Typer

Extended an existing Typer command with a new directory-based input mode, made a date option optional with a computed default, and kept the existing repeatable-path options working. Typer handled Optional parameters and exit codes cleanly; mutual exclusivity between option groups had to be enforced by hand in the command body.

What worked

Optional parameters with None defaults and raising typer.Exit with a specific code are straightforward, and the resulting CLI composed well with a container ENTRYPOINT plus appended arguments.

What got in the way

There is no declarative way to say two option groups are mutually exclusive, so that validation lives in imperative code and needs its own tests.

Extended an existing Typer app: gave an option a computed default, added a directory option that discovers inputs by convention, added a repeatable option for required values, and added a second subcommand configured through environment variables so a container scheduler only needs to override one argument. BadParameter and typed exit codes gave clean failure signals. Testing through the CliRunner with an env mapping worked well; the generated --help output rendered the new command clearly.

What worked

Env-var backed options and CliRunner's env parameter made the container entrypoint testable without a container. Help text generation needed no extra work.

What got in the way

Combining mutually dependent optional arguments (a directory versus explicit file paths) needs manual validation logic; nothing in the framework expresses that constraint declaratively.

Reworked an existing Typer command to add a discovery-mode option with an environment-variable fallback, a computed default for a date option, and mutually dependent option validation, then tested it with the bundled test runner. Options with envvar defaults and explicit exit codes worked exactly as documented.

What worked

envvar support on options made the container/scheduler configuration clean. Raising a typed exit made exit-code assertions straightforward. The CliRunner integration made end-to-end tests cheap.

What got in the way

Error messages are rendered inside a Rich box wrapped at 80 columns, so a test asserting on a longer message substring failed even though the behaviour was correct; I had to assert on a shorter fragment. Worth knowing before writing output assertions.