encoding/protobuf: fix trailing comment in oneof bug

Fixes #586

Change-Id: I8281e90946e6de92bbf2f5819abcb48259128f48
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/7661
Reviewed-by: CUE cueckoo <[email protected]>
Reviewed-by: Marcel van Lohuizen <[email protected]>

Author: mpvl

encoding/protobuf/parse.go

@@ -676,21 +676,30 @@ func (p *protoConverter) oneOf(x *proto.Oneof) {
 
 	p.addDecl(embed)
 
-	for _, v := range x.Elements {
-		s := &ast.StructLit{
+	newStruct := func() {
+		s = &ast.StructLit{
 			// TODO: make this the default in the formatter.
 			Rbrace: token.Newline.Pos(),
 		}
+		embed.Expr = ast.NewBinExpr(token.OR, embed.Expr, s)
+	}
+	for _, v := range x.Elements {
 		switch x := v.(type) {
 		case *proto.OneOfField:
+			newStruct()
 			oneOf := p.parseField(s, 0, x.Field)
 			oneOf.Optional = token.NoPos
 
+		case *proto.Comment:
+			cg := comment(x, false)
+			ast.SetRelPos(cg, token.NewSection)
+			s.Elts = append(s.Elts, cg)
+
 		default:
+			newStruct()
 			p.messageField(s, 1, v)
 		}
 
-		embed.Expr = ast.NewBinExpr(token.OR, embed.Expr, s)
 	}
 }
 

encoding/protobuf/protobuf_test.go

@@ -38,6 +38,7 @@ func TestExtractDefinitions(t *testing.T) {
 		"networking/v1alpha3/gateway.proto",
 		"mixer/v1/attributes.proto",
 		"mixer/v1/config/client/client_config.proto",
+		"other/trailcomment.proto",
 	}
 	for _, file := range testCases {
 		t.Run(file, func(t *testing.T) {

encoding/protobuf/testdata/istio.io/api/other/trailcomment.proto

@@ -0,0 +1,15 @@
+// Issue #586
+package foo
+
+message Bar {
+    oneof Foo {
+        string a = 1;
+        // hello world
+
+        string b = 2;
+        // hello world
+    }
+
+    int32 c = 3;
+    // hello world
+}

encoding/protobuf/testdata/trailcomment.proto.out.cue

@@ -0,0 +1,20 @@
+// Issue #586
+package foo
+
+#Bar: {
+	{} | {
+		a: string @protobuf(1)
+
+		// hello world
+
+	} | {
+		b: string @protobuf(2)
+
+		// hello world
+
+	}
+	c?: int32 @protobuf(3)
+
+	// hello world
+
+}