feat: add shell-hook command

src/cli/mod.rs

@@ -20,6 +20,7 @@ pub mod remove;
 pub mod run;
 pub mod search;
 pub mod shell;
+pub mod shell_hook;
 pub mod task;
 pub mod upload;
 
@@ -58,6 +59,8 @@ pub enum Command {
     Run(run::Args),
     #[clap(alias = "s")]
     Shell(shell::Args),
+    #[clap(hide = true)]
+    ShellHook(shell_hook::Args),
     #[clap(alias = "g")]
     Global(global::Args),
     Auth(auth::Args),
@@ -161,6 +164,7 @@ pub async fn execute_command(command: Command) -> miette::Result<()> {
         Command::Auth(cmd) => auth::execute(cmd).await,
         Command::Install(cmd) => install::execute(cmd).await,
         Command::Shell(cmd) => shell::execute(cmd).await,
+        Command::ShellHook(cmd) => shell_hook::execute(cmd),
         Command::Task(cmd) => task::execute(cmd),
         Command::Info(cmd) => info::execute(cmd).await,
         Command::Upload(cmd) => upload::execute(cmd).await,

src/cli/shell_hook.rs

@@ -0,0 +1,66 @@
+use std::path::PathBuf;
+
+use clap::Parser;
+use miette::IntoDiagnostic;
+use rattler_conda_types::Platform;
+use rattler_shell::{
+    activation::{ActivationVariables, Activator},
+    shell::ShellEnum,
+};
+
+use crate::prefix::Prefix;
+
+/// Print the activation script
+#[derive(Parser, Debug)]
+pub struct Args {
+    /// Sets the shell
+    #[arg(short, long)]
+    shell: Option<ShellEnum>,
+}
+
+/// Generates the activation script.
+fn generate_activation_script(shell: Option<ShellEnum>) -> miette::Result<String> {
+    let prefix = Prefix::new(PathBuf::new())?;
+    let shell = shell.unwrap_or_default();
+    let platform = Platform::current();
+    let activator = Activator::from_path(prefix.root(), shell, platform).into_diagnostic()?;
+    let path = std::env::var("PATH")
+        .ok()
+        .map(|p| std::env::split_paths(&p).collect::<Vec<_>>());
+
+    // If we are in a conda environment, we need to deactivate it before activating the host / build prefix
+    let conda_prefix = std::env::var("CONDA_PREFIX").ok().map(|p| p.into());
+    let result = activator
+        .activation(ActivationVariables {
+            conda_prefix,
+            path,
+            path_modification_behavior: Default::default(),
+        })
+        .into_diagnostic()?;
+
+    Ok(result.script.clone())
+}
+
+/// Prints the activation script to the stdout.
+pub fn execute(args: Args) -> miette::Result<()> {
+    let script = generate_activation_script(args.shell)?;
+    println!("{script}");
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    pub fn test_shell_hook() {
+        let script = generate_activation_script(None).unwrap();
+        if cfg!(unix) {
+            assert!(script.contains("export PATH="));
+            assert!(script.contains("export CONDA_PREFIX="));
+        } else {
+            assert!(script.contains("@SET \"PATH="));
+            assert!(script.contains("@SET \"CONDA_PREFIX="));
+        }
+    }
+}