AutoMapping: Match in order by default, when input regions are defined

This improves compatibility with AutoMapping rules written for older
versions of Tiled.

Closes mapeditor#3559

NEWS.md

@@ -3,6 +3,7 @@
 * Added action search popup on Ctrl+Shift+P (with dogboydog, #3449)
 * Added file system actions also for tileset image based tilesets (#3448)
 * Fixed new layer names to be always unique (by Logan Higinbotham, #3452)
+* AutoMapping: Match in order by default, when input regions are defined (#3559)
 * Scripting: Added Object.setColorProperty and Object.setFloatProperty (#3423)
 * Scripting: Added tiled.projectFilePath
 * Scripting: Added TileMap.toImage (#3519)

src/tiled/automapper.cpp

@@ -556,6 +556,10 @@ void AutoMapper::setupRules()
                     regionInput |= inputLayer.tileLayer->region();
             }
         }
+    } else if (!mOptions.matchInOrder.has_value()) {
+        // For backwards compatibility, when the input regions have been
+        // explicitly defined, we default MatchInOrder to true.
+        mOptions.matchInOrder = true;
     }
 
     // When no output regions have been defined at all, derive them from the
@@ -985,7 +989,7 @@ void AutoMapper::autoMap(const QRegion &where,
 
     ApplyContext applyContext(appliedRegion);
 
-    if (mOptions.matchInOrder) {
+    if (mOptions.matchInOrder.value_or(false)) {
         for (const Rule &rule : mRules) {
             if (rule.options.disabled)
                 continue;

src/tiled/automapper.h

@@ -35,6 +35,7 @@
 #include <QVector>
 
 #include <memory>
+#include <optional>
 #include <type_traits>
 #include <unordered_map>
 #include <vector>
@@ -260,7 +261,7 @@ class TILED_EDITOR_EXPORT AutoMapper : public QObject
         /**
          * Determines whether the rules on the map need to be matched in order.
          */
-        bool matchInOrder = false;
+        std::optional<bool> matchInOrder;
 
         /**
          * This variable determines, how many overlapping tiles should be used.