Golang Google Wire

1. Never edit wire_gen.go — it is overwritten on every wire ./... run. Treat it as a build artifact that happens to be committed; source of truth is the provider and injector files. 2. Always add //go:build wireinject to injector files — omitting it causes duplicate-symbol compile errors because both the stub and the generated file define the same function. 3. Use named types to distinguish values of the same underlying type — wire enforces one provider per type; named types like type DSN string let you have PrimaryDSN and ReplicaDSN coexist. 4. Keep library provider sets minimal and backward-compatible — adding new required inputs breaks downstream injectors; removing outputs does too. Introduce only newly-created types in the same release. 5. Return (T, func(), error) from cleanup providers and let wire chain them — wire generates the correct reverse-order cleanup and handles partial failures (if construction fails midway, only already-built cleanups run). 6. Keep injector files focused — one function per file, one package import at a time. Fat injectors with dozens of wire.Build arguments are hard to reason about; delegate to per-package sets.