refactor(logging): delete the init logger

[Joibel]

Part 3 of 3: with #16702 and #16703 having moved every config read into constructors, nothing needs to log before main anymore — so the init logger can be deleted outright.

Motivation

The init logger has been a source of subtle process-global behavior: #15863 / #16693 (its signal handler made the v4 controller and server ignore SIGTERM entirely), hidden os.Exit control flow inside a logging package, and buffered messages whose replay depended on construction order. With no remaining producers, deleting it removes the whole class.

Modifications

• New cmdutil.FatalBootstrap(logFormat, err, msg) for the one thing the init logger still did in production: reporting "failed to construct the logger" and exiting. It honors the requested log format when parseable (an improvement — the old path hardcoded JSON) and falls back to JSON when the format flag itself is the invalid input.
• All eight fatal-bootstrap call sites across workflow-controller, argo, and argoexec converted to it; the previously implicit exits (one site had no explicit exit and relied on the init logger's hidden one) are now uniform and explicit.
• E2E fixtures and three argoexec command test files switch from InitLogger contexts to the standard test-logger helpers (logging.TestContext / logging.NewTestLogger).
• util/logging/init.go and init_test.go deleted; NewSlogLoggerCustom no longer replays init logs. GetExitFunc/SetExitFunc remain (still used by the slog fatal path, argo lint, and FatalBootstrap). Removed exported API: logging.InitLogger, logging.InitLoggerInContext.

Verification

go build ./..., golangci-lint (0 issues), go test ./util/... ./cmd/... -count=1 pass (one pre-existing, unrelated TestEmissary/Sub-process environment failure reproduces identically on the parent commit). Functional checks: workflow-controller --loglevel bogus prints one text-format error line (honoring the default --log-format text) and exits 1; with --log-format json the line is JSON. A repo-wide grep confirms zero references to InitLogger/initLog/emitInitLogs outside vendor.

Documentation

Not needed: no user-facing interface changes; bootstrap failure output now matches the documented --log-format flag instead of ignoring it.

AI

Claude Code planned and implemented this change under human direction, with per-task and whole-branch review passes; the author reviewed and takes responsibility for the result.

🤖 Generated with Claude Code

https://claude.ai/code/session_01SqVAUnuPJZ7sQZCy44bBSE