Auto merge of rust-lang#253 - codehearts:watch-completion-message, r=fmoko

feat: Show a completion message when watching

The completion message is shown only once all exercises succeed and are
not annotated with "I AM NOT DONE." The watch command will also exit

closes rust-lang#251

Let me know if there are any tests I could add or if the completion message should be tweaked!

Author: bors

src/main.rs

@@ -2,6 +2,7 @@ use crate::exercise::{Exercise, ExerciseList};
 use crate::run::run;
 use crate::verify::verify;
 use clap::{crate_version, App, Arg, SubCommand};
+use console::Emoji;
 use notify::DebouncedEvent;
 use notify::{RecommendedWatcher, RecursiveMode, Watcher};
 use std::ffi::OsStr;
@@ -102,7 +103,21 @@ fn main() {
     }
 
     if matches.subcommand_matches("watch").is_some() {
-        watch(&exercises).unwrap();
+        if watch(&exercises).is_ok() {
+            println!(
+                "{emoji} All exercises completed! {emoji}",
+                emoji = Emoji("🎉", "★")
+            );
+            println!("");
+            println!("We hope you enjoyed learning about the various aspects of Rust!");
+            println!(
+                "If you noticed any issues, please don't hesitate to report them to our repo."
+            );
+            println!("You can also contribute your own exercises to help the greater community!");
+            println!("");
+            println!("Before reporting an issue or contributing, please read our guidelines:");
+            println!("https://github.com/rust-lang/rustlings/blob/master/CONTRIBUTING.md");
+        }
     }
 
     if matches.subcommand_name().is_none() {
@@ -144,10 +159,12 @@ fn watch(exercises: &[Exercise]) -> notify::Result<()> {
     watcher.watch(Path::new("./exercises"), RecursiveMode::Recursive)?;
 
     clear_screen();
-    let verify_result = verify(exercises.iter());
 
     let to_owned_hint = |t: &Exercise| t.hint.to_owned();
-    let failed_exercise_hint = Arc::new(Mutex::new(verify_result.map_err(to_owned_hint).err()));
+    let failed_exercise_hint = match verify(exercises.iter()) {
+        Ok(_) => return Ok(()),
+        Err(exercise) => Arc::new(Mutex::new(Some(to_owned_hint(exercise)))),
+    };
     spawn_watch_shell(&failed_exercise_hint);
     loop {
         match rx.recv() {
@@ -159,9 +176,13 @@ fn watch(exercises: &[Exercise]) -> notify::Result<()> {
                             .iter()
                             .skip_while(|e| !filepath.ends_with(&e.path));
                         clear_screen();
-                        let verify_result = verify(pending_exercises);
-                        let mut failed_exercise_hint = failed_exercise_hint.lock().unwrap();
-                        *failed_exercise_hint = verify_result.map_err(to_owned_hint).err();
+                        match verify(pending_exercises) {
+                            Ok(_) => return Ok(()),
+                            Err(exercise) => {
+                                let mut failed_exercise_hint = failed_exercise_hint.lock().unwrap();
+                                *failed_exercise_hint = Some(to_owned_hint(exercise));
+                            }
+                        }
                     }
                 }
                 _ => {}