CODEWITHSUNDEEP
schemaflatbuffers
Stefan F.
Stefan F.

Reputation: 151

Flatbuffers Schema: Vectors of unions not possible with --binary

I get this error when trying to use vectors of unions and generating wire format binaries (--binary)

flatc.exe --cpp --java --js --csharp --binary c.fbs
error: D:\FlatbuffersVectorOfUnions\c.fbs(13, 9): error: Vectors of unions are not yet supported in all the specified programming languages.

Without the --binary-switch flatc.exe doesn't complain:

flatc.exe --cpp --java --js --csharp c.fbs

Is it really not possible to use vectors of unions when generating wire format binaries? I thought this is the binary serialisation of the textual schema and should support everything which is possible with the .fbs files.

I was curious and changed Parser::SupportsVectorOfUnions() in idl_parser.cpp (| IDLOptions::kBinary) and it seems to work.

bool Parser::SupportsVectorOfUnions() const {
  return opts.lang_to_generate != 0 &&
         (opts.lang_to_generate & ~(IDLOptions::kCpp | IDLOptions::kJs |
                                    IDLOptions::kTs | IDLOptions::kPhp |
                                    IDLOptions::kJava | IDLOptions::kCSharp | IDLOptions::kBinary)) == 0;
}

This is the c.fbs

table A {
}

table B {
}

union U {
    A,
    B
}

table C {
    v : [U];
}

root_type C;

Upvotes: 0

Views: 429

Answers (1)

user12347772
user12347772

Reputation: 21

This has already been fixed in the master branch. Parser::SupportsAdvancedUnionFeatures() in the current version of idl_parser.cpp supports kBinary:

bool Parser::SupportsAdvancedUnionFeatures() const {   return opts.lang_to_generate != 0 &&
         (opts.lang_to_generate &
          ~(IDLOptions::kCpp | IDLOptions::kJs | IDLOptions::kTs |
            IDLOptions::kPhp | IDLOptions::kJava | IDLOptions::kCSharp |
            IDLOptions::kKotlin | IDLOptions::kBinary)) == 0; }

Upvotes: 2

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