From 616d324cd76d81bb1bb3abc5ce9212f1877b463c Mon Sep 17 00:00:00 2001
From: Casey Rodarmor <casey@rodarmor.com>
Date: Sun, 7 May 2017 15:11:10 -0700
Subject: [PATCH] Error if running default recipe that requires arguments
 (#194)

---
 src/app.rs | 9 +++++++--
 src/lib.rs | 6 +++---
 2 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/src/app.rs b/src/app.rs
index 594f8b3..3d6d7da 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -7,7 +7,7 @@ use ::prelude::*;
 use std::{convert, ffi};
 use std::collections::BTreeMap;
 use self::clap::{App, Arg, ArgGroup, AppSettings};
-use super::{Slurp, RunOptions, compile, DEFAULT_SHELL};
+use super::{Slurp, RunOptions, compile, DEFAULT_SHELL, maybe_s};
 
 macro_rules! warn {
   ($($arg:tt)*) => {{
@@ -334,7 +334,12 @@ pub fn app() {
   let arguments = if !rest.is_empty() {
     rest
   } else if let Some(recipe) = justfile.first() {
-    vec![recipe]
+    let min_arguments = recipe.min_arguments();
+    if min_arguments > 0 {
+      die!("Recipe `{}` cannot be used as default recipe since it requires at least {} argument{}.",
+           recipe.name, min_arguments, maybe_s(min_arguments));
+    }
+    vec![recipe.name]
   } else {
     die!("Justfile contains no recipes.");
   };
diff --git a/src/lib.rs b/src/lib.rs
index 4d61d96..2b2acb0 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1169,8 +1169,8 @@ struct RunOptions<'a> {
 }
 
 impl<'a, 'b> Justfile<'a> where 'a: 'b {
-  fn first(&self) -> Option<&'a str> {
-    let mut first: Option<&Recipe<'a>> = None;
+  fn first(&self) -> Option<&Recipe> {
+    let mut first: Option<&Recipe> = None;
     for recipe in self.recipes.values() {
       if let Some(first_recipe) = first {
         if recipe.line_number < first_recipe.line_number {
@@ -1180,7 +1180,7 @@ impl<'a, 'b> Justfile<'a> where 'a: 'b {
         first = Some(recipe);
       }
     }
-    first.map(|recipe| recipe.name)
+    first
   }
 
   fn count(&self) -> usize {