From 886e55207713a015c462986b39b1bd10e626d47d Mon Sep 17 00:00:00 2001
From: Lee Martin <lee.martin@pliminus.co.uk>
Date: Sat, 16 Nov 2019 13:04:43 +0000
Subject: [PATCH] Remove failed craft when losing last component Currently, in
 progress crafts that lose their last component still exist, but with a volume
 of 0 as there is nothing in them. I've added this fix where if a player/npc
 bungles a craft and loses the last component of it (and the craft had
 components to start with), the craft item is removed from the game. fixes
 #34072

---
 src/activity_handlers.cpp |  9 ++++++++-
 src/crafting.cpp          | 11 ++++++++---
 src/item.h                |  3 ++-
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/activity_handlers.cpp b/src/activity_handlers.cpp
index f8069c706ed51..0bab9943bf2d6 100644
--- a/src/activity_handlers.cpp
+++ b/src/activity_handlers.cpp
@@ -3481,7 +3481,14 @@ void activity_handlers::craft_do_turn( player_activity *act, player *p )
             }
         }
     } else if( craft->item_counter >= craft->get_next_failure_point() ) {
-        craft->handle_craft_failure( *p );
+        bool destroy = craft->handle_craft_failure( *p );
+        // If the craft needs to be destroyed, do it and stop crafting.
+        if( destroy ) {
+            p->add_msg_player_or_npc( _( "There is nothing left of the %s to craft from." ),
+                                      _( "There is nothing left of the %s <npcname> was crafting." ), craft->tname() );
+            act->targets.front().remove_item();
+            p->cancel_activity();
+        }
     }
 }
 
diff --git a/src/crafting.cpp b/src/crafting.cpp
index 49ead82965c45..0ee97d04e6dcc 100644
--- a/src/crafting.cpp
+++ b/src/crafting.cpp
@@ -986,15 +986,15 @@ static void destroy_random_component( item &craft, const player &crafter )
                                    _( "<npcname> messes up and destroys the %s" ), destroyed.tname() );
 }
 
-void item::handle_craft_failure( player &crafter )
+bool item::handle_craft_failure( player &crafter )
 {
     if( !is_craft() ) {
         debugmsg( "handle_craft_failure() called on non-craft '%s.'  Aborting.", tname() );
-        return;
+        return false;
     }
 
     const double success_roll = crafter.crafting_success_roll( get_making() );
-
+    const int starting_components = this->components.size();
     // Destroy at most 75% of the components, always a chance of losing 1 though
     const size_t max_destroyed = std::max<size_t>( 1, components.size() * 3 / 4 );
     for( size_t i = 0; i < max_destroyed; i++ ) {
@@ -1008,6 +1008,10 @@ void item::handle_craft_failure( player &crafter )
         }
         destroy_random_component( *this, crafter );
     }
+    if( starting_components > 0 && this->components.empty() ) {
+        // The craft had components and all of them were destroyed.
+        return true;
+    }
 
     // Minimum 25% progress lost, average 35%.  Falls off exponentially
     // Loss is scaled by the success roll
@@ -1024,6 +1028,7 @@ void item::handle_craft_failure( player &crafter )
     if( !crafter.can_continue_craft( *this ) ) {
         crafter.cancel_activity();
     }
+    return false;
 }
 
 requirement_data item::get_continue_reqs() const
diff --git a/src/item.h b/src/item.h
index c0a4255d1ccf6..74f9f9e2aa87c 100644
--- a/src/item.h
+++ b/src/item.h
@@ -1992,8 +1992,9 @@ class item : public visitable<item>
          * Handle failure during crafting.
          * Destroy components, lose progress, and set a new failure point.
          * @param crafter the crafting player.
+         * @return whether the craft being worked on should be entirely destroyed
          */
-        void handle_craft_failure( player &crafter );
+        bool handle_craft_failure( player &crafter );
 
         /**
          * Returns requirement data representing what is needed to resume work on an in progress craft.