fix: prevent partial DB writes and show detailed errors on scorecard submission failure

Read all spreadsheet data (plays, box score, pitching decisions) before any
database writes so formula errors like #N/A don't leave the DB in a partial
state. Also preserve SheetsException detail through the error chain and show
users the specific cell/error instead of a generic failure message.

Closes #78

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

commands/league/submit_scorecard.py

@@ -210,17 +210,41 @@ class SubmitScorecardCommands(commands.Cog):
 
             game_id = scheduled_game.id
 
-            # Phase 6: Read Scorecard Data
+            # Phase 6: Read ALL Scorecard Data (before any DB writes)
+            # Reading everything first prevents partial commits if the
+            # spreadsheet has formula errors (e.g. #N/A in pitching decisions)
             await interaction.edit_original_response(
-                content="📊 Reading play-by-play data..."
+                content="📊 Reading scorecard data..."
             )
 
             plays_data = await self.sheets_service.read_playtable_data(scorecard)
+            box_score = await self.sheets_service.read_box_score(scorecard)
+            decisions_data = await self.sheets_service.read_pitching_decisions(
+                scorecard
+            )
 
             # Add game_id to each play
             for play in plays_data:
                 play["game_id"] = game_id
 
+            # Add game metadata to each decision
+            for decision in decisions_data:
+                decision["game_id"] = game_id
+                decision["season"] = current.season
+                decision["week"] = setup_data["week"]
+                decision["game_num"] = setup_data["game_num"]
+
+            # Validate WP and LP exist and fetch Player objects
+            wp, lp, sv, holders, _blown_saves = (
+                await decision_service.find_winning_losing_pitchers(decisions_data)
+            )
+
+            if wp is None or lp is None:
+                await interaction.edit_original_response(
+                    content="❌ Your card is missing either a Winning Pitcher or Losing Pitcher"
+                )
+                return
+
             # Phase 7: POST Plays
             await interaction.edit_original_response(
                 content="💾 Submitting plays to database..."
@@ -244,10 +268,7 @@ class SubmitScorecardCommands(commands.Cog):
                 )
                 return
 
-            # Phase 8: Read Box Score
-            box_score = await self.sheets_service.read_box_score(scorecard)
-
-            # Phase 9: PATCH Game
+            # Phase 8: PATCH Game
             await interaction.edit_original_response(
                 content="⚾ Updating game result..."
             )
@@ -275,33 +296,7 @@ class SubmitScorecardCommands(commands.Cog):
                 )
                 return
 
-            # Phase 10: Read Pitching Decisions
-            decisions_data = await self.sheets_service.read_pitching_decisions(
-                scorecard
-            )
-
-            # Add game metadata to each decision
-            for decision in decisions_data:
-                decision["game_id"] = game_id
-                decision["season"] = current.season
-                decision["week"] = setup_data["week"]
-                decision["game_num"] = setup_data["game_num"]
-
-            # Validate WP and LP exist and fetch Player objects
-            wp, lp, sv, holders, _blown_saves = (
-                await decision_service.find_winning_losing_pitchers(decisions_data)
-            )
-
-            if wp is None or lp is None:
-                # Rollback
-                await game_service.wipe_game_data(game_id)
-                await play_service.delete_plays_for_game(game_id)
-                await interaction.edit_original_response(
-                    content="❌ Your card is missing either a Winning Pitcher or Losing Pitcher"
-                )
-                return
-
-            # Phase 11: POST Decisions
+            # Phase 9: POST Decisions
             await interaction.edit_original_response(
                 content="🎯 Submitting pitching decisions..."
             )
@@ -361,6 +356,30 @@ class SubmitScorecardCommands(commands.Cog):
             # Success!
             await interaction.edit_original_response(content="✅ You are all set!")
 
+        except SheetsException as e:
+            # Spreadsheet reading error - show the detailed message to the user
+            self.logger.error(
+                f"Spreadsheet error in scorecard submission: {e}", error=e
+            )
+
+            if rollback_state and game_id:
+                try:
+                    if rollback_state == "GAME_PATCHED":
+                        await game_service.wipe_game_data(game_id)
+                        await play_service.delete_plays_for_game(game_id)
+                    elif rollback_state == "PLAYS_POSTED":
+                        await play_service.delete_plays_for_game(game_id)
+                except Exception:
+                    pass  # Best effort rollback
+
+            await interaction.edit_original_response(
+                content=(
+                    f"❌ There's a problem with your scorecard:\n\n"
+                    f"{str(e)}\n\n"
+                    f"Please fix the issue in your spreadsheet and resubmit."
+                )
+            )
+
         except Exception as e:
             # Unexpected error - attempt rollback
             self.logger.error(f"Unexpected error in scorecard submission: {e}", error=e)

services/sheets_service.py

@@ -416,6 +416,8 @@ class SheetsService:
             self.logger.info(f"Read {len(pit_data)} valid pitching decisions")
             return pit_data
 
+        except SheetsException:
+            raise
         except Exception as e:
             self.logger.error(f"Failed to read pitching decisions: {e}")
             raise SheetsException("Unable to read pitching decisions") from e
@@ -458,6 +460,8 @@ class SheetsService:
                 "home": [int(x) for x in score_table[1]],  # [R, H, E]
             }
 
+        except SheetsException:
+            raise
         except Exception as e:
             self.logger.error(f"Failed to read box score: {e}")
             raise SheetsException("Unable to read box score") from e