fix: panic on invalid shell

crates/bws/Cargo.toml

@@ -44,6 +44,7 @@ toml = "0.8.10"
 uuid = { version = "^1.7.0", features = ["serde"] }
 
 bitwarden = { workspace = true, features = ["secrets"] }
+which = "6.0.0"
 
 [dev-dependencies]
 tempfile = "3.10.0"

crates/bws/src/main.rs

@@ -27,6 +27,7 @@ mod state;
 use config::ProfileKey;
 use render::{serialize_response, Color, Output};
 use uuid::Uuid;
+use which::which;
 
 #[derive(Parser, Debug)]
 #[command(name = "bws", version, about = "Bitwarden Secrets CLI", long_about = None)]
@@ -639,6 +640,19 @@ async fn process_commands() -> Result<()> {
             no_inherit_env,
             project_id,
         } => {
+            let shell = match std::env::consts::OS {
+                os if os == "linux" || os == "macos" || os.contains("bsd") => {
+                    shell.unwrap_or_else(|| "sh".to_string())
+                }
+                "windows" => shell.unwrap_or_else(|| "powershell".to_string()),
+                _ => unreachable!(),
+            };
+
+            if !which(&shell).is_ok() {
+                eprintln!("Error: shell '{}' not found", shell);
+                std::process::exit(1);
+            }
+
             let user_command = if command.is_empty() {
                 if atty::is(Stream::Stdin) {
                     eprintln!("{}", Cli::command().render_help().ansi());
@@ -693,14 +707,6 @@ async fn process_commands() -> Result<()> {
                 }
             }
 
-            let shell = match std::env::consts::OS {
-                os if os == "linux" || os == "macos" || os.contains("bsd") => {
-                    shell.unwrap_or_else(|| "sh".to_string())
-                }
-                "windows" => shell.unwrap_or_else(|| "powershell".to_string()),
-                _ => unreachable!(),
-            };
-
             let mut command = process::Command::new(shell);
             command
                 .arg("-c")