feat: Add dynamic completions in clap library

Fixes #1432

This implements dynamic completions of clap with
https://docs.rs/clap_complete/latest/clap_complete/env/index.html.

It's an unstable-dynamic feature for clap_complete which has to be
explicitly enabled.

Author: Gökhan Kocak

Cargo.lock

@@ -23,7 +23,7 @@ base64 = "0.22"
 bytes = "^1.11"
 chrono = { version = "^0.4", default-features = false, features = ["clock", "serde"] }
 clap = { version = "^4.5", features = ["cargo", "color", "derive", "env"] }
-clap_complete = { version = "^4.5" }
+clap_complete = { version = "^4.5", features = ["unstable-dynamic"] }
 color-eyre = { version = "^0.6", features = ["default", "issue-url", "track-caller"] }
 config = { version = "^0.15", default-features = false }
 derive_builder = { version = "^0.20" }

Cargo.toml

@@ -17,6 +17,8 @@
 //! The binary of the CLI
 #![deny(missing_docs)]
 
+use clap::CommandFactory;
+use clap_complete::CompleteEnv;
 use color_eyre::eyre::{Report, Result};
 use color_eyre::owo_colors::OwoColorize;
 use color_eyre::section::PanicMessage;
@@ -28,7 +30,17 @@ use openstack_cli::error::OpenStackCliError;
 #[tokio::main]
 async fn main() -> Result<(), Report> {
     initialize_panic_handler()?;
-    openstack_cli::entry_point().await?;
+
+    let args = env::args_os();
+    match CompleteEnv::with_factory(openstack_cli::Cli::command).try_complete(args, None) {
+        Ok(true) => {
+            return Ok(());
+        }
+        Ok(false) | Err(_) => {
+            openstack_cli::entry_point().await?;
+        }
+    }
+
     Ok(())
 }