git-sugpatch: Print error and exit on `Config::get` error

Add `exitcode` to exit with an appropriate code.

Add the `gseprintln` macro to wrap `eprintln!()`, prefixing the output
with "error: ".

4 files changed, 27 insertions, 1 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 4be1b47..f0130fe 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -174,6 +174,12 @@ dependencies = [
 ]
 
 [[package]]
+name = "exitcode"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "de853764b47027c2e862a995c34978ffa63c1501f2e15f987ba11bd4f9bba193"
+
+[[package]]
 name = "fnv"
 version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -285,6 +291,7 @@ dependencies = [
 name = "github-suggestion-cli"
 version = "0.0.1"
 dependencies = [
+ "exitcode",
  "getopts",
  "git2",
  "github-suggestion",
diff --git a/Cargo.toml b/Cargo.toml
index d0ce530..dccaa62 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.0.1"
 edition = "2018"
 
 [dependencies]
+exitcode = "1.1.2"
 getopts = "0.2.21"
 git2 = "0.13.8"
 regex = "1.3.9"
diff --git a/src/bin/git-sugpatch.rs b/src/bin/git-sugpatch.rs
index 04b687d..0159307 100644
--- a/src/bin/git-sugpatch.rs
+++ b/src/bin/git-sugpatch.rs
@@ -1,7 +1,10 @@
 use std::env;
 use std::process;
 
+use exitcode;
+
 use github_suggestion::{Client, Suggestion, SuggestionUrl};
+use github_suggestion_cli::gseprintln;
 use github_suggestion_cli::config::Config;
 use github_suggestion_cli::error::Error;
 use github_suggestion_cli::is_suggestion_id;
@@ -10,7 +13,14 @@ use github_suggestion_cli::is_suggestion_id;
 fn main() {
     let args: Vec<_> = env::args().collect();
 
-    let config = Config::get(&args).unwrap();
+    let config = match Config::get(&args) {
+        Ok(c) => c,
+        Err(e) => {
+            gseprintln!(e);
+
+            process::exit(exitcode::DATAERR);
+        },
+    };
 
     if config.suggestions.is_empty() {
         process::exit(111);
diff --git a/src/error.rs b/src/error.rs
index c857bd2..bcca3e1 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -7,3 +7,11 @@ pub enum Error {
     #[error("Unable to parse regex")]
     Regex(#[from] regex::Error),
 }
+
+
+#[macro_export]
+macro_rules! gseprintln {
+    ($arg:expr) => ({
+        eprintln!("error: {}", $arg);
+    })
+}