Merge branch 'master' into jgrpp

# Conflicts:
#	.github/workflows/ci-build.yml
#	.github/workflows/release-linux.yml
#	.github/workflows/release-macos.yml
#	.github/workflows/release-windows.yml
#	.gitignore
#	COMPILING.md
#	src/company_gui.cpp
#	src/date_gui.cpp
#	src/engine.cpp
#	src/engine_func.h
#	src/fileio.cpp
#	src/linkgraph/linkgraph_gui.h
#	src/newgrf_debug_gui.cpp
#	src/newgrf_gui.cpp
#	src/order_gui.cpp
#	src/osk_gui.cpp
#	src/rail_gui.cpp
#	src/road_gui.cpp
#	src/script/api/script_event_types.hpp
#	src/sl/oldloader_sl.cpp
#	src/smallmap_gui.cpp
#	src/station_cmd.cpp
#	src/toolbar_gui.cpp
#	src/town_gui.cpp
#	src/transparency_gui.cpp
#	src/vehicle_gui.cpp
#	src/widget.cpp
#	src/widget_type.h
#	src/widgets/dropdown.cpp
#	src/widgets/dropdown_func.h
#	src/widgets/dropdown_type.h
#	src/widgets/group_widget.h
#	src/widgets/vehicle_widget.h
#	src/window.cpp
#	src/window_gui.h
#	src/window_type.h

src/script/api/ai_changelog.hpp

@@ -24,6 +24,9 @@
  * API removals:
  * \li AIError::ERR_PRECONDITION_TOO_MANY_PARAMETERS, that error is never returned anymore.
  *
+ * Other changes:
+ * \li AIVehicleList accepts an optional filter function
+ *
  * \b 13.0
  *
  * API additions:

src/script/api/game_changelog.hpp

@@ -84,6 +84,9 @@
  * API removals:
  * \li GSError::ERR_PRECONDITION_TOO_MANY_PARAMETERS, that error is never returned anymore.
  *
+ * Other changes:
+ * \li GSVehicleList accepts an optional filter function
+ *
  * \b 13.0
  *
  * API additions:

src/script/api/script_event_types.hpp

@@ -925,7 +925,7 @@ public:
 	 * @param number The windownumber that was clicked.
 	 * @param widget The widget in the window that was clicked.
 	 */
-	ScriptEventWindowWidgetClick(ScriptWindow::WindowClass window, uint32 number, uint8 widget) :
+	ScriptEventWindowWidgetClick(ScriptWindow::WindowClass window, uint32_t number, WidgetID widget) :
 		ScriptEvent(ET_WINDOW_WIDGET_CLICK),
 		window(window),
 		number(number),
@@ -956,12 +956,12 @@ public:
 	 * Get the number of the widget that was clicked.
 	 * @return The number of the clicked widget.
 	 */
-	uint8 GetWidgetNumber() { return this->widget; }
+	int GetWidgetNumber() { return this->widget; }
 
 private:
 	ScriptWindow::WindowClass window; ///< Window of the click.
-	uint32 number;                    ///< Number of the click.
-	uint8 widget;                     ///< Widget of the click.
+	uint32_t number;                  ///< Number of the click.
+	WidgetID widget;                  ///< Widget of the click.
 };
 
 /**

src/script/api/script_vehiclelist.cpp

@@ -18,12 +18,78 @@
 
 #include "../../safeguards.h"
 
