Repository: hamba/avro (go)

Issue:
Stack overflow on marshal with recursive types
Simple example of complex type avro spec:
https://avro.apache.org/docs/current/spec.html#schema_complex
Record has a reference to its own type.
On marshaling I get panic. 
Example code  in repo:
https://gitlab.com/nikulin.e/avro_test

Pull request description:
feat: support recursive types
This adds support for recursive types.

Fixes #138 

Patch:
diff --git a/codec.go b/codec.go
index cb83035..3553088 100644
--- a/codec.go
+++ b/codec.go
@@ -46,6 +46,10 @@ func (r *Reader) ReadVal(schema Schema, obj interface{}) {
 			r.ReportError("ReadVal", "can only unmarshal into pointer")
 			return
 		}
+		if typ.Kind() == reflect.Ptr {
+			ptrType := typ.(*reflect2.UnsafePtrType)
+			typ = ptrType.Elem()
+		}
 
 		decoder = r.cfg.DecoderOf(schema, typ)
 	}
@@ -79,9 +83,12 @@ func (c *frozenConfig) DecoderOf(schema Schema, typ reflect2.Type) ValDecoder {
 		return decoder
 	}
 
-	ptrType := typ.(*reflect2.UnsafePtrType)
-	decoder = decoderOfType(c, schema, ptrType.Elem())
+	pe := &placeholderEncoder{}
+	c.addDecoderToCache(schema.Fingerprint(), rtype, pe)
+
+	decoder = decoderOfType(c, schema, typ)
 	c.addDecoderToCache(schema.Fingerprint(), rtype, decoder)
+	pe.dec = decoder
 	return decoder
 }
 
@@ -139,14 +146,31 @@ func (c *frozenConfig) EncoderOf(schema Schema, typ reflect2.Type) ValEncoder {
 		return encoder
 	}
 
+	pe := &placeholderEncoder{}
+	c.addEncoderToCache(schema.Fingerprint(), rtype, pe)
+
 	encoder = encoderOfType(c, schema, typ)
 	if typ.LikePtr() {
 		encoder = &onePtrEncoder{encoder}
 	}
 	c.addEncoderToCache(schema.Fingerprint(), rtype, encoder)
+	pe.enc = encoder
 	return encoder
 }
 
+type placeholderEncoder struct {
+	enc ValEncoder
+	dec ValDecoder
+}
+
+func (e *placeholderEncoder) Encode(ptr unsafe.Pointer, w *Writer) {
+	e.enc.Encode(noescape(ptr), w)
+}
+
+func (e *placeholderEncoder) Decode(ptr unsafe.Pointer, r *Reader) {
+	e.dec.Decode(noescape(ptr), r)
+}
+
 type onePtrEncoder struct {
 	enc ValEncoder
 }
diff --git a/codec_array.go b/codec_array.go
index fe35e9d..a8d05c7 100644
--- a/codec_array.go
+++ b/codec_array.go
@@ -29,7 +29,7 @@ func createEncoderOfArray(cfg *frozenConfig, schema Schema, typ reflect2.Type) V
 func decoderOfArray(cfg *frozenConfig, schema Schema, typ reflect2.Type) ValDecoder {
 	arr := schema.(*ArraySchema)
 	sliceType := typ.(*reflect2.UnsafeSliceType)
-	decoder := decoderOfType(cfg, arr.Items(), sliceType.Elem())
+	decoder := cfg.DecoderOf(arr.Items(), sliceType.Elem())
 
 	return &arrayDecoder{typ: sliceType, decoder: decoder}
 }
@@ -67,7 +67,7 @@ func (d *arrayDecoder) Decode(ptr unsafe.Pointer, r *Reader) {
 func encoderOfArray(cfg *frozenConfig, schema Schema, typ reflect2.Type) ValEncoder {
 	arr := schema.(*ArraySchema)
 	sliceType := typ.(*reflect2.UnsafeSliceType)
-	encoder := encoderOfType(cfg, arr.Items(), sliceType.Elem())
+	encoder := cfg.EncoderOf(arr.Items(), sliceType.Elem())
 
 	return &arrayEncoder{
 		blockLength: cfg.getBlockLength(),
diff --git a/codec_map.go b/codec_map.go
index 5efdb1d..655cda9 100644
--- a/codec_map.go
+++ b/codec_map.go
@@ -29,7 +29,7 @@ func createEncoderOfMap(cfg *frozenConfig, schema Schema, typ reflect2.Type) Val
 func decoderOfMap(cfg *frozenConfig, schema Schema, typ reflect2.Type) ValDecoder {
 	m := schema.(*MapSchema)
 	mapType := typ.(*reflect2.UnsafeMapType)
-	decoder := decoderOfType(cfg, m.Values(), mapType.Elem())
+	decoder := cfg.DecoderOf(m.Values(), mapType.Elem())
 
