Improved queryMapValue to return defaultValue instead of null

worldguard-core/src/main/java/com/sk89q/worldguard/protection/FlagValueCalculator.java

@@ -268,7 +268,7 @@ public <V, K> V queryMapValue(@Nullable RegionAssociable subject, MapFlag<K, V>
             if (effectiveValue != null) {
                 minimumPriority = getPriority(region);
                 consideredValues.put(region, effectiveValue);
-            } else {
+            } else if (fallback != null) {
                 effectiveValue = getEffectiveFlag(region, fallback, subject);
                 if (effectiveValue != null) {
                     minimumPriority = getPriority(region);
@@ -278,9 +278,17 @@ public <V, K> V queryMapValue(@Nullable RegionAssociable subject, MapFlag<K, V>
 
             addParents(ignoredParents, region);
         }
-        V finalValue = flag.getValueFlag().chooseValue(consideredValues.values());
+
-        if (finalValue == null) return fallback.chooseValue(fallbackValues.values());
+
-        return finalValue;
+        if (consideredValues.isEmpty()) {
+            if (fallback != null && !fallbackValues.isEmpty()) {
+                return fallback.chooseValue(fallbackValues.values());
+            }
+            V defaultValue = flag.getValueFlag().getDefault();
+            return defaultValue != null ? defaultValue : fallback != null ? fallback.getDefault() : null;
+        }
+
+        return flag.getValueFlag().chooseValue(consideredValues.values());
     }
 
     @Nullable

worldguard-core/src/main/java/com/sk89q/worldguard/protection/regions/RegionQuery.java

@@ -173,6 +173,56 @@ public boolean testBuild(Location location, RegionAssociable associable, StateFl
                 queryState(location, associable, flag)));
     }
 
+    /**
+     * Returns true if the BUILD flag allows the action in the location, but it
+     * can be overridden by a list of other flags. The BUILD flag will not
+     * override the other flags, but the other flags can override BUILD. If
+     * neither BUILD or any of the flags permit the action, then false will
+     * be returned.
+     *
+     * <p>Use this method when checking flags that are related to build
+     * protection. For example, lighting fire in a region should not be
+     * permitted unless the player is a member of the region or the
+     * LIGHTER flag allows it. However, the LIGHTER flag should be able
+     * to allow lighting fires even if BUILD is set to DENY.</p>
+     *
+     * <p>This method does include parameters for a {@link MapFlag}.</p>
+     *
+     * <p>How this method works (BUILD can be overridden by other flags but
+     * not the other way around) is inconsistent, but it's required for
+     * legacy reasons.</p>
+     *
+     * <p>This method does not check the region bypass permission. That must
+     * be done by the calling code.</p>
+     *
+     * @param location the location
+     * @param associable an optional associable
+     * @param mapFlag the MapFlag
+     * @param key the key for the MapFlag
+     * @param fallback the fallback flag for MapFlag
+     * @param flag the flags
+     * @return true if the result was {@code ALLOW}
+     * @see RegionResultSet#queryValue(RegionAssociable, Flag)
+     */
+    public <K> boolean testBuild(Location location, RegionAssociable associable, MapFlag<K, State> mapFlag, K key,
+                                 @Nullable StateFlag fallback, StateFlag... flag) {
+        if (mapFlag == null)
+            return testBuild(location, associable, flag);
+
+        if (flag.length == 0) {
+            return StateFlag.test(StateFlag.combine(
+                    StateFlag.denyToNone(queryState(location, associable, Flags.BUILD)),
+                    queryMapValue(location, associable, mapFlag, key, fallback)
+            ));
+        }
+
+        return StateFlag.test(StateFlag.combine(
+                StateFlag.denyToNone(queryState(location, associable, Flags.BUILD)),
+                queryMapValue(location, associable, mapFlag, key, fallback),
+                queryState(location, associable, flag)
+        ));
+    }
+
     /**
      * Test whether the (effective) value for a list of state flags equals
      * {@code ALLOW}.
@@ -345,6 +395,34 @@ public <V, K> V queryMapValue(Location location, @Nullable RegionAssociable subj
         return getApplicableRegions(location).queryMapValue(subject, flag, key);
     }
 
+    /**
+     * Get the effective value for a key in a {@link MapFlag}. If there are multiple values
+     * (for example, if there are multiple regions with the same priority
+     * but with different farewell messages set, there would be multiple
+     * completing values), then the selected (or "winning") value will be undefined.
+     *
+     * <p>A subject can be provided that is used to determine whether the value
+     * of a flag on a particular region should be used. For example, if a
+     * flag's region group is set to {@link RegionGroup#MEMBERS} and the given
+     * subject is not a member, then the region would be skipped when
+     * querying that flag. If {@code null} is provided for the subject, then
+     * only flags that use {@link RegionGroup#ALL},
+     * {@link RegionGroup#NON_MEMBERS}, etc. will apply.</p>
+     *
+     * <p>It's possible to provide a fallback flag for the case when the key doesn't
+     * exist in the {@link MapFlag}.</p>
+     *
+     * @param subject an optional subject, which would be used to determine the region group to apply
+     * @param flag the flag of type {@link MapFlag}
+     * @param key the key for the map flag
+     * @param fallback the fallback flag
+     * @return a value, which could be {@code null}
+     */
+    @Nullable
+    public <V, K> V queryMapValue(Location location, @Nullable RegionAssociable subject, MapFlag<K, V> flag, K key, Flag<V> fallback) {
+        return getApplicableRegions(location).queryMapValue(subject, flag, key, fallback);
+    }
+
     /**
      * Get the effective values for a flag, returning a collection of all
      * values. It is up to the caller to determine which value, if any,