Add ConditionsFromStatus and SetApplyConfigurationStatusCondition helpers

Introduces SSA-friendly helpers to convert []metav1.Condition into a slice of ConditionApplyConfiguration and to set a condition by type while mirroring meta.SetStatusCondition's LastTransitionTime semantics. Foundation commit for migrating controllers to server-side apply; no controller currently uses them.

Extracted from 0b757a84915f4ccdfa11c6dbd63eb10a3bfba582.

Author: fwiesel

internal/utils/conditions.go

@@ -0,0 +1,116 @@
+/*
+SPDX-FileCopyrightText: Copyright 2024 SAP SE or an SAP affiliate company and cobaltcore-dev contributors
+SPDX-License-Identifier: Apache-2.0
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package utils
+
+import (
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	k8sacmetav1 "k8s.io/client-go/applyconfigurations/meta/v1"
+)
+
+// ConditionsFromStatus converts a []metav1.Condition (as stored in a status
+// subresource) into a []k8sacmetav1.ConditionApplyConfiguration suitable for
+// use with server-side apply. All fields including LastTransitionTime are
+// preserved verbatim.
+func ConditionsFromStatus(conditions []metav1.Condition) []k8sacmetav1.ConditionApplyConfiguration {
+	result := make([]k8sacmetav1.ConditionApplyConfiguration, len(conditions))
+	for i := range conditions {
+		c := &conditions[i]
+		result[i] = k8sacmetav1.ConditionApplyConfiguration{
+			Type:               &c.Type,
+			Status:             &c.Status,
+			Reason:             &c.Reason,
+			Message:            &c.Message,
+			LastTransitionTime: &c.LastTransitionTime,
+		}
+	}
+	return result
+}
+
+// SetApplyConfigurationStatusCondition sets the corresponding condition in
+// conditions to newCondition and returns true if the conditions are changed by
+// this call. It mirrors the behaviour of k8s.io/apimachinery/pkg/api/meta.SetStatusCondition:
+//
+//  1. If a condition of the specified type does not exist, newCondition is
+//     appended. LastTransitionTime is set to now if not provided.
+//  2. If a condition of the specified type already exists, all fields are
+//     updated. LastTransitionTime is updated to now (or the provided value)
+//     only when Status changes; otherwise the existing LastTransitionTime is
+//     preserved.
+func SetApplyConfigurationStatusCondition(conditions *[]k8sacmetav1.ConditionApplyConfiguration, newCondition k8sacmetav1.ConditionApplyConfiguration) (changed bool) {
+	if conditions == nil {
+		return false
+	}
+
+	// Find existing entry by type
+	var existing *k8sacmetav1.ConditionApplyConfiguration
+	for i := range *conditions {
+		if (*conditions)[i].Type != nil && *(*conditions)[i].Type == *newCondition.Type {
+			existing = &(*conditions)[i]
+			break
+		}
+	}
+
+	if existing == nil {
+		// New condition: set LastTransitionTime if not provided
+		if newCondition.LastTransitionTime == nil {
+			now := metav1.Now()
+			newCondition.LastTransitionTime = &now
+		}
+		*conditions = append(*conditions, newCondition)
+		return true
+	}
+
+	// Existing condition: update fields, handle LastTransitionTime
+	statusChanged := existing.Status == nil || newCondition.Status == nil ||
+		*existing.Status != *newCondition.Status
+
+	if statusChanged {
+		existing.Status = newCondition.Status
+		if newCondition.LastTransitionTime != nil {
+			existing.LastTransitionTime = newCondition.LastTransitionTime
+		} else {
+			now := metav1.Now()
+			existing.LastTransitionTime = &now
+		}
+		changed = true
+	}
+	// When status is unchanged, LastTransitionTime is intentionally preserved.
+
+	if strChanged(&existing.Reason, newCondition.Reason) {
+		existing.Reason = newCondition.Reason
+		changed = true
+	}
+	if strChanged(&existing.Message, newCondition.Message) {
+		existing.Message = newCondition.Message
+		changed = true
+	}
+
+	return changed
+}
+
+// strChanged reports whether the pointer value of b differs from the current
+// value at a.
+func strChanged(a **string, b *string) bool {
+	if *a == nil && b == nil {
+		return false
+	}
+	if *a == nil || b == nil {
+		return true
+	}
+	return **a != *b
+}