 	return &mapDecoder{
 		mapType:  mapType,
@@ -72,7 +72,7 @@ func (d *mapDecoder) Decode(ptr unsafe.Pointer, r *Reader) {
 func encoderOfMap(cfg *frozenConfig, schema Schema, typ reflect2.Type) ValEncoder {
 	m := schema.(*MapSchema)
 	mapType := typ.(*reflect2.UnsafeMapType)
-	encoder := encoderOfType(cfg, m.Values(), mapType.Elem())
+	encoder := cfg.EncoderOf(m.Values(), mapType.Elem())
 
 	return &mapEncoder{
 		blockLength: cfg.getBlockLength(),
diff --git a/codec_union.go b/codec_union.go
index 9cb4031..f9fe056 100644
--- a/codec_union.go
+++ b/codec_union.go
@@ -153,7 +153,7 @@ func decoderOfPtrUnion(cfg *frozenConfig, schema Schema, typ reflect2.Type) ValD
 	_, typeIdx := union.Indices()
 	ptrType := typ.(*reflect2.UnsafePtrType)
 	elemType := ptrType.Elem()
-	decoder := decoderOfType(cfg, union.Types()[typeIdx], elemType)
+	decoder := cfg.DecoderOf(union.Types()[typeIdx], elemType)
 
 	return &unionPtrDecoder{
 		schema:  union,
@@ -195,7 +195,7 @@ func encoderOfPtrUnion(cfg *frozenConfig, schema Schema, typ reflect2.Type) ValE
 	union := schema.(*UnionSchema)
 	nullIdx, typeIdx := union.Indices()
 	ptrType := typ.(*reflect2.UnsafePtrType)
-	encoder := encoderOfType(cfg, union.Types()[typeIdx], ptrType.Elem())
+	encoder := cfg.EncoderOf(union.Types()[typeIdx], ptrType.Elem())
 
 	return &unionPtrEncoder{
 		schema:  union,
@@ -230,7 +230,7 @@ func decoderOfResolvedUnion(cfg *frozenConfig, schema Schema) ValDecoder {
 	for i, schema := range union.Types() {
 		name := unionResolutionName(schema)
 		if typ, err := cfg.resolver.Type(name); err == nil {
-			decoder := decoderOfType(cfg, schema, typ)
+			decoder := cfg.DecoderOf(schema, typ)
 			decoders[i] = decoder
 			types[i] = typ
 			continue


Test patch:
diff --git a/decoder_array_test.go b/decoder_array_test.go
index 8def499..99d51dd 100644
--- a/decoder_array_test.go
+++ b/decoder_array_test.go
@@ -50,6 +50,25 @@ func TestDecoder_ArraySliceOfStruct(t *testing.T) {
 	assert.Equal(t, []TestRecord{{A: 27, B: "foo"}, {A: 27, B: "foo"}}, got)
 }
 
+func TestDecoder_ArrayRecursiveStruct(t *testing.T) {
+	defer ConfigTeardown()
+
+	type record struct {
+		A int      `avro:"a"`
+		B []record `avro:"b"`
+	}
+
+	data := []byte{0x2, 0x3, 0x8, 0x4, 0x0, 0x6, 0x0, 0x0}
+	schema := `{"type": "record", "name": "test", "fields" : [{"name": "a", "type": "int"}, {"name": "b", "type": {"type":"array", "items": "test"}}]}`
+	dec, _ := avro.NewDecoder(schema, bytes.NewReader(data))
+
+	var got record
+	err := dec.Decode(&got)
+
+	assert.NoError(t, err)
+	assert.Equal(t, record{A: 1, B: []record{{A: 2}, {A: 3}}}, got)
+}
+
 func TestDecoder_ArraySliceError(t *testing.T) {
 	defer ConfigTeardown()
 
diff --git a/decoder_map_test.go b/decoder_map_test.go
index db865ca..0c9faea 100644
--- a/decoder_map_test.go
+++ b/decoder_map_test.go
@@ -50,6 +50,25 @@ func TestDecoder_MapMapOfStruct(t *testing.T) {
 	assert.Equal(t, map[string]TestRecord{"foo": {A: 27, B: "foo"}}, got)
 }
 
