s3api: preserve lifecycle config responses for Terraform (#8805)

* s3api: preserve lifecycle configs for terraform

* s3api: bound lifecycle config request bodies

* s3api: make bucket config updates copy-on-write

* s3api: tighten string slice cloning

weed/s3api/policy_engine/types.go

@@ -100,6 +100,11 @@ func NewStringOrStringSlicePtr(values ...string) *StringOrStringSlice {
 	return &StringOrStringSlice{values: values}
 }
 
+// CloneStringOrStringSlice returns a copy with its own backing slice.
+func CloneStringOrStringSlice(value StringOrStringSlice) StringOrStringSlice {
+	return StringOrStringSlice{values: append([]string(nil), value.values...)}
+}
+
 // PolicyConditions represents policy conditions with proper typing
 type PolicyConditions map[string]map[string]StringOrStringSlice
 

weed/s3api/policy_engine/types_test.go

@@ -0,0 +1,17 @@
+package policy_engine
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCloneStringOrStringSliceCopiesBackingSlice(t *testing.T) {
+	original := NewStringOrStringSlice("s3:GetObject", "s3:PutObject")
+
+	cloned := CloneStringOrStringSlice(original)
+	cloned.values[0] = "s3:DeleteObject"
+
+	assert.Equal(t, []string{"s3:GetObject", "s3:PutObject"}, original.Strings())
+	assert.Equal(t, []string{"s3:DeleteObject", "s3:PutObject"}, cloned.Strings())
+}