fix: unmarshalling issue with multisig keys in master (backport cosmo…

…s#10061) (cosmos#10169)

* fix: unmarshalling issue with multisig keys in master (cosmos#10061)

(cherry picked from commit 3d3bc7c)

# Conflicts:
#	CHANGELOG.md

* fix conflicts

Co-authored-by: Henrik Aasted Sørensen <has@bitcraft.dk>
Co-authored-by: Robert Zaremba <robert@zaremba.ch>

CHANGELOG.md

@@ -43,6 +43,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ### Bug Fixes
 
 * (x/genutil) [#10104](https://github.com/cosmos/cosmos-sdk/pull/10104) Ensure the `init` command reads the `--home` flag value correctly.
+* [\#10061](https://github.com/cosmos/cosmos-sdk/pull/10061) Ensure that `LegacyAminoPubKey` struct correctly unmarshals from JSON
 
 ## [v0.44.0](https://github.com/cosmos/cosmos-sdk/releases/tag/v0.44.0) - 2021-09-01
 

crypto/keys/multisig/amino.go

@@ -78,7 +78,9 @@ func (m *LegacyAminoPubKey) UnmarshalAminoJSON(tmPk tmMultisig) error {
 	// Instead of just doing `*m = *protoPk`, we prefer to modify in-place the
 	// existing Anys inside `m` (instead of allocating new Anys), as so not to
 	// break the `.compat` fields in the existing Anys.
+	m.PubKeys = make([]*types.Any, len(protoPk.PubKeys))
 	for i := range m.PubKeys {
+		m.PubKeys[i] = &types.Any{}
 		m.PubKeys[i].TypeUrl = protoPk.PubKeys[i].TypeUrl
 		m.PubKeys[i].Value = protoPk.PubKeys[i].Value
 	}

crypto/keys/multisig/multisig_test.go

@@ -428,6 +428,14 @@ func TestAminoUnmarshalJSON(t *testing.T) {
 	require.NoError(t, err)
 	lpk := pk.(*kmultisig.LegacyAminoPubKey)
 	require.Equal(t, uint32(3), lpk.Threshold)
+	require.Equal(t, 5, len(pk.(*kmultisig.LegacyAminoPubKey).PubKeys))
+
+	for _, key := range pk.(*kmultisig.LegacyAminoPubKey).PubKeys {
+		require.NotNil(t, key)
+		pk := secp256k1.PubKey{}
+		err := pk.Unmarshal(key.Value)
+		require.NoError(t, err)
+	}
 }
 
 func TestProtoMarshalJSON(t *testing.T) {