+func TestDecoder_MapOfRecursiveStruct(t *testing.T) {
+	defer ConfigTeardown()
+
+	type record struct {
+		A int               `avro:"a"`
+		B map[string]record `avro:"b"`
+	}
+
+	data := []byte{0x02, 0x01, 0x0c, 0x06, 0x66, 0x6f, 0x6f, 0x04, 0x0, 0x0}
+	schema := `{"type": "record", "name": "test", "fields" : [{"name": "a", "type": "int"}, {"name": "b", "type": {"type":"map", "values": "test"}}]}`
+	dec, _ := avro.NewDecoder(schema, bytes.NewReader(data))
+
+	var got record
+	err := dec.Decode(&got)
+
+	assert.NoError(t, err)
+	assert.Equal(t, record{A: 1, B: map[string]record{"foo": {A: 2, B: map[string]record{}}}}, got)
+}
+
 func TestDecoder_MapMapError(t *testing.T) {
 	defer ConfigTeardown()
 
diff --git a/decoder_union_test.go b/decoder_union_test.go
index d1421b0..464d12e 100644
--- a/decoder_union_test.go
+++ b/decoder_union_test.go
@@ -8,6 +8,7 @@ import (
 
 	"github.com/hamba/avro"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestDecoder_UnionInvalidType(t *testing.T) {
@@ -236,6 +237,38 @@ func TestDecoder_UnionPtrNotNullable(t *testing.T) {
 	assert.Error(t, err)
 }
 
+func TestDecoder_UnionPtrRecursiveType(t *testing.T) {
+	defer ConfigTeardown()
+
+	type record struct {
+		A int     `avro:"a"`
+		B *record `avro:"b"`
+	}
+
+	data := []byte{0x02, 0x02, 0x04, 0x0}
+	schema := `{
+	"type": "record",
+	"name": "test",
+	"fields" : [
+		{"name": "a", "type": "int"},
+	    {"name": "b", "type": [null, "test"]}
+	]
+}`
+	dec, _ := avro.NewDecoder(schema, bytes.NewReader(data))
+
+	var got record
+	err := dec.Decode(&got)
+
+	require.NoError(t, err)
+	want := record{
+		A: 1,
+		B: &record{
+			A: 2,
+		},
+	}
+	assert.Equal(t, want, got)
+}
+
 func TestDecoder_UnionInterface(t *testing.T) {
 	defer ConfigTeardown()
 
@@ -401,18 +434,54 @@ func TestDecoder_UnionInterfaceRecord(t *testing.T) {
 
 	data := []byte{0x02, 0x36, 0x06, 0x66, 0x6F, 0x6F}
 	schema := `["int", {"type": "record", "name": "test", "fields" : [{"name": "a", "type": "long"}, {"name": "b", "type": "string"}]}]`
-	dec, _ := avro.NewDecoder(schema, bytes.NewReader(data))
+	dec, err := avro.NewDecoder(schema, bytes.NewReader(data))
+	require.NoError(t, err)
 
 	var got interface{}
-	err := dec.Decode(&got)
+	err = dec.Decode(&got)
 
-	assert.NoError(t, err)
-	assert.IsType(t, &TestRecord{}, got)
+	require.NoError(t, err)
+	require.IsType(t, &TestRecord{}, got)
 	rec := got.(*TestRecord)
 	assert.Equal(t, int64(27), rec.A)
 	assert.Equal(t, "foo", rec.B)
 }
 
+func TestDecoder_UnionInterfaceRecursiveType(t *testing.T) {
+	defer ConfigTeardown()
+
+	type record struct {
+		A int         `avro:"a"`
+		B interface{} `avro:"b"`
+	}
+
+	data := []byte{0x02, 0x02, 0x04, 0x0}
+	schema := `{
+	"type": "record",
+	"name": "test",
+	"fields" : [
+		{"name": "a", "type": "int"},
+	    {"name": "b", "type": [null, "test"]}
+	]
+}`
+	avro.Register("test", record{})
+
+	dec, _ := avro.NewDecoder(schema, bytes.NewReader(data))
+
+	var got record
+	err := dec.Decode(&got)
+
+	require.NoError(t, err)
+	require.IsType(t, record{}, got)
+	want := record{
+		A: 1,
+		B: record{
+			A: 2,
+		},
+	}
+	assert.Equal(t, want, got)
+}
+
 func TestDecoder_UnionInterfaceRecordNotReused(t *testing.T) {
 	defer ConfigTeardown()
 
diff --git a/encoder_array_test.go b/encoder_array_test.go
index c99b269..64f0576 100644
--- a/encoder_array_test.go
+++ b/encoder_array_test.go
@@ -63,6 +63,26 @@ func TestEncoder_ArrayOfStruct(t *testing.T) {
 	assert.Equal(t, []byte{0x03, 0x14, 0x36, 0x06, 0x66, 0x6f, 0x6f, 0x36, 0x06, 0x66, 0x6f, 0x6f, 0x0}, buf.Bytes())
 }
 
