fix(env): schema treatment of empty string for redis url

[icecrasher321]

Summary

Docker compose injects as empty string which leads to failures if redis not setup.

Type of Change

• Bug fix

Testing

N/A

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

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1 Skipped Deployment

Project	Deployment	Actions	Updated (UTC)
docs	Skipped		Jun 3, 2026 5:15pm

[cursor]

PR Summary

Low Risk
Small env parsing tweak with no auth or data-path changes; only affects whether Redis adapter is enabled when the variable is empty.

Overview
Treats a blank REDIS_URL (e.g. from Docker Compose when Redis is not configured) as unset before Zod validation, so startup no longer fails URL parsing and the realtime service can run in single-pod mode without Redis.

The change is a z.preprocess on REDIS_URL in apps/realtime/src/env.ts that maps whitespace-only strings to undefined, then applies the existing optional URL schema.

^{Reviewed by Cursor Bugbot for commit 348ab13. Configure here.}

[greptile-apps]

Greptile Summary

This PR fixes a validation failure in the realtime app's env schema when Docker Compose injects REDIS_URL as an empty string (its default for unset variables) rather than leaving it absent.

• REDIS_URL is now wrapped in z.preprocess() to convert empty or whitespace-only strings to undefined before Zod's URL validator runs, preventing a startup crash when Redis is not configured.
• No other optional URL fields in apps/realtime/src/env.ts require the same treatment (all others are either required or validated as plain strings, not URLs).

Confidence Score: 5/5

Safe to merge — the change is a targeted one-line schema fix with no side effects on other env fields.

The fix is minimal and correct: z.preprocess converts empty/whitespace strings to undefined before the URL validator runs, which is the standard Zod idiom for this pattern. The typeof value === 'string' guard prevents unexpected coercion of non-string inputs. No other fields in this schema are affected.

No files require special attention.

Important Files Changed

Filename	Overview
apps/realtime/src/env.ts	Wraps REDIS_URL in z.preprocess to coerce empty strings to undefined, fixing Docker Compose startup failures when Redis is not configured.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[process.env.REDIS_URL] --> B{preprocess}
    B -->|empty or whitespace string| C[undefined]
    B -->|non-empty string| D[original value]
    C --> E{url validator - optional}
    D --> E
    E -->|undefined| F[Valid - Redis disabled]
    E -->|valid URL| G[Valid - Redis enabled]
    E -->|invalid URL| H[Validation error thrown]

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