[BUG] Cloudflare deployer fails when PostgresStore is not used due to unnecessary Babel plugin execution

[Naokiakazawa]

Describe the Bug

The Cloudflare deployer applies the postgres-store-instance-checker Babel plugin unconditionally, even when PostgresStore is not being used in the application. This causes build failures with the error:

ERROR: postgres-store-instance-checker plugin did not return code, there is likely a bug in the plugin.

Root Cause:
The postgres-store-instance-checker plugin is always included in the bundler options regardless of whether @mastra/pg is actually used as a dependency:

// Current problematic implementation
inputOptions.plugins = [
  virtual({ ... }),
  ...inputOptions.plugins,
  postgresStoreInstanceChecker(), // ← Always applied
  mastraInstanceWrapper(mastraEntryFile),
];

Impact:

• Applications using other storage solutions (Redis, Memory, D1, etc.) fail to build
• Applications with no storage at all fail to build
• Unnecessary Babel transformations are performed even when not needed

Steps To Reproduce

1. Create a Mastra app using Redis or Memory storage (no @mastra/pg dependency)
2. Configure Cloudflare deployer
3. Run build command
4. Observe the plugin error

Expected Behavior

The postgres-store-instance-checker plugin should only be applied when:

1. @mastra/pg package is actually installed as a dependency
2. PostgresStore is being used in the application

Proposed Solution:

// Check if PostgresStore is being used before applying the plugin
const hasPostgresStore = (await this.deps.checkDependencies(['@mastra/pg'])) === `ok`;
if (hasPostgresStore) {
  plugins.push(postgresStoreInstanceChecker());
}

This would ensure:

• ✅ PostgresStore users get proper instance validation
• ✅ Non-PostgresStore users can build without errors
• ✅ Better performance by skipping unnecessary transformations

Environment Information

• @mastra/deployer-cloudflare　0.13.8-alpha.0
• mastra 0.16.3
• Nodejs v22.15.0
• OS MacOS 15.6.1

Verification

• I have searched the existing issues to make sure this is not a duplicate
• I have included sufficient information for the team to reproduce and understand the issue

[rhaenni]

same issue, thanks for your proposed solution, used pnpm patch to implement the workaround