+func TestEncoder_ArrayRecursiveStruct(t *testing.T) {
+	defer ConfigTeardown()
+
+	type record struct {
+		A int      `avro:"a"`
+		B []record `avro:"b"`
+	}
+
+	schema := `{"type": "record", "name": "test", "fields" : [{"name": "a", "type": "int"}, {"name": "b", "type": {"type":"array", "items": "test"}}]}`
+	buf := bytes.NewBuffer([]byte{})
+	enc, err := avro.NewEncoder(schema, buf)
+	assert.NoError(t, err)
+
+	rec := record{A: 1, B: []record{{A: 2}, {A: 3}}}
+	err = enc.Encode(rec)
+
+	assert.NoError(t, err)
+	assert.Equal(t, []byte{0x2, 0x3, 0x8, 0x4, 0x0, 0x6, 0x0, 0x0}, buf.Bytes())
+}
+
 func TestEncoder_ArrayError(t *testing.T) {
 	defer ConfigTeardown()
 
diff --git a/encoder_map_test.go b/encoder_map_test.go
index 1d411a1..8e5de23 100644
--- a/encoder_map_test.go
+++ b/encoder_map_test.go
@@ -63,6 +63,26 @@ func TestEncoder_MapOfStruct(t *testing.T) {
 	assert.Equal(t, []byte{0x01, 0x12, 0x06, 0x66, 0x6F, 0x6F, 0x36, 0x06, 0x66, 0x6f, 0x6f, 0x0}, buf.Bytes())
 }
 
+func TestEncoder_MapOfRecursiveStruct(t *testing.T) {
+	defer ConfigTeardown()
+
+	type record struct {
+		A int               `avro:"a"`
+		B map[string]record `avro:"b"`
+	}
+
+	schema := `{"type": "record", "name": "test", "fields" : [{"name": "a", "type": "int"}, {"name": "b", "type": {"type":"map", "values": "test"}}]}`
+	buf := bytes.NewBuffer([]byte{})
+	enc, err := avro.NewEncoder(schema, buf)
+	assert.NoError(t, err)
+
+	rec := record{A: 1, B: map[string]record{"foo": {A: 2}}}
+	err = enc.Encode(rec)
+
+	assert.NoError(t, err)
+	assert.Equal(t, []byte{0x02, 0x01, 0x0c, 0x06, 0x66, 0x6f, 0x6f, 0x04, 0x0, 0x0}, buf.Bytes())
+}
+
 func TestEncoder_MapInvalidKeyType(t *testing.T) {
 	defer ConfigTeardown()
 
diff --git a/encoder_union_test.go b/encoder_union_test.go
index 8b89f39..943a4d6 100644
--- a/encoder_union_test.go
+++ b/encoder_union_test.go
@@ -238,6 +238,38 @@ func TestEncoder_UnionPtrNotNullable(t *testing.T) {
 	assert.Error(t, err)
 }
 
+func TestEncoder_UnionPtrRecursiveType(t *testing.T) {
+	defer ConfigTeardown()
+
+	type record struct {
+		A int     `avro:"a"`
+		B *record `avro:"b"`
+	}
+
+	schema := `{
+	"type": "record",
+	"name": "test",
+	"fields" : [
+		{"name": "a", "type": "int"},
+	    {"name": "b", "type": [null, "test"]}
+	]
+}`
+	buf := bytes.NewBuffer([]byte{})
+	enc, err := avro.NewEncoder(schema, buf)
+	assert.NoError(t, err)
+
+	rec := record{
+		A: 1,
+		B: &record{
+			A: 2,
+		},
+	}
+	err = enc.Encode(rec)
+
+	assert.NoError(t, err)
+	assert.Equal(t, []byte{0x02, 0x02, 0x04, 0x0}, buf.Bytes())
+}
+
 func TestEncoder_UnionInterface(t *testing.T) {
 	defer ConfigTeardown()
 
@@ -366,6 +398,38 @@ func TestEncoder_UnionInterfaceNamed(t *testing.T) {
 	assert.Equal(t, []byte{0x02, 0x02}, buf.Bytes())
 }
 
+func TestEncoder_UnionInterfaceRecursiveType(t *testing.T) {
+	defer ConfigTeardown()
+
+	type record struct {
+		A int         `avro:"a"`
+		B interface{} `avro:"b"`
+	}
+
+	schema := `{
+	"type": "record",
+	"name": "test",
+	"fields" : [
+		{"name": "a", "type": "int"},
+	    {"name": "b", "type": [null, "test"]}
+	]
+}`
+	buf := bytes.NewBuffer([]byte{})
+	enc, err := avro.NewEncoder(schema, buf)
+	assert.NoError(t, err)
+
+	rec := record{
+		A: 1,
+		B: &record{
+			A: 2,
+		},
+	}
+	err = enc.Encode(rec)
+
+	assert.NoError(t, err)
+	assert.Equal(t, []byte{0x02, 0x02, 0x04, 0x0}, buf.Bytes())
+}
+
 func TestEncoder_UnionInterfaceWithTime(t *testing.T) {
 	defer ConfigTeardown()