[MPH-185] Restore location format for effective-pom

Was changed by accident in 4f9e3af

Author: slawekjaranowski

src/it/projects/effective-pom-verbose/verify.groovy

@@ -20,4 +20,5 @@
 String content = new File( basedir, "build.log" ).text
 
 // comments in the same line
-assert content.contains( "<groupId>org.apache.maven.its.help</groupId>  <!-- " )
+assert content.contains( "<groupId>org.apache.maven.its.help</groupId>  <!-- org.apache.maven.its.help:test:1.0-SNAPSHOT," )
+assert content.contains( "<url>https://maven.apache.org/plugins/test/</url>  <!-- org.apache.maven.plugins:maven-plugins:33, line 37 -->" )

src/main/java/org/apache/maven/plugins/help/EffectivePomMojo.java

@@ -208,10 +208,11 @@ private static class InputLocationStringFormatter extends InputLocation.StringFo
         public String toString(InputLocation location) {
             InputSource source = location.getSource();
 
-            String s = source.getLocation(); // by default, display the path
+            String s = source.getModelId(); // by default, display modelId
 
-            if (s == null || s.trim().isEmpty()) {
-                s = source.getModelId();
+            if (StringUtils.isBlank(s) || s.contains("[unknown-version]")) {
+                // unless it is blank or does not provide version information
+                s = source.toString();
             }
 
             return '}' + s + ((location.getLineNumber() >= 0) ? ", line " + location.getLineNumber() : "") + ' ';