Added cleanup for unsaved submaps

src/editmap.cpp

@@ -2209,12 +2209,9 @@ void editmap::edit_mapgen()
 /*
  * Special voodoo sauce required to cleanse vehicles and caches to prevent debugmsg loops when re-applying mapgen.
  */
-void editmap::cleartmpmap( tinymap &tmpmap ) const
+void editmap::cleartmpmap( smallmap &tmpmap ) const
 {
-    for( submap *&smap : tmpmap.grid ) {
-        delete smap;
-        smap = nullptr;
-    }
+    tmpmap.delete_unmerged_submaps();
 
     for( int z = -OVERMAP_DEPTH; z <= OVERMAP_HEIGHT; z++ ) {
         level_cache &ch = tmpmap.get_cache( z );

src/editmap.h

@@ -18,6 +18,7 @@
 class Creature;
 class field;
 class map;
+class smallmap;
 class tinymap;
 class ui_adaptor;
 class uilist;
@@ -60,7 +61,7 @@ class editmap
         void edit_itm();
         void edit_critter( Creature &critter );
         void edit_mapgen();
-        void cleartmpmap( tinymap &tmpmap ) const;
+        void cleartmpmap( smallmap &tmpmap ) const;
         void mapgen_preview( const real_coords &tc, uilist &gmenu );
         vehicle *mapgen_veh_query( const tripoint_abs_omt &omt_tgt );
         bool mapgen_veh_destroy( const tripoint_abs_omt &omt_tgt, vehicle *car_target );

src/map.h

@@ -1864,6 +1864,9 @@ class map
         // The code relies on the submap coordinate falling on omt boundaries, so taking a
         // tripoint_abs_omt coordinate guarantees this will be fulfilled.
         void generate( const tripoint_abs_omt &p, const time_point &when, bool save_results );
+        // Used when contents has been generated by 'generate' with save_results = false to dispose of
+        // submaps that aren't present in the map buffer. This is done to avoid memory leaks.
+        void delete_unmerged_submaps();
         void place_spawns( const mongroup_id &group, int chance,
                            const point_bub_ms &p1, const point_bub_ms &p2, int z_level, float density,
                            bool individual = false, bool friendly = false,
@@ -2559,6 +2562,7 @@ class tinymap : private map
         using map::is_main_cleanup_queued;
         using map::main_cleanup_override;
         using map::generate;
+        using map::delete_unmerged_submaps;
         void place_spawns( const mongroup_id &group, int chance,
                            const point_omt_ms &p1, const point_omt_ms &p2, const int z_level, float density,
                            bool individual = false, bool friendly = false,

src/mapgen.cpp

@@ -400,6 +400,28 @@ void map::generate( const tripoint_abs_omt &p, const time_point &when, bool save
     set_abs_sub( p_sm_base );
 }
 
+void map::delete_unmerged_submaps()
+{
+    tripoint_abs_sm sm_base = get_abs_sub();
+
+    for( size_t index = 0; index < grid.size(); index++ ) {
+        tripoint offset;
+        const int ix = static_cast<int>( index );
+
+        // This is the inverse of get_nonant.
+        if( zlevels ) {
+            offset = { ( ix / OVERMAP_LAYERS ) % my_MAPSIZE, ix / OVERMAP_LAYERS / my_MAPSIZE, ix % OVERMAP_LAYERS - OVERMAP_DEPTH };
+        } else {
+            offset = { ix % my_MAPSIZE, ix / my_MAPSIZE, sm_base.z()};
+        }
+
+        if( grid[index] != nullptr && MAPBUFFER.lookup_submap( sm_base.xy() + offset ) != grid[index] ) {
+            delete grid[index];
+            grid[index] = nullptr;
+        }
+    }
+}
+
 void mapgen_function_builtin::generate( mapgendata &mgd )
 {
     ( *fptr )( mgd );

tests/overmap_test.cpp

@@ -459,6 +459,7 @@ TEST_CASE( "overmap_terrain_coverage", "[overmap][slow]" )
                         sample_size = goal_samples - p.second.samples;
                         p.second.found = true;
                     }
+                    tm.delete_unmerged_submaps();
                 }
             } );
             p.second.samples = goal_samples;