refactor

src/plumbing/main.rs

@@ -7,9 +7,8 @@ use std::{
     },
 };
 
-use anyhow::{Context, Result};
+use anyhow::{anyhow, Context, Result};
 use clap::{CommandFactory, Parser};
-use clap_complete::{generate, generate_to};
 use gitoxide_core as core;
 use gitoxide_core::{pack::verify, repository::PathsOrPatterns};
 use gix::bstr::{io::BufReadExt, BString};
@@ -1220,15 +1219,16 @@ pub fn main() -> Result<()> {
                 },
             ),
         },
-        Subcommands::GenerateCompletions { shell, out_dir } => {
+        Subcommands::Completions { shell, out_dir } => {
             let mut app = Args::command();
-
+            let shell = shell
+                .or_else(clap_complete::Shell::from_env)
+                .ok_or_else(|| anyhow!("The shell could not be derived from the environment"))?;
             if let Some(out_dir) = out_dir {
-                generate_to(shell, &mut app, env!("CARGO_PKG_NAME"), &out_dir)?;
+                clap_complete::generate_to(shell, &mut app, env!("CARGO_PKG_NAME"), &out_dir)?;
             } else {
-                generate(shell, &mut app, env!("CARGO_PKG_NAME"), &mut std::io::stdout());
+                clap_complete::generate(shell, &mut app, env!("CARGO_PKG_NAME"), &mut std::io::stdout());
             }
-
             Ok(())
         }
     }?;

src/plumbing/options/mod.rs

@@ -135,13 +135,13 @@ pub enum Subcommands {
     /// Subcommands that need no git repository to run.
     #[clap(subcommand)]
     Free(free::Subcommands),
-    /// Generate shell completions
-    GenerateCompletions {
-        /// Shell for generating completions.
-        #[clap(long, short)]
-        shell: Shell,
-        /// Output directory. If not provided, will write to stdout.
+    /// Generate shell completions to stdout or a directory.
+    #[clap(visible_alias = "generate-completions", visible_alias = "shell-completions")]
+    Completions {
+        /// The shell to generate completions for. Otherwise it's derived from the environment.
         #[clap(long, short)]
+        shell: Option<Shell>,
+        /// The output directory in case multiple files are generated. If not provided, will write to stdout.
         out_dir: Option<String>,
     },
 }