Standalone tempest/console fails obscurely on required-argument validation when tempest/event-bus is missing

[marccoup]

Tempest version

3.0

PHP version

8.5

Operating system

macOS

Description

When building a standalone console app with only tempest/console (as documented in the console package docs), commands with required parameters can fail in a non-obvious way during normal interactive use.

If a required argument is omitted, Tempest correctly prompts for it. The failure happens when the user submits invalid input (e.g. pressing Enter on an empty value). Tempest then tries to render a validation error message and throws:

× // Tempest\Validation\Exceptions\TranslatorWasRequired
× // A translator instance is required to generate validation error messages, but none was provided.

This is surprising because:

• Required parameters are extremely common: most real commands have at least one required argument, so you can hit this almost immediately after setting up (this is what happened to me!)
• The standalone setup docs do not mention this dependency: following them alone is enough to hit the failure.
• The failure is obscured: the prompt appears and looks fine; the crash only happens on validation failure, and the exception points at Validator / translation, not at a missing package or incomplete setup.
• The root cause is indirect: tempest/console pulls in tempest/validation which in turn pulls in tempest/intl, but TranslatorInitializer resolves EventBus, and tempest/event-bus is not installed by a minimal standalone setup. Validator accepts an optional ?Translator and silently gets null when translation cannot be constructed, so the app boots until validation needs a message.

Steps to reproduce

1. Create a minimal standalone console app as documented in the console package docs
2. Define a simple command with a required argument:

#[ConsoleCommand(name: 'foo')]
public function __invoke(string $bar): ExitCode {
    return ExitCode::SUCCESS;
}

3. Run without the argument in an interactive TTY:

./my-cli example:run

4. At the prompt, press Enter without typing a value.

Expected behaviour

Either:

1. Validation fails with a clear, user-facing message (e.g. “must not be empty”), or
2. Setup fails early with documentation or an error that makes the missing dependency obvious.

Actual behaviour

TranslatorWasRequired is thrown from Validator::getErrorMessage().

Environment

• PHP 8.5
• tempest/console ^3.13
• Minimal install: tempest/console only (no tempest/event-bus)

Why (I think) this matters

Required arguments are a super common pattern for CLI commands. A developer following the standalone console docs, defining a normal command, and testing it interactively can easily hit this without any indication that tempest/event-bus is needed. The error reads like an internal framework bug rather than a setup gap.

Suggested directions

I see two reasonable fixes; happy to open a PR for whichever you as maintainers prefer:

Option 1 - Documentation

Update the standalone console docs to note that interactive prompts with validation (including automatic prompting for missing required arguments) need a working Translator, which currently requires installing tempest/event-bus, the whole fix just being to run:

composer require tempest/event-bus

Document the symptom (TranslatorWasRequired) so users can connect it to the missing dependency.

Option 2 - Package dependency

Add tempest/event-bus as a direct requirement of tempest/console so standalone console apps work out of the box for the common case of required parameters and interactive validation, without an extra install step.

Option 1 is the smallest change; Option 2 gives the better DX for the most common standalone use case. I think that either would be a big improvement over the current behaviour.