fix: return an error for unterminated template comments

comments_test.go

@@ -28,6 +28,12 @@ func Test_Comment(t *testing.T) {
 	}
 }
 
+func Test_Unterminated_Comment(t *testing.T) {
+	output, err := plush.Render("<%# unterminated comment", plush.NewContext())
+	require.EqualError(t, err, "line 1: unterminated comment")
+	require.Empty(t, output)
+}
+
 func Test_Block_Comment(t *testing.T) {
 	r := require.New(t)
 	input := map[string]string{

parser/comments_test.go

@@ -0,0 +1,32 @@
+package parser_test
+
+import (
+	"testing"
+
+	"github.com/gobuffalo/plush/v5/parser"
+	"github.com/stretchr/testify/require"
+)
+
+func Test_Unterminated_Comment(t *testing.T) {
+	tests := []struct {
+		name  string
+		input string
+		err   string
+	}{
+		{"empty", "<%#", "line 1: unterminated comment"},
+		{"text", "<%# comment", "line 1: unterminated comment"},
+		{"partial closing tag", "<%# comment %", "line 1: unterminated comment"},
+		{"multiline", "<%# first line\nsecond line", "line 2: unterminated comment"},
+		{"trailing newline", "<%#\n", "line 2: unterminated comment"},
+		{"after HTML", "Hello\n<%# comment", "line 2: unterminated comment"},
+		{"inside code", "<% <%# comment", "line 1: unterminated comment"},
+		{"after closed comment", "<%# closed %><%#", "line 1: unterminated comment"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := parser.Parse(tt.input)
+			require.EqualError(t, err, tt.err)
+		})
+	}
+}

parser/parser.go

@@ -374,6 +374,11 @@ func (p *parser) parseStringLiteral() ast.Expression {
 
 func (p *parser) parseCommentLiteral() ast.Expression {
 	for p.curToken.Type != token.E_END {
+		if p.curTokenIs(token.EOF) {
+			msg := fmt.Sprintf("line %d: unterminated comment", p.curToken.LineNumber)
+			p.errors = append(p.errors, msg)
+			return nil
+		}
 		p.nextToken()
 	}
 

vm/plush/parity_errors_test.go

@@ -118,6 +118,8 @@ func Test_Parity_Phase_13_Line_Numbers(t *testing.T) {
 }
 
 func Test_Parity_Phase_13_Parser_And_EOF_Syntax_Errors(t *testing.T) {
+	compareExactRenderError(t, `<%#`, emptyContext)
+	compareExactRenderError(t, "<%# first line\nsecond line", emptyContext)
 	compareExactRenderError(t, `<% let = %>`, emptyContext)
 	compareBothRenderError(t, `<%= if true %>bad<% } %>`, emptyContext)
 	compareBothRenderError(t, `<%= foo("unterminated) %>`, contextWith(map[string]interface{}{