feat(simulation): Implement store decoder implementation from collections schema (#16074)

Co-authored-by: unknown unknown <unknown@unknown>

types/simulation/collections.go

@@ -0,0 +1,52 @@
+package simulation
+
+import (
+	"bytes"
+	"fmt"
+
+	"cosmossdk.io/collections"
+	collcodec "cosmossdk.io/collections/codec"
+
+	"github.com/cosmos/cosmos-sdk/types/kv"
+)
+
+func NewStoreDecoderFuncFromCollectionsSchema(schema collections.Schema) func(kvA, kvB kv.Pair) string {
+	colls := schema.ListCollections()
+	prefixes := make([][]byte, len(colls))
+	valueCodecs := make([]collcodec.UntypedValueCodec, len(colls))
+	for i, coll := range colls {
+		prefixes[i] = coll.GetPrefix()
+		valueCodecs[i] = coll.ValueCodec()
+	}
+
+	return func(kvA, kvB kv.Pair) string {
+		for i, prefix := range prefixes {
+			if bytes.HasPrefix(kvA.Key, prefix) {
+				if !bytes.HasPrefix(kvB.Key, prefix) {
+					panic(fmt.Sprintf("prefix mismatch, keyA has prefix %x (%s), but keyB does not %x (%s)", prefix, prefix, kvB.Key, kvB.Key))
+				}
+				vc := valueCodecs[i]
+				// unmarshal kvA.Value to the corresponding type
+				vA, err := vc.Decode(kvA.Value)
+				if err != nil {
+					panic(err)
+				}
+				// unmarshal kvB.Value to the corresponding type
+				vB, err := vc.Decode(kvB.Value)
+				if err != nil {
+					panic(err)
+				}
+				vAString, err := vc.Stringify(vA)
+				if err != nil {
+					panic(err)
+				}
+				vBString, err := vc.Stringify(vB)
+				if err != nil {
+					panic(err)
+				}
+				return vAString + "\n" + vBString
+			}
+		}
+		panic(fmt.Errorf("unexpected key %X (%s)", kvA.Key, kvA.Key))
+	}
+}

types/simulation/collections_test.go

@@ -0,0 +1,71 @@
+package simulation
+
+import (
+	"testing"
+
+	"cosmossdk.io/collections"
+	"cosmossdk.io/collections/colltest"
+	"github.com/cosmos/cosmos-sdk/types/kv"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewStoreDecoderFuncFromCollectionsSchema(t *testing.T) {
+	store, _ := colltest.MockStore()
+	sb := collections.NewSchemaBuilder(store)
+
+	prefixM1 := collections.NewPrefix("map_1")
+	prefixM2 := collections.NewPrefix("map_2")
+
+	m1 := collections.NewMap(sb, prefixM1, "map_1", collections.StringKey, collections.StringValue)
+	m2 := collections.NewMap(sb, prefixM2, "map_2", collections.Int32Key, collections.Int32Value)
+
+	schema, err := sb.Build()
+	require.NoError(t, err)
+
+	// create a new store decoder function from the schema
+	dec := NewStoreDecoderFuncFromCollectionsSchema(schema)
+
+	key1M1, err := collections.EncodeKeyWithPrefix(prefixM1, m1.KeyCodec(), "key_1")
+	require.NoError(t, err)
+	key2M1, err := collections.EncodeKeyWithPrefix(prefixM1, m1.KeyCodec(), "key_2")
+	require.NoError(t, err)
+	key1M2, err := collections.EncodeKeyWithPrefix(prefixM2, m2.KeyCodec(), int32(1))
+	require.NoError(t, err)
+	key2M2, err := collections.EncodeKeyWithPrefix(prefixM2, m2.KeyCodec(), int32(2))
+	require.NoError(t, err)
+
+	storeDec1 := dec(kv.Pair{
+		Key:   key1M1,
+		Value: []byte("value_1"),
+	}, kv.Pair{
+		Key:   key2M1,
+		Value: []byte("value_2"),
+	})
+	require.Equal(t, "value_1\nvalue_2", storeDec1)
+
+	storeDec2 := dec(kv.Pair{
+		Key:   key1M2,
+		Value: []byte{0, 0, 0, 1},
+	}, kv.Pair{
+		Key:   key2M2,
+		Value: []byte{0, 0, 0, 2},
+	})
+
+	require.Equal(t, "-2147483647\n-2147483646", storeDec2)
+
+	// test key conflict
+
+	require.Panics(t, func() {
+		dec(
+			kv.Pair{Key: append(prefixM1.Bytes(), 0x1)},
+			kv.Pair{Key: append(prefixM2.Bytes(), 0x1)},
+		)
+	}, "must panic when keys do not have the same prefix")
+
+	require.Panics(t, func() {
+		dec(
+			kv.Pair{Key: []byte("unknown_1")},
+			kv.Pair{Key: []byte("unknown_2")},
+		)
+	}, "must panic on unknown prefixes")
+}

types/simulation/rand_util.go

@@ -172,6 +172,6 @@ func (ms multiSource) Int63() (r int64) {
 	return r
 }
 
-func (ms multiSource) Seed(seed int64) {
+func (ms multiSource) Seed(_ int64) {
 	panic("multiSource Seed should not be called")
 }