From cedfd51f1f2669ac178695eef9ac90e7da1d6ac5 Mon Sep 17 00:00:00 2001
From: jmank88 <jmank88@gmail.com>
Date: Sat, 4 Feb 2023 12:43:30 -0600
Subject: [PATCH] add TestUnmarshalArrayOfTables and placeholder error; towards
 #839

---
 unmarshaler.go      |  6 +++++-
 unmarshaler_test.go | 14 +++++++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/unmarshaler.go b/unmarshaler.go
index 70f6ec57..35f6c4d6 100644
--- a/unmarshaler.go
+++ b/unmarshaler.go
@@ -377,7 +377,11 @@ func (d *decoder) handleArrayTableCollection(key unstable.Iterator, v reflect.Va
 
 		return v, nil
 	case reflect.Slice:
-		elem := v.Index(v.Len() - 1)
+		idx := v.Len() - 1
+		if idx < 0 {
+			return v, fmt.Errorf("TODO uninitialized array table")
+		}
+		elem := v.Index(idx)
 		x, err := d.handleArrayTable(key, elem)
 		if err != nil || d.skipUntilTable {
 			return reflect.Value{}, err
diff --git a/unmarshaler_test.go b/unmarshaler_test.go
index 88255d14..f49d2b14 100644
--- a/unmarshaler_test.go
+++ b/unmarshaler_test.go
@@ -11,9 +11,10 @@ import (
 	"testing"
 	"time"
 
-	"github.com/pelletier/go-toml/v2"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+
+	"github.com/pelletier/go-toml/v2"
 )
 
 func ExampleDecoder_DisallowUnknownFields() {
@@ -3301,3 +3302,14 @@ func TestUnmarshalEmbedNonString(t *testing.T) {
 	require.NoError(t, err)
 	require.Nil(t, d.Foo)
 }
+
+func TestUnmarshalArrayOfTables(t *testing.T) {
+	m := struct {
+		A []struct {
+			B struct{}
+		}
+	}{}
+	require.NotPanics(t, func() {
+		require.Error(t, toml.Unmarshal([]byte(`[[A.B]]`), &m))
+	})
+}