fix: exit with code 127 on command not found (#98)

src/shell/commands/executable.rs

@@ -4,11 +4,17 @@ use crate::shell::types::ShellState;
 use crate::ExecuteResult;
 use crate::ShellCommand;
 use crate::ShellCommandContext;
-use anyhow::bail;
 use anyhow::Result;
 use futures::future::LocalBoxFuture;
 use futures::FutureExt;
 
+/// Errors for executable commands.
+#[derive(Debug, PartialEq)]
+enum ExecutableCommandError {
+  CommandNotFound,
+  CommandEmpty,
+}
+
 /// Command that resolves the command name and
 /// executes it in a separate process.
 pub struct ExecutableCommand {
@@ -34,8 +40,14 @@ impl ShellCommand for ExecutableCommand {
           Ok(std::env::current_exe()?)
         }) {
           Ok(command_path) => command_path,
-          Err(err) => {
-            let _ = stderr.write_line(&err.to_string());
+          Err(ExecutableCommandError::CommandNotFound) => {
+            let _ = stderr
+              .write_line(&format!("{}: command not found", command_name));
+            // Use the Exit status that is used in bash: https://www.gnu.org/software/bash/manual/bash.html#Exit-Status
+            return ExecuteResult::Continue(127, Vec::new(), Vec::new());
+          }
+          Err(ExecutableCommandError::CommandEmpty) => {
+            let _ = stderr.write_line("command name was empty");
             return ExecuteResult::Continue(1, Vec::new(), Vec::new());
           }
         };
@@ -90,9 +102,9 @@ fn resolve_command_path(
   command_name: &str,
   state: &ShellState,
   current_exe: impl FnOnce() -> Result<PathBuf>,
-) -> Result<PathBuf> {
+) -> Result<PathBuf, ExecutableCommandError> {
   if command_name.is_empty() {
-    bail!("command name was empty");
+    return Err(ExecutableCommandError::CommandEmpty);
   }
 
   // Special handling to use the current executable for deno.
@@ -174,8 +186,7 @@ fn resolve_command_path(
       }
     }
   }
-
-  bail!("{}: command not found", command_name)
+  Err(ExecutableCommandError::CommandNotFound)
 }
 
 #[cfg(test)]
@@ -200,4 +211,21 @@ mod local_test {
     .unwrap();
     assert_eq!(path, PathBuf::from("/bin/deno.exe"));
   }
+
+  #[test]
+  fn should_error_on_unknown_command() {
+    let state = ShellState::new(
+      Default::default(),
+      &std::env::current_dir().unwrap(),
+      Default::default(),
+    );
+    // Command not found
+    let result =
+      resolve_command_path("foobar", &state, || Ok(PathBuf::from("/bin/deno")));
+    assert_eq!(result, Err(ExecutableCommandError::CommandNotFound));
+    // Command empty
+    let result =
+      resolve_command_path("", &state, || Ok(PathBuf::from("/bin/deno")));
+    assert_eq!(result, Err(ExecutableCommandError::CommandEmpty));
+  }
 }

src/shell/test.rs

@@ -113,7 +113,7 @@ async fn commands() {
     .command("deno eval 'console.log(1)'")
     .env_var("PATH", "")
     .assert_stderr("deno: command not found\n")
-    .assert_exit_code(1)
+    .assert_exit_code(127)
     .run()
     .await;