Gerbview: fix broken behavior for deprecated command IPPOS and IPNEG

Fixes https://gitlab.com/kicad/code/kicad/-/issues/21715

(cherry picked from commit 45166bf5c3477f229d6011506508aa22e4bc0f61)

common/libeval_compiler/libeval_compiler.cpp

@@ -1150,7 +1150,9 @@ void UOP::Exec( CONTEXT* ctx )
         return;
 
     case TR_OP_METHOD_CALL:
-        m_func( ctx, m_ref.get() );
+        if( m_func )
+            m_func( ctx, m_ref.get() );
+
         return;
 
     default:
@@ -1283,9 +1285,8 @@ VALUE* UCODE::Run( CONTEXT* ctx )
     }
     catch(...)
     {
-        // rules which fail outright should not be fired
-        std::unique_ptr<VALUE> temp_false = std::make_unique<VALUE>( 0 );
-        return ctx->StoreValue( temp_false.get() );
+        // rules which fail outright should not be fired; return 0/false
+        return ctx->StoreValue( new VALUE( 0 ) );
     }
 
     if( ctx->SP() == 1 )
@@ -1301,8 +1302,7 @@ VALUE* UCODE::Run( CONTEXT* ctx )
         wxASSERT( ctx->SP() == 1 );
 
         // non-well-formed rules should not be fired on a release build
-        std::unique_ptr<VALUE> temp_false = std::make_unique<VALUE>( 0 );
-        return ctx->StoreValue( temp_false.get() );
+        return ctx->StoreValue( new VALUE( 0 ) );
     }
 }
 

gerbview/rs274x.cpp

@@ -671,8 +671,7 @@ bool GERBER_FILE_IMAGE::ExecuteRS274XCommand( int aCommand, char* aBuff,
         break;
 
     case IMAGE_POLARITY:
-        // These commands are deprecated since 2012.
-        // So do nothing and prompt the user about this command
+        // Note: these commands IPPOS and IPNEG are deprecated since 2012.
         if( strncasecmp( aText, "NEG", 3 ) == 0 )
         {
             m_ImageNegative = true;
@@ -688,7 +687,6 @@ bool GERBER_FILE_IMAGE::ExecuteRS274XCommand( int aCommand, char* aBuff,
             // actual effect. Just skip it.
         }
 
-        ok = false;
         break;
 
     case LOAD_POLARITY: