feat(trait): add InfluencesBuild() func

docs/modules/ROOT/pages/architecture/traits.adoc

@@ -43,6 +43,7 @@ type Trait interface {
 	Configure(environment *Environment) (bool, error)
 	Apply(environment *Environment) error
 	InfluencesKit() bool
+	InfluencesBuild(this, prev map[string]interface{}) bool
 	IsPlatformTrait() bool
 	RequiresIntegrationPlatform() bool
 	IsAllowedInProfile(v1.TraitProfile) bool
@@ -58,4 +59,6 @@ The `Order()` method helps in resolving the order of execution of different trai
 
 The `InfluencesKit()`, `IsPlatformTrait()` and `RequiresIntegrationPlatform()` methods are easy to understand. They are used to determine if a trait has to influence an `IntegrationKit` build/initialization, if it's a platform trait (ie, needed by the platform itself) or are requiring the presence of an `IntegrationPlatform`.
 
+The presence of `InfluencesBuild()` will let specify the level of granularity of a trait down to its properties for a rebuild. So, if you need, you can compare the traits properties coming from the `prev` (previous) Integration to decide if it is worth to rebuild an Integration or the trait can reuse the one already provided in `this` version.
+
 Finally, through the `IsAllowedInProfile()` method we can override the default behavior (allow the trait for any profile). We must specify the profile we expect for this trait to be executed properly.

e2e/common/traits/camel_test.go

@@ -0,0 +1,61 @@
+//go:build integration
+// +build integration
+
+// To enable compilation of this file in Goland, go to "Settings -> Go -> Vendoring & Build Tags -> Custom Tags" and add "integration"
+
+/*
+Licensed to the Apache Software Foundation (ASF) under one or more
+contributor license agreements.  See the NOTICE file distributed with
+this work for additional information regarding copyright ownership.
+The ASF licenses this file to You 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 traits
+
+import (
+	"testing"
+
+	. "github.com/onsi/gomega"
+
+	corev1 "k8s.io/api/core/v1"
+
+	. "github.com/apache/camel-k/v2/e2e/support"
+	v1 "github.com/apache/camel-k/v2/pkg/apis/camel/v1"
+)
+
+func TestCamelTrait(t *testing.T) {
+	RegisterTestingT(t)
+
+	t.Run("properties changes should not rebuild", func(t *testing.T) {
+		name := "java"
+		Expect(KamelRunWithID(operatorID, ns, "files/Java.java",
+			"--name", name,
+		).Execute()).To(Succeed())
+		Eventually(IntegrationPodPhase(ns, name), TestTimeoutLong).Should(Equal(corev1.PodRunning))
+		Eventually(IntegrationConditionStatus(ns, name, v1.IntegrationConditionReady), TestTimeoutShort).Should(Equal(corev1.ConditionTrue))
+		Eventually(IntegrationLogs(ns, name), TestTimeoutShort).Should(ContainSubstring("Magicstring!"))
+		integrationKit := IntegrationKit(ns, name)()
+
+		Expect(KamelRunWithID(operatorID, ns, "files/Java.java",
+			"--name", name,
+			"-p", "a=1",
+		).Execute()).To(Succeed())
+		Eventually(IntegrationPodPhase(ns, name), TestTimeoutShort).Should(Equal(corev1.PodRunning))
+		Eventually(IntegrationConditionStatus(ns, name, v1.IntegrationConditionReady), TestTimeoutShort).Should(Equal(corev1.ConditionTrue))
+		Eventually(IntegrationLogs(ns, name), TestTimeoutShort).Should(ContainSubstring("Magicstring!"))
+		Eventually(IntegrationKit(ns, name)).Should(Equal(integrationKit))
+	})
+
+	// Clean-up
+	Expect(Kamel("delete", "--all", "-n", ns).Execute()).To(Succeed())
+}

pkg/controller/integration/kits.go

@@ -199,8 +199,7 @@ func hasMatchingTraits(traitMap trait.Options, kitTraitMap trait.Options) (bool,
 	catalog := trait.NewCatalog(nil)
 
 	for _, t := range catalog.AllTraits() {
-		if t == nil || !t.InfluencesKit() {
-			// We don't store the trait configuration if the trait cannot influence the kit behavior
+		if t == nil {
 			continue
 		}
 