-ScriptVehicleList::ScriptVehicleList()
+ScriptVehicleList::ScriptVehicleList(HSQUIRRELVM vm)
 {
 	EnforceDeityOrCompanyModeValid_Void();
-	for (const Vehicle *v : Vehicle::Iterate()) {
-		if ((v->owner == ScriptObject::GetCompany() || ScriptCompanyMode::IsDeity()) && (v->IsPrimaryVehicle() || (v->type == VEH_TRAIN && ::Train::From(v)->IsFreeWagon()))) this->AddItem(v->index);
+
+	int nparam = sq_gettop(vm) - 1;
+	if (nparam >= 1) {
+		/* Make sure the filter function is really a function, and not any
+		 * other type. It's parameter 2 for us, but for the user it's the
+		 * first parameter they give. */
+		SQObjectType valuator_type = sq_gettype(vm, 2);
+		if (valuator_type != OT_CLOSURE && valuator_type != OT_NATIVECLOSURE) {
+			throw sq_throwerror(vm, "parameter 1 has an invalid type (expected function)");
+		}
+
+		/* Push the function to call */
+		sq_push(vm, 2);
 	}
+
+	/* Don't allow docommand from a Valuator, as we can't resume in
+	 * mid C++-code. */
+	bool backup_allow = ScriptObject::GetAllowDoCommand();
+	ScriptObject::SetAllowDoCommand(false);
+
+	for (const Vehicle *v : Vehicle::Iterate()) {
+		if (v->owner != ScriptObject::GetCompany() && !ScriptCompanyMode::IsDeity()) continue;
+		if (!v->IsPrimaryVehicle() && !(v->type == VEH_TRAIN && ::Train::From(v)->IsFreeWagon())) continue;
+
+		if (nparam < 1) {
+			/* No filter, just add the item. */
+			this->AddItem(v->index);
+			continue;
+		}
+
+		/* Push the root table as instance object, this is what squirrel does for meta-functions. */
+		sq_pushroottable(vm);
+		/* Push all arguments for the valuator function. */
+		sq_pushinteger(vm, v->index);
+		for (int i = 0; i < nparam - 1; i++) {
+			sq_push(vm, i + 3);
+		}
+
+		/* Call the function. Squirrel pops all parameters and pushes the return value. */
+		if (SQ_FAILED(sq_call(vm, nparam + 1, SQTrue, SQTrue))) {
+			ScriptObject::SetAllowDoCommand(backup_allow);
+			throw sq_throwerror(vm, "failed to run filter");
+		}
+
+		/* Retrieve the return value */
+		switch (sq_gettype(vm, -1)) {
+			case OT_BOOL: {
+				SQBool add;
+				sq_getbool(vm, -1, &add);
+				if (add) this->AddItem(v->index);
+				break;
+			}
+
+			default: {
+				ScriptObject::SetAllowDoCommand(backup_allow);
+				throw sq_throwerror(vm, "return value of filter is not valid (not bool)");
+			}
+		}
+
+		/* Pop the return value. */
+		sq_poptop(vm);
+	}
+
+	if (nparam >= 1) {
+		/* Pop the filter function */
+		sq_poptop(vm);
+	}
+
+	ScriptObject::SetAllowDoCommand(backup_allow);
 }
 
 ScriptVehicleList_Station::ScriptVehicleList_Station(StationID station_id)

src/script/api/script_vehiclelist.hpp

@@ -20,7 +20,32 @@
  */
 class ScriptVehicleList : public ScriptList {
 public:
+#ifdef DOXYGEN_API
 	ScriptVehicleList();
+
+	/**
+	 * Apply a filter when building the list.
+	 * @param filter_function The function which will be doing the filtering.
+	 * @param params The params to give to the filters (minus the first param,
+	 *  which is always the index-value).
+	 * @note You can write your own filters and use them. Just remember that
+	 *  the first parameter should be the index-value, and it should return
+	 *  a bool.
+	 * @note Example:
+	 *  ScriptVehicleList(ScriptVehicle.IsInDepot);
+	 *  function IsType(vehicle_id, type)
+	 *  {
+	 *    return ScriptVehicle.GetVehicleType(vehicle_id) == type;
+	 *  }
+	 *  ScriptVehicleList(IsType, ScriptVehicle.VT_ROAD);
+	 */
+	ScriptVehicleList(void *filter_function, int params, ...);
+#else
+	/**
+	 * The constructor wrapper from Squirrel.
+	 */
+	ScriptVehicleList(HSQUIRRELVM vm);
+#endif
 };
 
 /**