Show [name] for optional positionals, allow filtering import by name too

The custom --help renderer showed every positional as <name> regardless
of whether it was actually required, which was misleading for open and
transfer (both take an optional profile name). positional_args() now
checks Arg::is_required_set() and renders [name] for an optional one.

transfer's name positional previously only worked with --export and was
rejected outright when combined with --import. It now filters --import
the same way: 'porthole transfer <name> -i file.toml' imports just that
one profile out of the file instead of everything in it, erroring with
a new TransferProfileNotFound if the file doesn't contain it.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/cli.rs

@@ -188,7 +188,7 @@ pub struct WipeArgs {
 
 #[derive(Args)]
 pub struct TransferArgs {
-    /// Name of the profile to export; every saved profile if omitted. Not used for import.
+    /// Restrict export/import to just this profile; every profile in scope if omitted.
     pub name: Option<String>,
 
     /// Export saved profiles to a file.

src/commands/transfer.rs

@@ -19,9 +19,8 @@ pub fn run(args: TransferArgs) -> Result<()> {
     match (&args.export, &args.import) {
         (Some(_), Some(_)) => Err(PortholeError::TransferConflictingMode),
         (None, None) => Err(PortholeError::TransferNoMode),
-        (None, Some(_)) if args.name.is_some() => Err(PortholeError::TransferNameWithImport),
         (Some(path), None) => export(path, args.name.as_deref()),
-        (None, Some(path)) => import(path),
+        (None, Some(path)) => import(path, args.name.as_deref()),
     }
 }
 
@@ -48,22 +47,34 @@ fn export(path: &str, name: Option<&str>) -> Result<()> {
     Ok(())
 }
 
-fn import(path: &str) -> Result<()> {
+fn import(path: &str, name: Option<&str>) -> Result<()> {
     let text = std::fs::read_to_string(path)?;
     let file: TransferFile = toml::from_str(&text)?;
 
-    for p in &file.profiles {
+    let selected = match name {
+        Some(n) => {
+            let n = profile::normalize(n);
+            let found = file.profiles.into_iter().find(|p| p.name == n);
+            vec![found.ok_or(PortholeError::TransferProfileNotFound(n))?]
+        }
+        None => file.profiles,
+    };
+
+    for p in &selected {
         profile::require_valid_name(&p.name)?;
         if profile::exists(&p.name) {
             return Err(PortholeError::AlreadyExists(p.name.clone()));
         }
     }
-    for p in &file.profiles {
+    for p in &selected {
         profile::save(p)?;
     }
 
-    ui::ok(&format!("Imported {} profile(s) from '{path}'.", file.profiles.len()));
-    warn_about_missing_identities(&file.profiles);
+    match name {
+        Some(n) => ui::ok(&format!("Imported profile '{n}' from '{path}'.")),
+        None => ui::ok(&format!("Imported {} profile(s) from '{path}'.", selected.len())),
+    }
+    warn_about_missing_identities(&selected);
     Ok(())
 }
 

src/error.rs

@@ -35,8 +35,8 @@ pub enum PortholeError {
     #[error("only one of -i/--import, -e/--export may be given")]
     TransferConflictingMode,
 
-    #[error("a profile name only applies to -e/--export, not -i/--import")]
-    TransferNameWithImport,
+    #[error("'{0}' not found in the transfer file")]
+    TransferProfileNotFound(String),
 
     #[error("nothing to do: {0}")]
     NothingToDo(String),

src/main.rs

@@ -139,10 +139,15 @@ fn print_full_help() {
     }
 }
 
-/// `<name>` for each positional arg of `cmd`, space-joined and colored cyan.
+/// `<name>` for each required positional arg of `cmd`, `[name]` for an
+/// optional one, space-joined and colored cyan.
 fn positional_args(cmd: &clap::Command) -> String {
     cmd.get_positionals()
-        .map(|a| ui::cyan(&format!("<{}>", a.get_id().as_str())))
+        .map(|a| {
+            let id = a.get_id().as_str();
+            let text = if a.is_required_set() { format!("<{id}>") } else { format!("[{id}]") };
+            ui::cyan(&text)
+        })
         .collect::<Vec<_>>()
         .join(" ")
 }