Merge pull request #97 from yoheimuta/yoheimuta/issue96

Fix parsing error in buf validate proto file

Author: yoheimuta

parser/reserved.go

@@ -163,6 +163,9 @@ func (p *Parser) parseRange() (*Range, error) {
 
 // fieldNames = fieldName { "," fieldName }
 // See https://developers.google.com/protocol-buffers/docs/reference/proto3-spec#reserved
+// Note: While the spec requires commas between field names, this parser also supports
+// field names separated by whitespace without commas, which is not mentioned in the spec
+// but is supported by protoc and other parsers.
 func (p *Parser) parseFieldNames() ([]string, error) {
 	var fieldNames []string
 
@@ -173,17 +176,29 @@ func (p *Parser) parseFieldNames() ([]string, error) {
 	fieldNames = append(fieldNames, fieldName)
 
 	for {
+		// Check if next token is a comma
 		p.lex.Next()
-		if p.lex.Token != scanner.TCOMMA {
+		if p.lex.Token == scanner.TCOMMA {
+			// If it's a comma, parse the next field name
+			fieldName, err = p.parseFieldName()
+			if err != nil {
+				return nil, err
+			}
+			fieldNames = append(fieldNames, fieldName)
+		} else {
+			// If it's not a comma, put it back and try to parse another field name
 			p.lex.UnNext()
-			break
-		}
 
-		fieldName, err = p.parseFieldName()
-		if err != nil {
-			return nil, err
+			// Try to parse another field name
+			nextFieldName, err := p.parseFieldName()
+			if err != nil {
+				// If parsing fails, we're done with field names
+				break
+			}
+
+			// Successfully parsed another field name
+			fieldNames = append(fieldNames, nextFieldName)
 		}
-		fieldNames = append(fieldNames, fieldName)
 	}
 	return fieldNames, nil
 }

parser/reserved_test.go

@@ -130,6 +130,57 @@ func TestParser_ParseReserved(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "parsing field names on separate lines without commas. See #96",
+			input: `reserved
+	"skipped"
+	"ignore_empty"
+;`,
+			wantReserved: &parser.Reserved{
+				FieldNames: []string{
+					`"skipped"`,
+					`"ignore_empty"`,
+				},
+				Meta: meta.Meta{
+					Pos: meta.Position{
+						Offset: 0,
+						Line:   1,
+						Column: 1,
+					},
+					LastPos: meta.Position{
+						Offset: 36,
+						Line:   4,
+						Column: 1,
+					},
+				},
+			},
+		},
+		{
+			name: "parsing a mix of comma-separated and whitespace-separated field names",
+			input: `reserved "field1", 
+	"field2"
+	"field3", "field4";`,
+			wantReserved: &parser.Reserved{
+				FieldNames: []string{
+					`"field1"`,
+					`"field2"`,
+					`"field3"`,
+					`"field4"`,
+				},
+				Meta: meta.Meta{
+					Pos: meta.Position{
+						Offset: 0,
+						Line:   1,
+						Column: 1,
+					},
+					LastPos: meta.Position{
+						Offset: 49,
+						Line:   3,
+						Column: 20,
+					},
+				},
+			},
+		},
 	}
 
 	for _, test := range tests {