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PandeyandGitHub 08b249183f refactor(foundryctl): silent-by-default logs, typed exit codes, ban fmt.Errorf (#118)
## Summary

Reshape foundryctl's output contract so it composes with agents and
shell pipelines. Three changes that fall out of the same observation:
**stdout, stderr, and exit codes should be a stable contract — today
they're conflated.**

- **Logger to stderr, silent by default.** `instrumentation.NewLogger`
writes to `os.Stderr` (was `os.Stdout`) and uses `slog.DiscardHandler`
unless `--debug` is set. Matches helm/aws CLI convention. stdout is now
reserved for command results.
- **Typed exit codes.** `internal/errors.typ` carries a `code int`
field; `errors.ExitCode(err)` walks the wrap chain via `errors.As` and
returns a deterministic code: `InvalidInput=2, NotFound=3,
Unsupported=4, Internal=5, Fatal=6`, untyped=1, nil=0. Compact 1-6
scheme rather than sysexits.h because sysexits would collapse `Internal`
and `Fatal` into the same `EX_SOFTWARE (70)`, losing a distinction we
care about (Fatal = recovered panic; Internal = expected-but-failed
path). `cmd/foundryctl/main.go` now exits with `errors.ExitCode(err)`.
- **`fmt.Errorf` forbidden by lint.** New forbidigo rules in
`.golangci.yml` ban `fmt.Errorf` and `fmt.Print*` / `print` / `println`.
168 call sites across 38 files converted to `errors.Newf` /
`errors.Wrapf` with contextually-chosen types. Narrow exception for
`internal/errors/error_test.go` so the ExitCode wrap-chain test stays
authentic.

Sites of note for review:
- `internal/errors/type.go` — exit code mapping table (one source of
truth)
- `internal/errors/error.go` — `ExitCode(err)` helper
- `internal/instrumentation/logger.go` — `slog.DiscardHandler` default
- `.golangci.yml` — forbidigo config + the single narrow test exclusion

## Test plan

- [x] `go build ./...`
- [x] `go test ./...` (all packages pass; new `TestExitCode` covers 9
cases: nil, untyped, each typed, fmt.Errorf-wrapped,
foundry-Wrapf-wrapped)
- [x] `golangci-lint run ./...` — 0 issues
- [x] Manual: `foundryctl forge` on a missing file exits non-zero and
emits nothing on stdout (logs hidden); `--debug` emits JSON on stderr
only
- [x] Manual: end-to-end forge + cast against the docker/compose flavor
still produces a healthy stack
2026-05-17 23:01:00 +05:30

22 lines
516 B
Go

package writer
import (
"encoding/json"
"io"
)
// WriteOutput writes m's MarshalJSON bytes (with a trailing newline) to w.
// Used for stream payloads that don't have a filesystem path. Each implementer
// owns its own envelope (e.g. errors.Envelope wraps as {"exception": {...}})
// via MarshalJSON, so the writer stays a thin transport.
func WriteOutput(w io.Writer, m json.Marshaler) error {
data, err := m.MarshalJSON()
if err != nil {
return err
}
_, err = w.Write(append(data, '\n'))
return err
}