#47 Maven plugin, fixed NPE for empty global variable value

Author: raydac

jcp-tests/jcp-test-maven/pom.xml

@@ -74,6 +74,7 @@
             <configuration>
               <useTestSources>true</useTestSources>
               <vars>
+                <empty.null.variable></empty.null.variable>
                 <some.test.global.test>Some Test</some.test.global.test>
               </vars>
             </configuration>

jcp-tests/jcp-test-maven/src/main/java/com/igormaznitsa/jcp/it/maven/Main.java

@@ -12,6 +12,10 @@ public Main(){
       throw new Error("Must be MainTwo but detected"+this.getClass().getName());
     }
 
+    //#if empty.null.variable
+    throw new Error("Must not be presented because variable must be recognized as false");
+    //#endif
+
     final String test = /*$"\""+some.test.global+"\";"$*/ /*-*/ "";
 
     if ("Some Test Global Value".equals(test)){

jcp/src/main/java/com/igormaznitsa/jcp/maven/PreprocessMojo.java

@@ -363,11 +363,11 @@ PreprocessorContext makePreprocessorContext() throws IOException {
 
     if (this.project != null) {
       final MavenPropertiesImporter mavenPropertiesImporter =
-              new MavenPropertiesImporter(context,
-                      this.project,
-                      this.session,
-                      isVerbose() || getLog().isDebugEnabled()
-              );
+          new MavenPropertiesImporter(context,
+              this.project,
+              this.session,
+              isVerbose() || getLog().isDebugEnabled()
+          );
       context.registerSpecialVariableProcessor(mavenPropertiesImporter);
     }
 
@@ -405,12 +405,25 @@ PreprocessorContext makePreprocessorContext() throws IOException {
 
     this.configFiles.forEach(x -> context.registerConfigFile(new File(x)));
 
-    // process global vars
-    this.getVars().forEach((key, value) -> {
-      getLog().debug(String.format("Register global var: '%s' <- '%s'", key, value));
-      context.setGlobalVariable(key, Value.recognizeRawString(value));
-    });
-
+    // register global vars
+    this.getVars().entrySet().stream()
+        .filter(e -> {
+          final String key = e.getKey();
+          final String value = e.getValue();
+          if (value == null) {
+            getLog().warn(String.format(
+                "Global var '%s' ignored for null value (may be its content is empty in POM)",
+                key));
+            return false;
+          } else {
+            return true;
+          }
+        })
+        .forEach(e -> {
+          getLog().debug(
+              String.format("Register global var: '%s' <- '%s'", e.getKey(), e.getValue()));
+          context.setGlobalVariable(e.getKey(), Value.recognizeRawString(e.getValue()));
+        });
     return context;
   }