fix: cake serve fails with "required argument was not provided: address"

[SAGAR-TAMANG]

Problem

cake serve <model> does not work in any release build:

$ cake serve evilsocket/Qwen3-0.6B
error: The following required argument was not provided: address

Usage: cake <COMMAND>

For more information, try '--help'.

No combination of flags gets past it — address has a default value in the source, so there is nothing the user can pass to satisfy it.

This affects every release build regardless of feature selection. cake serve is documented in the README and in docs/api.md as the way to start the API server.

Cause

Clap derives an argument's ID from the field name, not from the long attribute. The Serve variant declares a field named address and also flattens Args, which has its own address field:

// cake-cli/src/main.rs:41
Serve {
    #[arg(id = "model_name")]
    model: String,

    #[arg(long = "api", default_value = "0.0.0.0:8080")]
    address: String,              // clap ID: "address", flag: --api

    #[command(flatten)]
    args: Args,                   // Args::address -> ID: "address", flag: --address
},

// cake-core/src/lib.rs:162
#[arg(long, default_value = "0.0.0.0:10128")]
pub address: String,

Both register under the ID "address" in the same command.

Clap validates ID uniqueness with debug assertions, which --release compiles out. Rather than panicking with a clear message, the built command ends up with a malformed argument table: both default values are dropped, address is treated as required, and the usage line degenerates to cake <COMMAND> instead of a real one.

Run is unaffected — it flattens Args without declaring an address field of its own.

Workaround for anyone hitting this

Serve only sets args.api before delegating to the same code path as Run:

Commands::Serve { model, address, mut args } => {
    args.model = model;
    args.api = Some(address);
    args.mode = Mode::Master;
    run_as_master(args).await
}

So this is an exact equivalent and does work today:

cake run <model> --api 0.0.0.0:8080

Fix

Rename the field to api_address, removing the collision:

     #[arg(long = "api", default_value = "0.0.0.0:8080")]
-        address: String,
+        api_address: String,

-        Commands::Serve { model, address, mut args } => {
+        Commands::Serve { model, api_address, mut args } => {
             args.model = model;
-            args.api = Some(address);
+            args.api = Some(api_address);

Renaming was chosen over adding #[arg(id = "...")] because it makes the field name match the flag it produces, so the collision is harder to reintroduce later.

No user-facing flags change: --api and --address continue to behave as documented.

Context

Found while running cake on Android/Termux. The workaround above was verified working on that device; cake run <model> --api 0.0.0.0:8080 serves the OpenAI-compatible API correctly.

Worth noting that no test currently exercises the CLI's argument parsing, which is why a broken headline subcommand could ship. A Cli::command().debug_assert() test would have caught this at build time — clap provides it for exactly this purpose:

#[test]
fn verify_cli() {
    use clap::CommandFactory;
    Cli::command().debug_assert();
}

Happy to add that in a follow-up if it would be welcome.

🤖 Generated with Claude Code