feat: enhance StatefulSet immutable field error message to show specific field changes

Signed-off-by: Atif Ali <[email protected]>

Author: aali309

pkg/sync/sync_context.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"reflect"
 	"sort"
 	"strings"
 	"sync"
@@ -1005,6 +1006,40 @@ func (sc *syncContext) applyObject(t *syncTask, dryRun, validate bool) (common.R
 		message, err = sc.resourceOps.ApplyResource(context.TODO(), t.targetObj, dryRunStrategy, force, validate, serverSideApply, sc.serverSideApplyManager, false)
 	}
 	if err != nil {
+		// Check if this is a StatefulSet immutable field error
+		if strings.Contains(err.Error(), "updates to statefulset spec for fields other than") {
+			current := t.liveObj
+			desired := t.targetObj
+
+			if current != nil && desired != nil {
+				currentSpec, _, _ := unstructured.NestedMap(current.Object, "spec")
+				desiredSpec, _, _ := unstructured.NestedMap(desired.Object, "spec")
+
+				mutableFields := map[string]bool{
+					"replicas":                             true,
+					"ordinals":                             true,
+					"template":                             true,
+					"updateStrategy":                       true,
+					"persistentVolumeClaimRetentionPolicy": true,
+					"minReadySeconds":                      true,
+				}
+
+				var changes []string
+				for k, desiredVal := range desiredSpec {
+					if !mutableFields[k] {
+						currentVal, exists := currentSpec[k]
+						if !exists || !reflect.DeepEqual(currentVal, desiredVal) {
+							changes = append(changes, fmt.Sprintf("  %s -> from %v to %v", k, currentVal, desiredVal))
+						}
+					}
+				}
+
+				if len(changes) > 0 {
+					return common.ResultCodeSyncFailed, fmt.Sprintf("one or more objects failed to apply, reason: attempting to change immutable fields:\n%s\nForbidden: updates to statefulset spec for fields other than 'replicas', 'ordinals', 'template', 'updateStrategy', 'persistentVolumeClaimRetentionPolicy' and 'minReadySeconds' are forbidden",
+						strings.Join(changes, "\n"))
+				}
+			}
+		}
 		return common.ResultCodeSyncFailed, err.Error()
 	}
 	if kube.IsCRD(t.targetObj) && !dryRun {