@@ -211,17 +210,17 @@ func hasMatchingTraits(traitMap trait.Options, kitTraitMap trait.Options) (bool,
 		if !ok1 && !ok2 {
 			continue
 		}
-		if !ok1 || !ok2 {
-			return false, nil
-		}
-		if ct, ok := t.(trait.ComparableTrait); ok {
-			// if it's match trait use its matches method to determine the match
-			if match, err := matchesComparableTrait(ct, it, kt); !match || err != nil {
-				return false, err
-			}
-		} else {
-			if !matchesTrait(it, kt) {
-				return false, nil
+
+		if t.InfluencesKit() && t.InfluencesBuild(it, kt) {
+			if ct, ok := t.(trait.ComparableTrait); ok {
+				// if it's match trait use its matches method to determine the match
+				if match, err := matchesComparableTrait(ct, it, kt); !match || err != nil {
+					return false, err
+				}
+			} else {
+				if !matchesTrait(it, kt) {
+					return false, nil
+				}
 			}
 		}
 	}

pkg/trait/builder.go

@@ -53,6 +53,11 @@ func (t *builderTrait) InfluencesKit() bool {
 	return true
 }
 
+// InfluencesBuild overrides base class method.
+func (t *builderTrait) InfluencesBuild(this, prev map[string]interface{}) bool {
+	return true
+}
+
 func (t *builderTrait) Configure(e *Environment) (bool, error) {
 	if e.IntegrationKit == nil || !pointer.BoolDeref(t.Enabled, true) {
 		return false, nil

pkg/trait/camel.go

@@ -58,6 +58,11 @@ func (t *camelTrait) InfluencesKit() bool {
 	return true
 }
 
+// InfluencesBuild only when the runtime has changed.
+func (t *camelTrait) InfluencesBuild(this, prev map[string]interface{}) bool {
+	return this["runtimeVersion"] != prev["runtimeVersion"]
+}
+
 func (t *camelTrait) Configure(e *Environment) (bool, error) {
 	if !pointer.BoolDeref(t.Enabled, true) {
 		return false, errors.New("trait camel cannot be disabled")

pkg/trait/quarkus.go

@@ -106,6 +106,11 @@ func (t *quarkusTrait) InfluencesKit() bool {
 	return true
 }
 
+// InfluencesBuild overrides base class method.
+func (t *quarkusTrait) InfluencesBuild(this, prev map[string]interface{}) bool {
+	return true
+}
+
 var _ ComparableTrait = &quarkusTrait{}
 
 func (t *quarkusTrait) Matches(trait Trait) bool {

pkg/trait/registry.go

@@ -53,6 +53,11 @@ func (t *registryTrait) InfluencesKit() bool {
 	return true
 }
 
+// InfluencesBuild overrides base class method.
+func (t *registryTrait) InfluencesBuild(this, prev map[string]interface{}) bool {
+	return true
+}
+
 func (t *registryTrait) Configure(e *Environment) (bool, error) {
 	// disabled by default
 	if e.IntegrationKit == nil || !pointer.BoolDeref(t.Enabled, false) {

pkg/trait/trait_types.go

@@ -69,6 +69,11 @@ type Trait interface {
 	// InfluencesKit determines if the trait has any influence on Integration Kits
 	InfluencesKit() bool
 
+	// InfluencesBuild defines a low level of granularity for those traits which influences the build.
+	// The trait can specify if any particular trait configuration influences a build or not.
+	// Note: You must override this method if you override `InfluencesKit()`
+	InfluencesBuild(this, prev map[string]interface{}) bool
+
 	// IsPlatformTrait marks all fundamental traits that allow the platform to work
 	IsPlatformTrait() bool
 
@@ -135,6 +140,12 @@ func (trait *BaseTrait) InfluencesKit() bool {
 	return false
 }
 
+// InfluencesBuild defines a low level of granularity for those traits which influences the build.
+// The trait can specify if any particular trait configuration influences a build or not.
+func (trait *BaseTrait) InfluencesBuild(this, prev map[string]interface{}) bool {
+	return false
+}
+
 // IsPlatformTrait marks all fundamental traits that allow the platform to work.
 func (trait *BaseTrait) IsPlatformTrait() bool {
 	return false