Fix mining using a pickaxe always causes an error

[osuphobia]

Summary

Bugfixes "Fix mining using a pickaxe always causes an error"

Purpose of change

Fix #77865

Describe the solution

Use a better way by andrei8l to check if the tool disappered during mining.

Testing

Loaded the save from #76783 , game did not crash when earthshaper's pickaxe expired during mining.
Using normal pickaxes and jackhammers also didn't cause an error.

Additional context

[andrei8l]

I don't think this is correct. Items that use charges as fuel are NOT count_by_charges(). That being said, I am not aware of any mining tool that uses charges. magiclysm pickaxes (?)

[osuphobia]

I don't think this is correct. Items that use charges as fuel are NOT count_by_charges(). That being said, I am not aware of any mining tool that uses charges. magiclysm pickaxes (?)

You are right, I remembered it wrong.
I'll check if craft_has_charges() works.

[andrei8l]

Try this:

diff --git a/src/activity_handlers.cpp b/src/activity_handlers.cpp
index 5ab4240c1e..1c7b07a894 100644
--- a/src/activity_handlers.cpp
+++ b/src/activity_handlers.cpp
@@ -1869,12 +1869,10 @@ void activity_handlers::pickaxe_finish( player_activity *act, Character *you )
                                 _( "<npcname> finishes digging." ) );
     here.destroy( pos, true );
     if( !act->targets.empty() ) {
-        item &it = *act->targets.front();
-        if( it.is_null() || it.charges <= 0 ) {
-            debugmsg( "pickaxe expired during mining" );
-            return;
+        item_location it = act->targets.front();
+        if( it ) {
+            you->consume_charges( *it, it->ammo_required() );
         }
-        you->consume_charges( it, it.ammo_required() );
     } else {
         debugmsg( "pickaxe activity targets empty" );
     }

I can't test it atm. The original fix was not good.