fix: stagger starter migrations (#8216)

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#### Summary

Fixes #<replace_with_issue_number>

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Co-authored-by: Katherine Beck <katherine.beck@netlify.com>

Author: kathmbeck

src/commands/database/db-init.ts

@@ -175,13 +175,13 @@ const scaffoldStarter = async (
       cwd: projectRoot,
     })
 
-    // The seed's timestamp is generated AFTER drizzle-kit runs, so it
-    // lexicographically sorts after whatever drizzle-kit produced. If they
-    // happen to land in the same second, `create_planets` < `seed_planets`
-    // alphabetically still runs the CREATE TABLE first. We use the same
-    // directory layout drizzle-kit uses so both migrations look consistent
-    // in the migrations/ folder.
-    const seedDirName = `${generateNextPrefix([], 'timestamp')}_${SEED_MIGRATION_NAME}`
+    // The seed's timestamp is generated AFTER drizzle-kit runs. We read the
+    // migrations directory so `generateNextPrefix` can detect a collision and
+    // bump the prefix by one second if the two migrations landed in the same
+    // second — the deploy-time validator rejects duplicate numeric prefixes.
+    const existingMigrations = await readDirectoryEntries(migrationsDirectory)
+    const seedPrefix = generateNextPrefix(existingMigrations, 'timestamp')
+    const seedDirName = `${seedPrefix}_${SEED_MIGRATION_NAME}`
     const seedDir = join(migrationsDirectory, seedDirName)
     await mkdir(seedDir, { recursive: true })
     await writeFile(join(seedDir, 'migration.sql'), DRIZZLE_SEED_SQL, { flag: 'wx' })

src/commands/database/db-migration-new.ts

@@ -47,7 +47,12 @@ export const detectNumberingScheme = (existingNames: string[]): NumberingScheme
 
 export const generateNextPrefix = (existingNames: string[], scheme: NumberingScheme): string => {
   if (scheme === 'timestamp') {
-    return utcTimestampPrefix()
+    const now = utcTimestampPrefix()
+    const existingPrefixes = new Set(existingNames.map((n) => /^(\d+)/.exec(n)?.[1]).filter(Boolean))
+    if (existingPrefixes.has(now)) {
+      return utcTimestampPrefix(new Date(Date.now() + 1000))
+    }
+    return now
   }
 
   const prefixes = existingNames.map((name) => {