[MNG-7804] Ability to order plugin executions using the priority xml element (#1147)

api/maven-api-model/src/main/mdo/maven.mdo

@@ -2634,7 +2634,7 @@
         </field>
         <field xml.transient="true">
           <name>priority</name>
-          <version>4.0.0+</version>
+          <version>4.0.0</version>
           <type>int</type>
           <description>
             <![CDATA[
@@ -2645,6 +2645,15 @@
             ]]>
           </description>
         </field>
+        <field>
+          <name>priority</name>
+          <version>4.1.0+</version>
+          <type>int</type>
+          <description>The priority of this execution compared to other executions which are bound to the same phase.
+            Executions derived from the default lifecycle have a negative priority by default so that they are executed
+            before any custom plugin executions.
+          </description>
+        </field>
         <field>
           <name>goals</name>
           <version>4.0.0+</version>

maven-model/pom.xml

@@ -90,10 +90,16 @@ under the License.
             <id>modello-site-docs</id>
             <goals>
               <goal>xdoc</goal>
-              <goal>xsd</goal>
             </goals>
             <phase>pre-site</phase>
           </execution>
+          <execution>
+            <id>modello-schema</id>
+            <goals>
+              <goal>xsd</goal>
+            </goals>
+            <phase>generate-resources</phase>
+          </execution>
           <execution>
             <id>model-v3</id>
             <goals>

maven-model/src/test/java/org/apache/maven/model/v4/MavenModelVersionTest.java

@@ -19,8 +19,12 @@
 package org.apache.maven.model.v4;
 
 import java.io.InputStream;
+import java.util.Collections;
 
+import org.apache.maven.api.model.Build;
 import org.apache.maven.api.model.Model;
+import org.apache.maven.api.model.Plugin;
+import org.apache.maven.api.model.PluginExecution;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 
@@ -59,4 +63,13 @@ class MavenModelVersionTest {
         Model m = model.withPreserveModelVersion(true);
         assertEquals("4.1.0", new MavenModelVersion().getModelVersion(m));
     }
+
+    @Test
+    void testV4V4ModelPriority() {
+        Model m = model.withBuild(Build.newInstance()
+                .withPlugins(Collections.singleton(Plugin.newInstance()
+                        .withExecutions(Collections.singleton(
+                                PluginExecution.newInstance().withPriority(5))))));
+        assertEquals("4.1.0", new MavenModelVersion().getModelVersion(m));
+    }
 }