fix: validate player positions in lineup before game start

Prevents PositionNotFoundException from crashing mlb-campaign when a
player is placed at a position they cannot play (e.g. an outfielder
listed at Catcher in the Google Sheet). Adds early validation in
get_lineups_from_sheets and proper error handling at all read_lineup
call sites so the user gets a clear message and the game is cleaned up.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

cogs/gameplay.py

@@ -436,19 +436,26 @@ class Gameplay(commands.Cog):
             await interaction.channel.send(content=f'### {human_team.lname} Starting Pitcher', view=sp_view)
             
             try:
-                await asyncio.sleep(5)   
+                await asyncio.sleep(5)
                 this_play = await read_lineup(
-                    session, 
-                    interaction, 
+                    session,
+                    interaction,
                     this_game=this_game,
                     lineup_team=human_team,
                     sheets_auth=self.sheets,
                     lineup_num=1 if roster_choice == 'vs Right' else 2,
                     league_name=this_game.game_type
                 )
+            except PositionNotFoundException as e:
+                logger.error(f'Position validation failed during lineup load: {e}')
+                this_game.active = False
+                session.add(this_game)
+                session.commit()
+                await interaction.channel.send(content=str(e))
+                return
             except LineupsMissingException as e:
                 logger.error(f'Attempting to start game, pausing for 5 seconds: {e}')
-                await asyncio.sleep(5)            
+                await asyncio.sleep(5)
             
             try:
                 this_play = this_game.current_play_or_none(session)
@@ -668,6 +675,13 @@ class Gameplay(commands.Cog):
                     lineup_num=1 if roster_choice == 'vs Right' else 2,
                     league_name=this_game.game_type
                 )
+            except PositionNotFoundException as e:
+                logger.error(f'Position validation failed during lineup load: {e}')
+                this_game.active = False
+                session.add(this_game)
+                session.commit()
+                await interaction.channel.send(content=str(e))
+                return
             except LineupsMissingException as e:
                 # Expected - can't initialize play without SP yet
                 logger.info(f'Field player lineup read from sheets, waiting for SP selection: {e}')
@@ -1044,14 +1058,18 @@ class Gameplay(commands.Cog):
             logger.info(f'lineup: {lineup} / value: {lineup.value} / name: {lineup.name}')
             try:
                 this_play = await read_lineup(
-                    session, 
-                    interaction, 
+                    session,
+                    interaction,
                     this_game=this_game,
                     lineup_team=this_team,
                     sheets_auth=self.sheets,
                     lineup_num=int(lineup.value),
                     league_name=this_game.game_type
                 )
+            except PositionNotFoundException as e:
+                logger.error(f'Position validation failed during lineup load: {e}')
+                await interaction.edit_original_response(content=str(e))
+                return
             except LineupsMissingException as e:
                 await interaction.edit_original_response(content='Run `/set starting-pitcher` to select your SP')
                 return

command_logic/logic_gameplay.py

@@ -628,7 +628,13 @@ async def read_lineup(
 
     for batter in human_lineups:
         if batter.position != "DH":
-            await get_position(session, batter.card, batter.position)
+            try:
+                await get_position(session, batter.card, batter.position)
+            except PositionNotFoundException:
+                raise PositionNotFoundException(
+                    f"Could not find {batter.position} ratings for **{batter.player.name_with_desc}**. "
+                    f"Please check your lineup in Google Sheets and make sure each player is at a valid position."
+                )
 
     return this_game.initialize_play(session)
 
@@ -1096,6 +1102,19 @@ async def get_lineups_from_sheets(
             raise SyntaxError(
                 f"Easy there, champ. Looks like card ID {row[1]} belongs to the {this_card.team.lname}. Try again with only cards you own."
             )
+
+        position = row[0].upper()
+        if position != "DH":
+            player_positions = [
+                getattr(this_card.player, f"pos_{i}") for i in range(1, 9)
+                if getattr(this_card.player, f"pos_{i}") is not None
+            ]
+            if position not in player_positions:
+                raise PositionNotFoundException(
+                    f"**{this_card.player.name_with_desc}** (card {this_card.id}) is listed at **{position}** in your lineup, "
+                    f"but can only play {', '.join(player_positions)}. Please fix your lineup in Google Sheets."
+                )
+
         card_id = row[1]
         card_ids.append(str(card_id))