Merge pull request #36967 from hashicorp/b-SimpleSchemaSetFunc-crash

Fix `panic: interface conversion: interface {} is nil, not map[string]interface {}` in `sdkv2.SimpleSchemaSetFunc`

.changelog/36967.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+resource/aws_db_proxy: Fix `interface conversion: interface {} is nil, not map[string]interface {}` panic when `auth` is empty (`{}`)
+```

internal/sdkv2/set.go

@@ -22,19 +22,20 @@ func SimpleSchemaSetFunc(keys ...string) schema.SchemaSetFunc {
 	return func(v interface{}) int {
 		var str strings.Builder
 
-		m := v.(map[string]interface{})
-		for _, key := range keys {
-			if v, ok := m[key]; ok {
-				switch v := v.(type) {
-				case bool:
-					str.WriteRune('-')
-					str.WriteString(strconv.FormatBool(v))
-				case int:
-					str.WriteRune('-')
-					str.WriteString(strconv.Itoa(v))
-				case string:
-					str.WriteRune('-')
-					str.WriteString(v)
+		if m, ok := v.(map[string]interface{}); ok {
+			for _, key := range keys {
+				if v, ok := m[key]; ok {
+					switch v := v.(type) {
+					case bool:
+						str.WriteRune('-')
+						str.WriteString(strconv.FormatBool(v))
+					case int:
+						str.WriteRune('-')
+						str.WriteString(strconv.Itoa(v))
+					case string:
+						str.WriteRune('-')
+						str.WriteString(v)
+					}
 				}
 			}
 		}

internal/sdkv2/set_test.go

@@ -23,6 +23,17 @@ func TestStringCaseInsensitiveSetFunc(t *testing.T) {
 	}
 }
 
+func TestSimpleSchemaSetFuncNil(t *testing.T) {
+	t.Parallel()
+
+	var v interface{}
+	f := SimpleSchemaSetFunc("key1", "key3", "key4")
+
+	if got, want := f(v), 0; got != want {
+		t.Errorf("SimpleSchemaSetFunc(%q) err %q, want %q", v, got, want)
+	}
+}
+
 func TestSimpleSchemaSetFunc(t *testing.T) {
 	t.Parallel()