git-sugpatch: Print usage with no suggestion argumenet

Add `Options` to `Config` to allow us to get a usage string from a
`Config` instance, which is where we create `Options`.

Needed to remove the `Debug` derive on `Config` in order to add the
field as `Options` doesn't implement `Debug`.

2 files changed, 13 insertions, 1 deletions

diff --git a/src/bin/git-sugpatch.rs b/src/bin/git-sugpatch.rs
index 9b2769a..c8fc0a8 100644
--- a/src/bin/git-sugpatch.rs
+++ b/src/bin/git-sugpatch.rs
@@ -20,6 +20,11 @@ fn main() {
     };
 
     if config.suggestions.is_empty() {
+        print!(
+            "{}",
+            config.usage("usage: git sugpatch [options] <suggestion>..."),
+        );
+
         process::exit(exitcode::USAGE);
     }
 
diff --git a/src/config.rs b/src/config.rs
index 57a4477..4402014 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -27,11 +27,12 @@ pub enum Error {
     Git(#[from] git2::Error),
 }
 
-#[derive(Debug)]
 pub struct Config {
     pub github_token: String,
     pub o_r: Result<OwnerRepo, owner_repo::Error>,
     pub suggestions: Vec<String>,
+
+    opts: Options,
 }
 
 impl Config {
@@ -53,9 +54,15 @@ impl Config {
             github_token: Self::github_token(&opt_matches, &git_config)?,
             o_r: o_r,
             suggestions: opt_matches.free,
+
+            opts: opts,
         })
     }
 
+    pub fn usage(&self, brief: &str) -> String {
+        self.opts.usage(&brief)
+    }
+
     fn github_token(
         opt_matches: &getopts::Matches,
         git_config: &git2::Config,