Fix broken drizzle migration chain and add prevention guidelines

The migration system was broken due to three issues:
1. Snapshot 0067 had an invalid `autoincrement` field (PostgreSQL doesn't
   support this) causing Zod validation to fail with "data is malformed"
2. Migrations 0068 and 0069 were missing snapshot files, breaking the
   snapshot chain required by `drizzle-kit generate`
3. Orphaned file 0048_mean_enchantress.sql existed outside the journal

Fixed by removing the invalid field, regenerating migrations 0068-0069
with proper snapshots via `drizzle-kit generate`, deleting the orphaned
file, and adding a no-op verification migration (0070). Made migration
0069 idempotent with IF EXISTS/IF NOT EXISTS guards for production safety.

Updated CLAUDE.md with rules to prevent manual migration/journal editing
and ensure snapshots are always generated.

https://claude.ai/code/session_01JuVHpRPa974MKSHoXNGkgU

CLAUDE.md

@@ -205,9 +205,20 @@ Do not consider a feature complete until tests are written and passing.
 
 1. Update `database/schema.ts` with new tables/columns
 2. Run `npm run db:generate` to create migration
-3. Run `npm run db:migrate` to apply migration
-4. Add model functions in `app/models/` for new queries
-5. Update TypeScript types if needed
+3. **Verify** the generated migration SQL in `drizzle/` is correct
+4. **Verify** a corresponding snapshot was created in `drizzle/meta/` (e.g., `0070_snapshot.json`)
+5. Run `npm run db:migrate` to apply migration
+6. Add model functions in `app/models/` for new queries
+7. Update TypeScript types if needed
+
+**Drizzle Migration Rules (CRITICAL):**
+- **NEVER** manually create migration SQL files or journal entries. Always use `drizzle-kit generate` or `drizzle-kit generate --custom` so that snapshot files are created automatically.
+- **NEVER** edit `drizzle/meta/_journal.json` by hand. The journal and snapshots must stay in sync — drizzle-kit manages both.
+- Every migration **must** have a matching snapshot in `drizzle/meta/`. Missing snapshots cause `drizzle-kit generate` to fail with "data is malformed" errors, which blocks all future migration generation.
+- Snapshot JSON must only contain PostgreSQL-valid fields. Do not add `"autoincrement"` to column definitions — PostgreSQL uses sequences/serial instead, and invalid fields cause Zod validation failures.
+- If `drizzle-kit generate` prompts for column renames interactively, use `drizzle-kit generate --custom` instead and write the migration SQL by hand (include data backfill logic as needed).
+- After generating, run `drizzle-kit generate` again to confirm "No schema changes" — this validates the snapshot chain is healthy.
+- For destructive migrations (dropping columns, renaming), make the SQL idempotent with `IF EXISTS`/`IF NOT EXISTS` guards where possible.
 
 ### Adding Socket.IO Events
 

drizzle/0048_mean_enchantress.sql

@@ -1,19 +0,0 @@
-DO $$ BEGIN
-  IF NOT EXISTS (SELECT 1 FROM pg_enum WHERE enumlabel = 'ncaam_bracket' AND enumtypid = (SELECT oid FROM pg_type WHERE typname = 'simulator_type')) THEN
-    ALTER TYPE "public"."simulator_type" ADD VALUE 'ncaam_bracket';
-  END IF;
-END $$;
---> statement-breakpoint
-DO $$ BEGIN
-  IF NOT EXISTS (SELECT 1 FROM pg_enum WHERE enumlabel = 'ncaaw_bracket' AND enumtypid = (SELECT oid FROM pg_type WHERE typname = 'simulator_type')) THEN
-    ALTER TYPE "public"."simulator_type" ADD VALUE 'ncaaw_bracket';
-  END IF;
-END $$;
---> statement-breakpoint
-DO $$ BEGIN
-  IF NOT EXISTS (SELECT 1 FROM pg_enum WHERE enumlabel = 'nba_bracket' AND enumtypid = (SELECT oid FROM pg_type WHERE typname = 'simulator_type')) THEN
-    ALTER TYPE "public"."simulator_type" ADD VALUE 'nba_bracket';
-  END IF;
-END $$;
---> statement-breakpoint
-ALTER TABLE "leagues" ADD COLUMN IF NOT EXISTS "discord_webhook_url" varchar(500);

