add verbose checking and feedback for ScriptParams usage

engine-core/src/main/java/io/nosqlbench/engine/core/script/Scenario.java

@@ -47,6 +47,7 @@ import java.util.stream.Collectors;
 public class Scenario implements Callable<ScenarioResult> {
 
     private static final Logger logger = (Logger) LoggerFactory.getLogger(Scenario.class);
+
     private static final ScriptEngineManager engineManager = new ScriptEngineManager();
     private final List<String> scripts = new ArrayList<>();
     private ScriptEngine scriptEngine;

engine-core/src/main/java/io/nosqlbench/engine/core/script/ScriptParams.java

@@ -17,23 +17,72 @@
 
 package io.nosqlbench.engine.core.script;
 
+import ch.qos.logback.classic.Logger;
+import io.nosqlbench.nb.api.errors.BasicError;
+import org.slf4j.LoggerFactory;
+
 import java.util.HashMap;
 import java.util.Map;
+import java.util.stream.Collectors;
 
-public class ScriptParams extends HashMap<String,String> {
+public class ScriptParams extends HashMap<String, String> {
 
-    public Map<String,String> withOverrides(Map<String,String> overrides) {
+    private static final Logger logger = (Logger) LoggerFactory.getLogger(ScriptParams.class);
-        HashMap<String,String> result = new HashMap<>();
+
+    public Map<String, String> withOverrides(Map<String, String> overrides) {
+        if (overrides == null) {
+            logger.warn("A null map was provided to withOverrides. This could be a bug in your script.");
+            overrides=Map.of();
+        }
+        checkForNulls("params", "calling withOverrides", this);
+        checkForNulls("overrides", "calling withOverrides", overrides);
+        HashMap<String, String> result = new HashMap<>();
         result.putAll(this);
         result.putAll(overrides);
         return result;
     }
 
-    public Map<String,String> withDefaults(Map<String,String> defaults) {
+    public Map<String, String> withDefaults(Map<String, String> defaults) {
-        HashMap<String,String> result = new HashMap<>();
+        if (defaults == null) {
+            logger.warn("A null map was provided to withDefaults. This could be a bug in your script.");
+            defaults=Map.of();
+        }
+        HashMap<String, String> result = new HashMap<>();
+        checkForNulls("params", "calling withDefaults", this);
+        checkForNulls("defaults", "calling withDefaults", defaults);
         result.putAll(defaults);
         result.putAll(this);
         return result;
     }
 
+    private static void checkForNulls(String name, String action, Map<String, String> map) {
+        for (String s : map.keySet()) {
+            if (s == null) {
+                printMapToLog(name,map);
+                throw new BasicError("Found a null key in " + name + " while " + action + ". Please ensure that you " +
+                    "only provide non-null keys and values in parameter maps.");
+            } else if (map.get(s) == null) {
+                printMapToLog(name,map);
+                throw new BasicError("Found a null value for key '" + s + "' in " + name + " while " + action + ". " +
+                    "Please ensure you provide non-null keys and values in parameter maps.");
+            }
+        }
+    }
+
+    private static void printMapToLog(String name, Map<String, String> map) {
+        logger.info("contents of map '" + name + "':");
+        String mapdetail = map.entrySet()
+            .stream()
+            .map(e -> valueOf(e.getKey()) + ":" + valueOf(e.getValue()))
+            .collect(Collectors.joining(","));
+        logger.info(mapdetail);
+    }
+
+    private static String valueOf(Object o) {
+        if (o == null) {
+            return "NULL";
+        }
+        return String.valueOf(o);
+    }
+
 }

engine-core/src/test/java/io/nosqlbench/engine/core/script/ScriptParamsTest.java

@@ -0,0 +1,23 @@
+package io.nosqlbench.engine.core.script;
+
+import io.nosqlbench.nb.api.errors.BasicError;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class ScriptParamsTest {
+
+    @Test(expected = BasicError.class)
+    public void testThatNullOverridesKeyThrowsBasicError() {
+        ScriptParams p = new ScriptParams();
+        p.putAll(Map.of("a","b"));
+        p.withDefaults(Map.of("c","d"));
+        HashMap<String, String> overrides = new HashMap<>();
+        overrides.put(null,"test");
+        p.withOverrides(overrides);
+    }
+
+}