Q: Is there a way to fail if unknown flags/arguments are passed?

Hi,

If the user passes an undefined flag is there a way to fail the cli/dispatch?

I assume that is a design choice to accept flags which have not been defined, but in some cases might be risky if fore example someone has a typo in a flag.

For example look at the following (contrived) example:

;; this command deletes the given argument
(def delete identity)

(cli/dispatch*
 {:command #'delete
  :flags ["-v, --verbose" "Increases verbosity"
          "--dry-run"     "Simulate but do not action"
          "--input FILE" "Specify the input file/folder"
          "--env=<dev|prod|test>" {:doc "Select an environment" :default "prod"}]}
;; typo in --dryrun (the correct should be --dry-run)
 ["--input" "all-my-data" "--dryrun"])

;; => {:lambdaisland.cli/sources
;;     {:env "--env=<dev|prod|test> (default value)",
;;      :input "--input command line flag"},
;;     :env "prod",
;;     :lambdaisland.cli/argv [],
;;     :input "all-my-data",
;;     :dryrun 1}

In this example the user might thing that he provided the --dryrun argument, the dispatcher will just dispatch as a new flag ignoring the fact that it was an unintentional mistake and because delete doesn't see the flag :dry-run true it will perform the actual delete.

Is there a way to add a :strict-mode true and fail on undefined flags?

Start at the cli/dispatch* entry point shown in the example and trace how undefined arguments become entries in the dispatched result. Define the expected strict-mode behavior for unknown flags, then add coverage for the typo case and confirm that valid flags still work.