Require plugin-plugin >= 1.7 for pom:validate

git-svn-id: https://svn.apache.org/repos/asf/maven/maven-1/plugins/trunk@350058 13f79535-47bb-0310-9956-ffa450edef68

pom/plugin.jelly

@@ -27,7 +27,8 @@
   xmlns:ant="jelly:ant"
   xmlns:x="jelly:xml"
   xmlns:log="jelly:log"
-  xmlns:artifact="artifact">
+  xmlns:artifact="artifact"
+  xmlns:assert="assert">
 
   <!-- set up pom tag library -->
   <d:taglib uri="pom">
@@ -61,6 +62,12 @@
     name="pom:validate"
     description="Validate the Maven XML project descriptor">
 
+    <assert:assertPluginAvailable
+        groupId="maven"
+        artifactId="maven-plugin-plugin"
+        minRelease="1.7"
+        neededBy="${plugin.artifactId}"/>
+
     <j:set var="xsd"
         value="${plugin.resources}/xsd/pom-strict-${pom.pomVersion}.xsd"/>