Tolerate missing ';' after package, imports, file options, and method options (bufbuild#212)

While still producing an error. See
bufbuild#200

Author: Alfus

ast/file.go

@@ -275,10 +275,10 @@ func NewImportNode(keyword *KeywordNode, public *KeywordNode, weak *KeywordNode,
 	if name == nil {
 		panic("name is nil")
 	}
+	numChildren := 2
 	if semicolon == nil {
-		panic("semicolon is nil")
+		numChildren++
 	}
-	numChildren := 3
 	if public != nil || weak != nil {
 		numChildren++
 	}
@@ -289,7 +289,10 @@ func NewImportNode(keyword *KeywordNode, public *KeywordNode, weak *KeywordNode,
 	} else if weak != nil {
 		children = append(children, weak)
 	}
-	children = append(children, name, semicolon)
+	children = append(children, name)
+	if semicolon != nil {
+		children = append(children, semicolon)
+	}
 
 	return &ImportNode{
 		compositeNode: compositeNode{
@@ -328,10 +331,12 @@ func NewPackageNode(keyword *KeywordNode, name IdentValueNode, semicolon *RuneNo
 	if name == nil {
 		panic("name is nil")
 	}
+	var children []Node
 	if semicolon == nil {
-		panic("semicolon is nil")
+		children = []Node{keyword, name}
+	} else {
+		children = []Node{keyword, name, semicolon}
 	}
-	children := []Node{keyword, name, semicolon}
 	return &PackageNode{
 		compositeNode: compositeNode{
 			children: children,

parser/ast.go

@@ -108,6 +108,24 @@ func newServiceElements(semicolons []*ast.RuneNode, elements []ast.ServiceElemen
 	return elems
 }
 
+func newMethodElements(semicolons []*ast.RuneNode, elements []ast.RPCElement) []ast.RPCElement {
+	elems := make([]ast.RPCElement, 0, len(semicolons)+len(elements))
+	for _, semicolon := range semicolons {
+		elems = append(elems, ast.NewEmptyDeclNode(semicolon))
+	}
+	elems = append(elems, elements...)
+	return elems
+}
+
+func newFileElements(semicolons []*ast.RuneNode, elements []ast.FileElement) []ast.FileElement {
+	elems := make([]ast.FileElement, 0, len(semicolons)+len(elements))
+	for _, semicolon := range semicolons {
+		elems = append(elems, ast.NewEmptyDeclNode(semicolon))
+	}
+	elems = append(elems, elements...)
+	return elems
+}
+
 type nodeWithEmptyDecls[T ast.Node] struct {
 	Node       T
 	EmptyDecls []*ast.EmptyDeclNode
@@ -121,10 +139,28 @@ func newNodeWithEmptyDecls[T ast.Node](node T, extraSemicolons []*ast.RuneNode)
 }
 
 func toServiceElements[T ast.ServiceElement](nodes nodeWithEmptyDecls[T]) []ast.ServiceElement {
-	serviceElements := make([]ast.ServiceElement, 1+len(nodes.EmptyDecls))
-	serviceElements[0] = nodes.Node
+	elements := make([]ast.ServiceElement, 1+len(nodes.EmptyDecls))
+	elements[0] = nodes.Node
+	for i, emptyDecl := range nodes.EmptyDecls {
+		elements[i+1] = emptyDecl
+	}
+	return elements
+}
+
+func toMethodElements[T ast.RPCElement](nodes nodeWithEmptyDecls[T]) []ast.RPCElement {
+	elements := make([]ast.RPCElement, 1+len(nodes.EmptyDecls))
+	elements[0] = nodes.Node
+	for i, emptyDecl := range nodes.EmptyDecls {
+		elements[i+1] = emptyDecl
+	}
+	return elements
+}
+
+func toFileElements[T ast.FileElement](nodes nodeWithEmptyDecls[T]) []ast.FileElement {
+	elements := make([]ast.FileElement, 1+len(nodes.EmptyDecls))
+	elements[0] = nodes.Node
 	for i, emptyDecl := range nodes.EmptyDecls {
-		serviceElements[i+1] = emptyDecl
+		elements[i+1] = emptyDecl
 	}
-	return serviceElements
+	return elements
 }

parser/parser_test.go

@@ -88,6 +88,30 @@ func TestLenientParse_SemicolonLess(t *testing.T) {
 		Error   string
 		NoError string
 	}{
+		"package": {
+			Error: `syntax = "proto3";
+							package foo
+							message Foo {}`,
+			NoError: `syntax = "proto3";
+								package foo;
+								message Foo {};`,
+		},
+		"import": {
+			Error: `syntax = "proto3";
+							import "foo.proto"
+							message Foo {}`,
+			NoError: `syntax = "proto3";
+								import "foo.proto";;
+								message Foo {};`,
+		},
+		"file-options": {
+			Error: `syntax = "proto3";
+							option (foo) = 1
+							message Foo {}`,
+			NoError: `syntax = "proto3";
+								option (foo) = 1;;
+								message Foo {};`,
+		},
 		"method": {
 			Error: `syntax = "proto3";
 							service Foo {
@@ -112,6 +136,22 @@ func TestLenientParse_SemicolonLess(t *testing.T) {
 								  option (foo) = { bar: 1 };
 								}`,
 		},
+		"method-options": {
+			Error: `syntax = "proto3";
+							service Foo {
+								rpc Bar (Baz) returns (Qux) {
+									;
+									option (foo) = { bar: 1 }
+								}
+							}`,
+			NoError: `syntax = "proto3";
+								service Foo {
+									rpc Bar (Baz) returns (Qux) {
+										;
+										option (foo) = { bar: 1 };;
+									}
+								}`,
+		},
 	}
 	for name, input := range inputs {
 		name, input := name, input