feat: add CLI asset generation for shell completions and man page

src/cli_assets.rs

@@ -0,0 +1,74 @@
+//! Generation helpers for CLI man pages and shell completions.
+
+use crate::cli::Cli;
+use anyhow::{Context, Result};
+use clap::CommandFactory;
+use clap_complete::Shell;
+use std::fs;
+use std::path::Path;
+
+const BIN_NAME: &str = "depot";
+
+/// Generate all supported shell completion scripts and a man page into `out_dir`.
+pub fn generate_cli_assets(out_dir: &Path) -> Result<()> {
+    fs::create_dir_all(out_dir)
+        .with_context(|| format!("Failed to create output directory {}", out_dir.display()))?;
+
+    generate_completion(out_dir, Shell::Bash, "depot.bash")?;
+    generate_completion(out_dir, Shell::Zsh, "_depot")?;
+    generate_completion(out_dir, Shell::Fish, "depot.fish")?;
+    generate_man_page(out_dir, "depot.1")?;
+    Ok(())
+}
+
+fn command_for_generation() -> clap::Command {
+    Cli::command().name(BIN_NAME)
+}
+
+fn generate_completion(out_dir: &Path, shell: Shell, filename: &str) -> Result<()> {
+    let mut command = command_for_generation();
+    let output_path = out_dir.join(filename);
+    let mut buffer = Vec::new();
+    clap_complete::generate(shell, &mut command, BIN_NAME, &mut buffer);
+    fs::write(&output_path, buffer).with_context(|| {
+        format!(
+            "Failed to write {} completion to {}",
+            shell,
+            output_path.display()
+        )
+    })?;
+    Ok(())
+}
+
+fn generate_man_page(out_dir: &Path, filename: &str) -> Result<()> {
+    let output_path = out_dir.join(filename);
+    let mut buffer = Vec::new();
+    clap_mangen::Man::new(command_for_generation())
+        .render(&mut buffer)
+        .context("Failed to render clap man page")?;
+    fs::write(&output_path, buffer)
+        .with_context(|| format!("Failed to write man page {}", output_path.display()))?;
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn generate_cli_assets_writes_expected_files() {
+        let temp = tempfile::tempdir().unwrap();
+        generate_cli_assets(temp.path()).unwrap();
+
+        let bash = temp.path().join("depot.bash");
+        let zsh = temp.path().join("_depot");
+        let fish = temp.path().join("depot.fish");
+        let man = temp.path().join("depot.1");
+
+        assert!(bash.exists());
+        assert!(zsh.exists());
+        assert!(fish.exists());
+        assert!(man.exists());
+        assert!(!std::fs::read_to_string(&man).unwrap().is_empty());
+    }
+}