Tolerate empty compact options (#211)

While still producing an error. See #200
bufbuild · Dec 4, 2023 · ec8c634 · ec8c634
1 parent fc56311
commit ec8c634
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Showing 4 changed files with 458 additions and 401 deletions.
diff --git a/ast/options.go b/ast/options.go
@@ -335,10 +335,10 @@ func NewCompactOptionsNode(openBracket *RuneNode, opts []*OptionNode, commas []*
 	if closeBracket == nil {
 		panic("closeBracket is nil")
 	}
-	if len(opts) == 0 {
-		panic("must have at least one part")
+	if len(opts) == 0 && len(commas) != 0 {
+		panic("opts is empty but commas is not")
 	}
-	if len(commas) != len(opts)-1 {
+	if len(opts) > 0 && len(commas) != len(opts)-1 {
 		panic(fmt.Sprintf("%d opts requires %d commas, not %d", len(opts), len(opts)-1, len(commas)))
 	}
 	children := make([]Node, 0, len(opts)*2+1)

diff --git a/parser/parser_test.go b/parser/parser_test.go
@@ -127,6 +127,47 @@ func TestLenientParse_SemicolonLess(t *testing.T) {
 	}
 }
 
+func TestLenientParse_EmptyCompactOptions(t *testing.T) {
+	t.Parallel()
+	inputs := map[string]struct {
+		Error   string
+		NoError string
+	}{
+		"field-options": {
+			Error: `syntax = "proto3";
+							message Foo {
+								int32 bar = 1 [];
+							}`,
+			NoError: `syntax = "proto3";
+								message Foo {
+									int32 bar = 1 [default=1];
+								}`,
+		},
+		"enum-options": {
+			Error: `syntax = "proto3";
+							enum Foo {
+								FOO = 0 [];
+							}`,
+			NoError: `syntax = "proto3";
+								enum Foo {
+									FOO = 0 [deprecated=true];
+								}`,
+		},
+	}
+	for name, input := range inputs {
+		name, input := name, input
+		t.Run(name, func(t *testing.T) {
+			t.Parallel()
+			errHandler := reporter.NewHandler(nil)
+			protoName := fmt.Sprintf("%s.proto", name)
+			_, err := Parse(protoName, strings.NewReader(input.NoError), errHandler)
+			require.NoError(t, err)
+			_, err = Parse(protoName, strings.NewReader(input.Error), errHandler)
+			require.ErrorContains(t, err, "compact options must have at least one option")
+		})
+	}
+}
+
 func TestSimpleParse(t *testing.T) {
 	t.Parallel()
 	protos := map[string]Result{}

diff --git a/parser/proto.y b/parser/proto.y
@@ -598,6 +598,10 @@ fieldCardinality : _REQUIRED
 compactOptions: '[' compactOptionDecls ']' {
 		$$ = ast.NewCompactOptionsNode($1, $2.options, $2.commas, $3)
 	}
+	| '[' ']' {
+		protolex.(*protoLex).Error("compact options must have at least one option")
+		$$ = ast.NewCompactOptionsNode($1, nil, nil, $2)
+	}
 
 compactOptionDecls : compactOption {
 		$$ = &compactOptionSlices{options: []*ast.OptionNode{$1}}