[jira] [Assigned] (AVRO-1350) Error in decoding enums using ResolvingDecoder

["Thiruvalluvan M. G. (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AVRO-1350?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Thiruvalluvan M. G. reassigned AVRO-1350:
-----------------------------------------

    Assignee: Thiruvalluvan M. G.

> Error in decoding enums using ResolvingDecoder
> ----------------------------------------------
>
>                 Key: AVRO-1350
>                 URL: https://issues.apache.org/jira/browse/AVRO-1350
>             Project: Apache Avro
>          Issue Type: Bug
>          Components: c++
>    Affects Versions: 1.7.4
>            Reporter: Bin Guo
>            Assignee: Thiruvalluvan M. G.
>            Priority: Major
>
> We can't get a correct result when decoding enums using resolving decoder.  e.g.
> {code:title=schema}
> {
>   "type" : "record",
>   "name" : "TestEnum",
>   "fields" : [
> 	{
> 	    "name" : "MyMode",
> 	    "type" : {
> 	      "type" : "enum",
> 	      "name" : "Mode",
> 	      "symbols" : [ "MEMORY", "DISK" ]
> 	    }
> 	}
>   ]
> }
> {code}
> We encoded "DISK"(1), then decoded with resolving decoder, got "MEMORY"(0).
> I examined the code and found that there is a *sort* after reading names of reader.
> I could't quite understand the author's intention, but it really can not work well.
> When decoding my enum, the return value is actually the *position of the sorted names*, and obviously it's not correct.
> {code:title=Symbol.cc}
> Symbol Symbol::enumAdjustSymbol(const NodePtr& writer, const NodePtr& reader)
> {
>     vector<string> rs;
>     size_t rc = reader->names();
>     for (size_t i = 0; i < rc; ++i) {
>         rs.push_back(reader->nameAt(i));
>     }
>     sort(rs.begin(), rs.end()); // the strange sort
> {code}
> Here is my complete test case.
> {code:title=generated structure}
> enum Mode {
>     MEMORY,
>     DISK,
> };
> struct TestEnum {
>     Mode MyMode;
> };
> {code}
> {code:title=My test case}
> #include "ts_enum.h"
> #include "avro/Compiler.hh"
> #include "avro/ValidSchema.hh"
> using namespace std;
> using namespace avro;
> using namespace enum_test;
> static const char ts_schema_string[] =
>         "{ \"type\" : \"record\", \"name\" : \"TestEnum\", \"fields\" : "
>         "[ { \"name\" : \"MyMode\", \"type\" : "
>         "{ \"type\" : \"enum\", \"name\" : \"Mode\", "
>         "\"symbols\" : [ \"MEMORY\", \"DISK\" ] } } ]}";
> int main(int argc, char * argv[]) {
>     TestEnum te1, te2;
>     ValidSchema reader = compileJsonSchemaFromString(ts_schema_string);
>     ValidSchema writer = compileJsonSchemaFromString(ts_schema_string);
>     //encode TestEnum
>     auto_ptr<OutputStream> out_stream = memoryOutputStream();
>     EncoderPtr encoder = binaryEncoder();
>     encoder->init(*out_stream);
>     te1.MyMode = DISK;
>     encode(*encoder, te1);
>     encoder->flush();
>     //decode TestEnum
>     auto_ptr<InputStream> in_stream = memoryInputStream(*out_stream);
>     DecoderPtr decoder = resolvingDecoder(writer, reader, avro::binaryDecoder());
>     decoder->init(*in_stream);
>     decode(*decoder, te2);
>     cout<<"TE1: "<<te1.MyMode << " | TE2: "<<te2.MyMode<<endl;
>     return 0;
> }
> {code}
> The result
> -------------------
> TE1: 1 | TE2: 0
> I debuged into avro code. 
> In Symbol::enumAdjustSymbol, there is a vector<string> of reader's enum names, and after the sort, "MEMOEY, DISK" turned to be "DISK, MEMORY". 
> At last, a vector<int> of writer's enum names saved every position of the sorted vector<string>. 
> As a result, in the returned symbol, MEMORY's position is 1 and DISK's position is 0. 
> Finally, when we decoding the enum, the *position* is returned to the target object.
> I could't quite understand the author's intention here but when I commented the sort, everything worked well.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)