Fix nested D1 migration loading in vitest pool

[cyphercodes]

Fixes #14866.

Read D1 migration files recursively so readD1Migrations() supports the nested layout that migrations_pattern can match, such as 0001_init/migration.sql. The returned migration names preserve forward-slash relative paths and are sorted by migration prefix.

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• Tests
  • Tests included/updated
  • Automated tests not possible - manual testing has been completed as follows: N/A
  • Additional testing not necessary because: N/A
• Public documentation
  • Documentation not necessary because: this fixes runtime/test helper behavior without changing public docs

Note

This is a contribution from an AI agent: Hermes Agent, gpt-5.5.

Validation:

• pnpm --filter @cloudflare/vitest-pool-workers test d1.test.ts
• pnpm --filter @cloudflare/vitest-pool-workers check:type
• pnpm --filter @cloudflare/vitest-pool-workers build
• oxfmt --check packages/vitest-pool-workers/src/pool/d1.ts packages/vitest-pool-workers/test/d1.test.ts .changeset/read-nested-d1-migrations.md
• git diff --check

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🦋 Changeset detected

Latest commit: f50d753

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@cloudflare/vitest-pool-workers	Patch

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[workers-devprod]

Codeowners approval required for this PR:

• @cloudflare/wrangler

Show detailed file reviewers

• .changeset/read-nested-d1-migrations.md: [@cloudflare/wrangler]
• packages/vitest-pool-workers/src/pool/d1.ts: [@cloudflare/wrangler]
• packages/vitest-pool-workers/test/d1.test.ts: [@cloudflare/wrangler]

[devin-ai-integration]

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[edmundhung]

Thanks for working on this, @cyphercodes. The nested migration case definitely needs fixing.

I think the current recursive scan could be confusing as it may not match migrations_pattern exactly and could include SQL files that Wrangler would otherwise ignore.

How about supporting an explicit options form?

// Keep the current API signature for backward compatibility
readD1Migrations(migrationsDir: string);
// New: Accept an option that allow you to specify how it should discover the migrations files similar to the config
readD1Migrations({
  projectPath, // Optional: defaults to process.cwd()
  migrationsDir,
  migrationsPattern,
});

It would also be great if you could extract the existing discovery logic into @cloudflare/workers-utils so it could be reused by both Wrangler and Vitest Pool Workers:

type D1MigrationFile = {
  name: string;
  filePath: string;
};

function getD1MigrationFiles(
  options: {
    projectPath: string;
    migrationsDir?: string;
    migrationsPattern?: string;
  }
): D1MigrationFile[];

Would you be open to implementing it along those lines? It's a slightly broader change, but it would help us keeping both code paths consistent and make this easier to maintain long term.