chore: emit more reasonable error message when using incomplete type …

…in struct (google#7678) Co-authored-by: Derek Bailey <[email protected]>
sunwen18 · Dec 25, 2022 · 3eb45e5 · 3eb45e5
1 parent f7282a5
commit 3eb45e5
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diff --git a/include/flatbuffers/idl.h b/include/flatbuffers/idl.h
@@ -473,6 +473,10 @@ inline bool IsStruct(const Type &type) {
   return type.base_type == BASE_TYPE_STRUCT && type.struct_def->fixed;
 }
 
+inline bool IsIncompleteStruct(const Type &type) {
+  return type.base_type == BASE_TYPE_STRUCT && type.struct_def->predecl;
+}
+
 inline bool IsTable(const Type &type) {
   return type.base_type == BASE_TYPE_STRUCT && !type.struct_def->fixed;
 }

diff --git a/src/idl_parser.cpp b/src/idl_parser.cpp
@@ -918,6 +918,12 @@ CheckedError Parser::ParseField(StructDef &struct_def) {
   ECHECK(ParseType(type));
 
   if (struct_def.fixed) {
+    if (IsIncompleteStruct(type) || 
+        (IsArray(type) && IsIncompleteStruct(type.VectorType()))) {
+      std::string type_name = IsArray(type) ? type.VectorType().struct_def->name : type.struct_def->name;
+      return Error(std::string("Incomplete type in struct is not allowed, type name: ") + type_name);
+    }
+
     auto valid = IsScalar(type.base_type) || IsStruct(type);
     if (!valid && IsArray(type)) {
       const auto &elem_type = type.VectorType();