drizzle/0069_draft_window.sql

@@ -1,19 +1,18 @@
--- Step 1: Add new columns as nullable
-ALTER TABLE "sports_seasons" ADD COLUMN "draft_on" date;--> statement-breakpoint
-ALTER TABLE "sports_seasons" ADD COLUMN "draft_off" date;--> statement-breakpoint
+-- Step 1: Add new columns as nullable (IF NOT EXISTS for idempotency)
+ALTER TABLE "sports_seasons" ADD COLUMN IF NOT EXISTS "draft_on" date;--> statement-breakpoint
+ALTER TABLE "sports_seasons" ADD COLUMN IF NOT EXISTS "draft_off" date;--> statement-breakpoint
 
--- Step 2: Backfill data based on existing is_draftable flag
-UPDATE "sports_seasons"
-SET "draft_on" = '2026-04-06', "draft_off" = '2099-12-31'
-WHERE "is_draftable" = true;--> statement-breakpoint
-
-UPDATE "sports_seasons"
-SET "draft_on" = '2020-01-01', "draft_off" = '2020-12-31'
-WHERE "is_draftable" = false;--> statement-breakpoint
+-- Step 2: Backfill data based on existing is_draftable flag (only if column still exists)
+DO $$ BEGIN
+  IF EXISTS (SELECT 1 FROM information_schema.columns WHERE table_name = 'sports_seasons' AND column_name = 'is_draftable') THEN
+    UPDATE "sports_seasons" SET "draft_on" = '2026-04-06', "draft_off" = '2099-12-31' WHERE "is_draftable" = true;
+    UPDATE "sports_seasons" SET "draft_on" = '2020-01-01', "draft_off" = '2020-12-31' WHERE "is_draftable" = false;
+  END IF;
+END $$;--> statement-breakpoint
 
 -- Step 3: Apply NOT NULL constraints
 ALTER TABLE "sports_seasons" ALTER COLUMN "draft_on" SET NOT NULL;--> statement-breakpoint
 ALTER TABLE "sports_seasons" ALTER COLUMN "draft_off" SET NOT NULL;--> statement-breakpoint
 
--- Step 4: Drop old column
-ALTER TABLE "sports_seasons" DROP COLUMN "is_draftable";
+-- Step 4: Drop old column (IF EXISTS for idempotency)
+ALTER TABLE "sports_seasons" DROP COLUMN IF EXISTS "is_draftable";

drizzle/0070_verify_migrations.sql

@@ -0,0 +1,3 @@
+-- Verification migration: confirms drizzle migration chain is healthy.
+-- This is a no-op migration that validates the migration system works end-to-end.
+SELECT 1;

drizzle/meta/0067_snapshot.json

@@ -1159,8 +1159,7 @@
           "name": "world_ranking",
           "type": "integer",
           "primaryKey": false,
-          "notNull": false,
-          "autoincrement": false
+          "notNull": false
         }
       },
       "indexes": {

drizzle/meta/_journal.json

@@ -481,16 +481,23 @@
     {
       "idx": 68,
       "version": "7",
-      "when": 1775000000000,
-      "tag": "0068_cs2_major_simulator",
+      "when": 1775485575205,
+      "tag": "0068_soft_silk_fever",
       "breakpoints": true
     },
     {
       "idx": 69,
       "version": "7",
-      "when": 1744012800000,
+      "when": 1775485599229,
       "tag": "0069_draft_window",
       "breakpoints": true
+    },
+    {
+      "idx": 70,
+      "version": "7",
+      "when": 1775485630297,
+      "tag": "0070_verify_migrations",
+      "breakpoints": true
     }
   ]
 }