[Bug]: Mismatch in single-precision float encoding between Java and Go RowCoder implementations

[TheNeuralBit]

What happened?

Java uses FloatCoder for encoding the FLOAT type, which encodes as a 4 byte single-precision floating point number. Go currently shunts FLOAT through the same path as DOUBLE:

beam/sdks/go/pkg/beam/core/graph/coder/row_encoder.go

Lines 211 to 214 in cc0b446

	case reflect.Float32, reflect.Float64:
	return typeEncoderFieldReflect{encode: func(rv reflect.Value, w io.Writer) error {
	return EncodeDouble(rv.Float(), w)
	}}, nil

I've currently proposed to make the Python implementation the same as Java: #22626

I think we should do this in Go as well.

Issue Priority

Priority: 2

Issue Component

Component: sdk-go

[TheNeuralBit]

Re-opening this to track getting the standard_coders.yaml test passing

[TheNeuralBit]

Failure log when re-enabling the #22626 test:

ok      github.com/apache/beam/sdks/v2/go/test/regression       (cached)                                                                                                                                                                                       
2022/08/12 11:28:05 skipping unnested coder spec: {beam:coder:bytes:v1  [] false}                                                                                                                                                                              
2022/08/12 11:28:05 skipping unnested coder spec: {beam:coder:string_utf8:v1  [] false}                              
2022/08/12 11:28:05 skipping unnested coder spec: {beam:coder:kv:v1  [{beam:coder:bytes:v1  [] false} {beam:coder:bytes:v1  [] false}] false}
2022/08/12 11:28:05 skipping unimplemented coder urn: beam:coder:timer:v1                                           
2022/08/12 11:28:05 skipping unimplemented coder urn: beam:coder:param_windowed_value:v1                                                                                                                                                                       
2022/08/12 11:28:05 skipping unimplemented coder urn: beam:coder:param_windowed_value:v1
2022/08/12 11:28:05 skipping coder case. Unsupported in the Go SDK for now: https://github.com/apache/beam/issues/21206: Support encoding position. Payload: 
                                                               
                                                                                                                               
str(
                                                                                                                               
f_boo(

                                                               
i3$30ea5a25-dcd8-4cdb-abeb-5332d15ab4b9 
2022/08/12 11:28:05 skipping coder case. Unsupported in the Go SDK for now: BEAM-9615: Support logical types Payload: 

                                                               
f_timestampp:n                              
#beam:logical_type:micros_instant:v1G2E                     
C
                                                               
seconds                                               
                                                               
                                                               
micros$4d3f6e8f-7412-4ad7-bfd9-b424a1664aef
                                                               
f_string
                                                               
                                                               
f_int$33dafd37-397c-4083-a84e-42177d122221
2022/08/12 11:28:05 skipping unimplemented coder urn: beam:coder:sharded_key:v1                                                                                                                                                                                
2022/08/12 11:28:05 skipping unimplemented test coverage for beam:coder:state_backed_iterable:v1. https://github.com/apache/beam/issues/21324
2022/08/12 11:28:05 skipping unimplemented test coverage for beam:coder:state_backed_iterable:v1. https://github.com/apache/beam/issues/21324
2022/08/12 11:28:05 skipping unimplemented test coverage for beam:coder:state_backed_iterable:v1. https://github.com/apache/beam/issues/21324
2022/08/12 11:28:05 skipping unimplemented test coverage for beam:coder:state_backed_iterable:v1. https://github.com/apache/beam/issues/21324
2022/08/12 11:28:05 skipping unimplemented test coverage for beam:coder:state_backed_iterable:v1. https://github.com/apache/beam/issues/21324
2022/08/12 11:28:05 skipping unimplemented test coverage for beam:coder:state_backed_iterable:v1. https://github.com/apache/beam/issues/21324
2022/08/12 11:28:05 skipping unimplemented coder urn: beam:coder:custom_window:v1
--- FAIL: TestStandardCoders (0.00s)
    --- FAIL: TestStandardCoders/beam:coder:row:v1#06 (0.00s)
        fromyaml_test.go:42: Failed "{beam:coder:row:v1 
             
            f_float$8c97b6c5-69e5-4733-907b-26cd8edae612 [] false}": panicked on coder R;0[struct { F_float float32 "beam:\"f_float\"" }] || {beam:coder:row:v1 
             
            f_float$8c97b6c5-69e5-4733-907b-26cd8edae612 [] false}:
                reflect.StructOf: field 0 has no type :
            goroutine 39 [running]:
            runtime/debug.Stack()
                /usr/local/google/home/bhulette/sdk/go1.18.1/src/runtime/debug/stack.go:24 +0x65
            github.com/apache/beam/sdks/v2/go/test/regression/coders/fromyaml.(*Spec).testStandardCoder.func1()
                /usr/local/google/home/bhulette/working_dir/beam/sdks/go/test/regression/coders/fromyaml/fromyaml.go:124 +0x66
            panic({0x965640, 0xc0003a8560})
                /usr/local/google/home/bhulette/sdk/go1.18.1/src/runtime/panic.go:838 +0x207
            reflect.StructOf({0xc0003b62a0, 0x1, 0xc0000e9770?})
                /usr/local/google/home/bhulette/sdk/go1.18.1/src/reflect/type.go:2457 +0x2899
            github.com/apache/beam/sdks/v2/go/test/regression/coders/fromyaml.diff({{0xc0000372d8, 0x11}, {0xc000380800, 0x35}, {0x0, 0x0, 0x0}, 0x0}, 0xc0003b6230, {{0x965640, ...}, ...})
                /usr/local/google/home/bhulette/working_dir/beam/sdks/go/test/regression/coders/fromyaml/fromyaml.go:317 +0x162c
            github.com/apache/beam/sdks/v2/go/test/regression/coders/fromyaml.(*Spec).testStandardCoder(0xc000375a80)
                /usr/local/google/home/bhulette/working_dir/beam/sdks/go/test/regression/coders/fromyaml/fromyaml.go:148 +0x8ad 
            github.com/apache/beam/sdks/v2/go/test/regression/coders/fromyaml.TestStandardCoders.func1(0xc0003ac1a0)
                /usr/local/google/home/bhulette/working_dir/beam/sdks/go/test/regression/coders/fromyaml/fromyaml_test.go:41 +0x2e
            testing.tRunner(0xc0003ac1a0, 0xc0003a8490)
                /usr/local/google/home/bhulette/sdk/go1.18.1/src/testing/testing.go:1439 +0x102
            created by testing.(*T).Run
                /usr/local/google/home/bhulette/sdk/go1.18.1/src/testing/testing.go:1486 +0x35f
FAIL
FAIL    github.com/apache/beam/sdks/v2/go/test/regression/coders/fromyaml       0.054s
FAIL

> Task :sdks:go:goTest FAILED

[lostluck]

Ah whoops. The problem is that there are two separate parts for Row Coding: actually encoding from the Go structs (which Jacks PR did) and converting those struct types to the schema proto representation. The latter should be what's missing, under graphx.