feat(bindnode): infer links and Any from Go types

node/bindnode/infer.go

@@ -380,7 +380,6 @@ func inferSchema(typ reflect.Type, level int) schema.Type {
 	if level > maxRecursionLevel {
 		panic(fmt.Sprintf("inferSchema: refusing to recurse past %d levels", maxRecursionLevel))
 	}
-	// TODO: support Link and Any
 	switch typ.Kind() {
 	case reflect.Bool:
 		return schemaTypeBool
@@ -391,6 +390,12 @@ func inferSchema(typ reflect.Type, level int) schema.Type {
 	case reflect.String:
 		return schemaTypeString
 	case reflect.Struct:
+		// these types must match exactly since we need symmetry of being able to
+		// get the values an also assign values to them
+		if typ == goTypeCid || typ == goTypeCidLink {
+			return schemaTypeLink
+		}
+
 		fieldsSchema := make([]schema.StructField, typ.NumField())
 		for i := range fieldsSchema {
 			field := typ.Field(i)
@@ -430,8 +435,18 @@ func inferSchema(typ reflect.Type, level int) schema.Type {
 		typSchema := schema.SpawnList(name, etypSchema.Name(), nullable)
 		defaultTypeSystem.Accumulate(typSchema)
 		return typSchema
+	case reflect.Interface:
+		// these types must match exactly since we need symmetry of being able to
+		// get the values an also assign values to them
+		if typ == goTypeLink {
+			return schemaTypeLink
+		}
+		if typ == goTypeNode {
+			return schemaTypeAny
+		}
+		panic("bindnode: unable to infer from interface")
 	}
-	panic(typ.Kind().String())
+	panic(fmt.Sprintf("bindnode: unable to infer from type %s", typ.Kind().String()))
 }
 
 // There are currently 27 reflect.Kind iota values,

node/bindnode/infer_test.go

@@ -14,6 +14,7 @@ import (
 	"testing"
 
 	qt "github.com/frankban/quicktest"
+	"github.com/google/go-cmp/cmp"
 	"github.com/ipfs/go-cid"
 
 	"github.com/ipld/go-ipld-prime"
@@ -1211,3 +1212,40 @@ func TestEmptyTypedAssignNode(t *testing.T) {
 		})
 	}
 }
+
+func TestInferLinksAndAny(t *testing.T) {
+	link, err := cid.Decode("bafybeigdyrzt5sfp7udm7hu76uh7y26nf3efuylqabf3oclgtqy55fbzdi")
+	qt.Assert(t, err, qt.IsNil)
+
+	type Nd struct {
+		A cid.Cid
+		B cidlink.Link
+		C datamodel.Link
+		D datamodel.Node
+	}
+
+	proto := bindnode.Prototype(&Nd{}, nil)
+
+	expected := &Nd{
+		A: link,
+		B: cidlink.Link{Cid: link},
+		C: cidlink.Link{Cid: link},
+		D: basicnode.NewString("Any Here"),
+	}
+
+	node := bindnode.Wrap(expected, proto.Type())
+
+	byts, err := ipld.Encode(node, dagjson.Encode)
+	qt.Assert(t, err, qt.IsNil)
+
+	qt.Assert(t, string(byts), qt.Equals, `{"A":{"/":"bafybeigdyrzt5sfp7udm7hu76uh7y26nf3efuylqabf3oclgtqy55fbzdi"},"B":{"/":"bafybeigdyrzt5sfp7udm7hu76uh7y26nf3efuylqabf3oclgtqy55fbzdi"},"C":{"/":"bafybeigdyrzt5sfp7udm7hu76uh7y26nf3efuylqabf3oclgtqy55fbzdi"},"D":"Any Here"}`)
+
+	nodeRt, err := ipld.DecodeUsingPrototype(byts, dagjson.Decode, proto)
+	qt.Assert(t, err, qt.IsNil)
+
+	if actual, ok := bindnode.Unwrap(nodeRt).(*Nd); ok {
+		qt.Assert(t, actual, qt.CmpEquals(cmp.Comparer(func(x, y cid.Cid) bool { return x.Equals(y) })), expected)
+	} else {
+		t.Error("expected *Nd from Unwrap")
+	}
+}