Replace the existing two-query create_or_update implementation with a
single atomic PostgreSQL upsert using ON CONFLICT clause to eliminate
race conditions and improve performance.
Race condition fix:
The previous implementation had a critical race condition where
multiple concurrent requests could:
1. Both call find() and get None (record doesn't exist)
2. Both call create() and the second one fails with duplicate key
error
3. Or between find() and create(), another transaction inserts the
record
This created unreliable behavior in high-concurrency scenarios.
Changes:
- Add generate_upsert_query function in trait_implementation.rs
- Generate SQL with INSERT ... ON CONFLICT ... DO UPDATE SET pattern
- Remove default trait implementation that used separate
find/create/update calls
- Update derive_trait to include upsert query generation
- Convert create_or_update from default implementation to required
trait method
The new implementation eliminates race conditions while reducing
database round trips from 2-3 queries down to 1, significantly
improving both reliability and performance.
Replace Nix flake-based development setup with devenv for better
developer experience and more streamlined environment management.
Changes:
- Remove flake.nix and flake.lock files
- Add devenv.nix, devenv.yaml, and devenv.lock configuration
- Update .envrc to use devenv instead of nix develop
- Remove Docker development setup (compose.dev.yml, docker/mod.just)
- Expand .gitignore with comprehensive IDE and OS exclusions
- Remove Docker-related just commands from justfile
Replaces the existing README with a comprehensive guide that
significantly improves the developer and user experience. The new README
provides complete documentation for all Georm features and a detailed
development setup guide.
