Severity: Error | Category: Linting

Description

Detects when the same key is defined multiple times in a single .env file.

Why It's an Error

Duplicate keys create ambiguity:

1. Which value should the application use?
2. Different parsers may choose first or last occurrence
3. Can lead to unexpected behavior in production

Examples

❌ Problematic

DATABASE_URL=postgres://localhost:5432/db
DATABASE_URL=postgres://prod-server:5432/db

✅ Fixed

DATABASE_URL=postgres://prod-server:5432/db

Detection

$ envcheck lint .env

.env:5: E001: Duplicate key: DATABASE_URL (first defined at line 3)

Auto-Fix

The fix command cannot automatically resolve duplicate keys (requires manual decision).

$ envcheck fix .env

⚠ E001: Duplicate keys must be resolved manually:
   - DATABASE_URL at lines 3, 5

Configuration

# .envcheckrc.yaml
rules:
  E001:
    severity: error  # Can downgrade to warning if needed
    auto_fix: false  # Always false for this rule

See Also

• E002: Invalid Syntax