fix(x/auth/tx): avoid panic from intoAnyV2 when v1.PublicKey is optional (backport #23148) (#23187)

Co-authored-by: mmsqe <mavis@crypto.com>
Co-authored-by: Julien Robert <julien@rbrt.fr>

CHANGELOG.md

@@ -40,6 +40,10 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 Every module contains its own CHANGELOG.md. Please refer to the module you are interested in.
 
+### Bug Fixes
+
+* (x/auth/tx) [#23148](https://github.com/cosmos/cosmos-sdk/pull/23148) Avoid panic from intoAnyV2 when v1.PublicKey is optional.
+
 ### Deprecated
 
 * (modules) [#22994](https://github.com/cosmos/cosmos-sdk/pull/22994) Deprecate `Invariants` and associated methods.

x/auth/tx/builder.go

@@ -293,9 +293,11 @@ func intoV2SignerInfo(v1s []*tx.SignerInfo) []*txv1beta1.SignerInfo {
 		modeInfoV2 := new(txv1beta1.ModeInfo)
 		intoV2ModeInfo(v1.ModeInfo, modeInfoV2)
 		v2 := &txv1beta1.SignerInfo{
-			PublicKey: intoAnyV2([]*codectypes.Any{v1.PublicKey})[0],
-			ModeInfo:  modeInfoV2,
-			Sequence:  v1.Sequence,
+			ModeInfo: modeInfoV2,
+			Sequence: v1.Sequence,
+		}
+		if v1.PublicKey != nil {
+			v2.PublicKey = intoAnyV2([]*codectypes.Any{v1.PublicKey})[0]
 		}
 		v2s[i] = v2
 	}

x/auth/tx/builder_test.go

@@ -0,0 +1,15 @@
+package tx
+
+import (
+	"testing"
+
+	any "github.com/cosmos/gogoproto/types/any"
+	"github.com/stretchr/testify/require"
+
+	"github.com/cosmos/cosmos-sdk/types/tx"
+)
+
+func TestIntoV2SignerInfo(t *testing.T) {
+	require.NotNil(t, intoV2SignerInfo([]*tx.SignerInfo{{}}))
+	require.NotNil(t, intoV2SignerInfo([]*tx.SignerInfo{{PublicKey: &any.Any{}}}))
+}