()
@@ -227,7 +231,14 @@ func (rule *RuleShellcheck) runShellcheck(src, shell string, pos *Pos) {
 			// Consider the first line is setup for running shell which was implicitly added for better check
 			line := err.Line - 1
 			msg := strings.TrimSuffix(err.Message, ".") // Trim period aligning style of error message
-			rule.Errorf(pos, "shellcheck reported issue in this script: SC%d:%s:%d:%d: %s", err.Code, err.Level, line, err.Column, msg)
+
+			var errorLocation Pos
+			if srcAst.Literal {
+				errorLocation = Pos{line + srcAst.Pos.Line, err.Column + srcAst.Pos.Col - 4}
+			} else {
+				errorLocation = *pos
+			}
+			rule.Errorf(&errorLocation, "shellcheck reported issue in this script: SC%d:%s:%d:%d: %s", err.Code, err.Level, line, err.Column, msg)
 		}
 
 		return nil