rm: implement From for InteractiveMode

Author: cakebaker

src/uu/rm/locales/en-US.ftl

@@ -32,7 +32,6 @@ rm-help-verbose = explain what is being done
 # Error messages
 rm-error-missing-operand = missing operand
   Try '{$util_name} --help' for more information.
-rm-error-invalid-interactive-argument = Invalid argument to interactive ({$arg})
 rm-error-cannot-remove-no-such-file = cannot remove {$file}: No such file or directory
 rm-error-cannot-remove-permission-denied = cannot remove {$file}: Permission denied
 rm-error-cannot-remove-is-directory = cannot remove {$file}: Is a directory

src/uu/rm/locales/fr-FR.ftl

@@ -32,7 +32,6 @@ rm-help-verbose = expliquer ce qui est fait
 # Messages d'erreur
 rm-error-missing-operand = opérande manquant
   Essayez '{$util_name} --help' pour plus d'informations.
-rm-error-invalid-interactive-argument = Argument invalide pour interactive ({$arg})
 rm-error-cannot-remove-no-such-file = impossible de supprimer {$file} : Aucun fichier ou répertoire de ce type
 rm-error-cannot-remove-permission-denied = impossible de supprimer {$file} : Permission refusée
 rm-error-cannot-remove-is-directory = impossible de supprimer {$file} : C'est un répertoire

src/uu/rm/src/rm.rs

@@ -29,8 +29,6 @@ use uucore::{format_usage, os_str_as_bytes, prompt_yes, show_error};
 enum RmError {
     #[error("{}", translate!("rm-error-missing-operand", "util_name" => uucore::execution_phrase()))]
     MissingOperand,
-    #[error("{}", translate!("rm-error-invalid-interactive-argument", "arg" => _0.clone()))]
-    InvalidInteractiveArgument(String),
     #[error("{}", translate!("rm-error-cannot-remove-no-such-file", "file" => _0.quote()))]
     CannotRemoveNoSuchFile(String),
     #[error("{}", translate!("rm-error-cannot-remove-permission-denied", "file" => _0.quote()))]
@@ -61,6 +59,20 @@ pub enum InteractiveMode {
     PromptProtected,
 }
 
+// We implement `From` instead of `TryFrom` because clap guarantees that we only receive valid values.
+//
+// The `PromptProtected` variant is not supposed to be created from a string.
+impl From<&str> for InteractiveMode {
+    fn from(s: &str) -> Self {
+        match s {
+            "never" => Self::Never,
+            "once" => Self::Once,
+            "always" => Self::Always,
+            _ => unreachable!("should be prevented by clap"),
+        }
+    }
+}
+
 /// Options for the `rm` command
 ///
 /// All options are public so that the options can be programmatically
@@ -167,14 +179,7 @@ pub fn uumain(args: impl uucore::Args) -> UResult<()> {
             } else if matches.get_flag(OPT_PROMPT_ONCE) {
                 InteractiveMode::Once
             } else if matches.contains_id(OPT_INTERACTIVE) {
-                match matches.get_one::<String>(OPT_INTERACTIVE).unwrap().as_str() {
-                    "never" => InteractiveMode::Never,
-                    "once" => InteractiveMode::Once,
-                    "always" => InteractiveMode::Always,
-                    val => {
-                        return Err(RmError::InvalidInteractiveArgument(val.to_string()).into());
-                    }
-                }
+                InteractiveMode::from(matches.get_one::<String>(OPT_INTERACTIVE).unwrap().as_str())
             } else {
                 InteractiveMode::PromptProtected
             }