api: make trees.packed not null (#60)

Booleans with 3 possible values are needlessly confusing.

Unpacked data is padded to 32 bytes. Most of the time, callers will
provide a list of [20]byte values (ETH addresses) --which is packed.

api/migrations/migrations.go

@@ -70,8 +70,19 @@ var Migrations = []migrate.Migration{
 	{
 		Name: "2022-08-22.1.add-inserted-at.sql",
 		SQL: `
-		ALTER TABLE trees 
+		ALTER TABLE trees
 		ADD COLUMN "inserted_at" timestamptz NOT NULL DEFAULT now();
 		`,
 	},
+	{
+		Name: "2022-08-30.0.packed-bool.sql",
+		SQL: `
+		UPDATE trees SET packed = true
+		WHERE packed IS NULL;
+
+		ALTER TABLE trees
+		ALTER COLUMN packed
+		SET NOT NULL;
+		`,
+	},
 }

api/tree.go

@@ -1,7 +1,6 @@
 package api
 
 import (
-	"database/sql"
 	"encoding/json"
 	"errors"
 	"net/http"
@@ -74,32 +73,6 @@ func addrPacked(leaf []byte, ltd []string) common.Address {
 	return common.Address{}
 }
 
-type jsonNullBool struct {
-	sql.NullBool
-}
-
-func (jnb *jsonNullBool) UnmarshalJSON(d []byte) error {
-	var b *bool
-	if err := json.Unmarshal(d, &b); err != nil {
-		return err
-	}
-	if b == nil {
-		jnb.Valid = false
-		return nil
-	}
-
-	jnb.Valid = true
-	jnb.Bool = *b
-	return nil
-}
-
-func (jnb jsonNullBool) MarshalJSON() ([]byte, error) {
-	if jnb.Valid {
-		return json.Marshal(jnb.Bool)
-	}
-	return json.Marshal(nil)
-}
-
 func encodeProof(p [][]byte) []string {
 	var res []string
 	for i := range p {
@@ -111,7 +84,7 @@ func encodeProof(p [][]byte) []string {
 type createTreeReq struct {
 	Leaves []hexutil.Bytes `json:"unhashedLeaves"`
 	Ltd    []string        `json:"leafTypeDescriptor"`
-	Packed jsonNullBool    `json:"packedEncoding"`
+	Packed bool            `json:"packedEncoding"`
 }
 
 type createTreeResp struct {
@@ -158,7 +131,7 @@ func (s *Server) CreateTree(w http.ResponseWriter, r *http.Request) {
 		}
 		proofs = append(proofs, proofItem{
 			Leaf:  hexutil.Encode(l),
-			Addr:  leaf2Addr(l, req.Ltd, req.Packed.Bool).Hex(),
+			Addr:  leaf2Addr(l, req.Ltd, req.Packed).Hex(),
 			Proof: encodeProof(pf),
 		})
 	}
@@ -177,7 +150,7 @@ func (s *Server) CreateTree(w http.ResponseWriter, r *http.Request) {
 		tree.Root(),
 		req.Leaves,
 		req.Ltd,
-		req.Packed.NullBool,
+		req.Packed,
 		proofs,
 	)
 	if err != nil {
@@ -192,7 +165,7 @@ type getTreeResp struct {
 	UnhashedLeaves []hexutil.Bytes `json:"unhashedLeaves"`
 	LeafCount      int             `json:"leafCount"`
 	Ltd            []string        `json:"leafTypeDescriptor"`
-	Packed         jsonNullBool    `json:"packedEncoding"`
+	Packed         bool            `json:"packedEncoding"`
 }
 
 func (s *Server) GetTree(w http.ResponseWriter, r *http.Request) {