Fixing error thrown when unloading gun when there is no inventory ava…

…ilable (CleverRaven#48999)

* Adding unloaded gun to avoid
* Added unit test
* Unload partial ammo of wielded item without duplication

Signed-off-by: Lance Finfrock <lancewf@gmail.com>
Co-authored-by: actual-nh <74678550+actual-nh@users.noreply.github.com>
Co-authored-by: RoyBerube <royberube1965@gmail.com>

src/activity_actor.cpp

@@ -1704,7 +1704,7 @@ void unload_activity_actor::unload( Character &who, item_location &target )
         if( contained->ammo_type() == ammotype( "plutonium" ) ) {
             contained->charges /= PLUTONIUM_CHARGES;
         }
-        if( who.as_player()->add_or_drop_with_msg( *contained, true ) ) {
+        if( who.as_player()->add_or_drop_with_msg( *contained, true, &it ) ) {
             qty += contained->charges;
             remove_contained.push_back( contained );
             actually_unloaded = true;

src/character.cpp

@@ -3679,9 +3679,9 @@ units::mass Character::weight_capacity() const
     return ret;
 }
 
-bool Character::can_pickVolume( const item &it, bool ) const
+bool Character::can_pickVolume( const item &it, bool, const item *avoid ) const
 {
-    if( weapon.can_contain( it ) ) {
+    if( weapon.can_contain( it ) && ( avoid == nullptr || &weapon != avoid ) ) {
         return true;
     }
     for( const item &w : worn ) {
@@ -12820,7 +12820,7 @@ bool Character::add_or_drop_with_msg( item &it, const bool /*unloading*/, const
         liquid_handler::consume_liquid( it, 1, avoid );
         return it.charges <= 0;
     }
-    if( !this->can_pickVolume( it ) ) {
+    if( !this->can_pickVolume( it, false, avoid ) ) {
         put_into_vehicle_or_drop( *this, item_drop_reason::too_large, { it } );
     } else if( !this->can_pickWeight( it, !get_option<bool>( "DANGEROUS_PICKUPS" ) ) ) {
         put_into_vehicle_or_drop( *this, item_drop_reason::too_heavy, { it } );

src/character.h

@@ -1714,7 +1714,7 @@ class Character : public Creature, public visitable
         bool fun_to_read( const item &book ) const;
         int book_fun_for( const item &book, const Character &p ) const;
 
-        bool can_pickVolume( const item &it, bool safe = false ) const;
+        bool can_pickVolume( const item &it, bool safe = false, const item *avoid = nullptr ) const;
         bool can_pickWeight( const item &it, bool safe = true ) const;
         bool can_pickWeight_partial( const item &it, bool safe = true ) const;
         /**

tests/unload_naked_test.cpp

@@ -0,0 +1,88 @@
+#include <list>
+#include <memory>
+
+#include "avatar.h"
+#include "calendar.h"
+#include "catch/catch.hpp"
+#include "item.h"
+#include "map.h"
+#include "map_helpers.h"
+#include "optional.h"
+#include "player_helpers.h"
+#include "type_id.h"
+
+/**
+ * When a player has no open inventory to place unloaded bullets, but there is room in the gun being
+ * unloaded the bullets are dropped.
+ * issue# 29839
+ */
+
+TEST_CASE( "unload_revolver_naked_one_bullet", "[unload][nonmagzine]" )
+{
+    clear_avatar();
+    clear_map();
+
+    Character &dummy = get_player_character();
+    avatar &player_character = get_avatar();
+
+    // revolver with only one of six bullets
+    item revolver( "ruger_redhawk" );
+    revolver.ammo_set( revolver.ammo_default(), 1 );
+
+    // wield the revolver
+    REQUIRE( !player_character.is_armed( ) );
+    REQUIRE( player_character.wield( revolver ) );
+    REQUIRE( player_character.is_armed( ) );
+
+    CHECK( player_character.weapon.ammo_remaining() == 1 );
+
+    // Unload weapon
+    item_location revo_loc( dummy, &player_character.weapon );
+    player_character.moves = 100;
+    REQUIRE( player_character.unload( revo_loc ) );
+    player_character.activity.do_turn( player_character );
+
+    // No bullets in wielded gun
+    CHECK( player_character.weapon.ammo_remaining() == 0 );
+
+    // No bullets in inventory
+    const std::vector<item *> bullets = dummy.items_with( []( const item & item ) {
+        return item.is_ammo();
+    } );
+    CHECK( bullets.empty() );
+}
+
+TEST_CASE( "unload_revolver_naked_fully_loaded", "[unload][nonmagzine]" )
+{
+    clear_avatar();
+    clear_map();
+
+    Character &dummy = get_player_character();
+    avatar &player_character = get_avatar();
+
+    // revolver fully loaded
+    item revolver( "ruger_redhawk" );
+    revolver.ammo_set( revolver.ammo_default(), revolver.remaining_ammo_capacity() );
+
+    // wield the revolver
+    REQUIRE( !player_character.is_armed( ) );
+    REQUIRE( player_character.wield( revolver ) );
+    REQUIRE( player_character.is_armed( ) );
+
+    CHECK( player_character.weapon.remaining_ammo_capacity() == 0 );
+
+    // Unload weapon
+    item_location revo_loc( dummy, &player_character.weapon );
+    player_character.moves = 100;
+    REQUIRE( player_character.unload( revo_loc ) );
+    player_character.activity.do_turn( player_character );
+
+    // No bullets in wielded gun
+    CHECK( player_character.weapon.ammo_remaining() == 0 );
+
+    // No bullets in inventory
+    const std::vector<item *> bullets = dummy.items_with( []( const item & item ) {
+        return item.is_ammo();
+    } );
+    CHECK( bullets.empty() );
+}