Include git hash in `bat -V` and `bat --version` output if present

I had to use a `lazy_static` due to that the clap API that only accepts a
reference to a version string. And, in our code, only a 'static reference to a
version string.

Code could probably be refactored to accept a "normal" reference, but that would
be a major undertaking.

CHANGELOG.md

@@ -20,6 +20,7 @@
 
 - Add PowerShell completion, see #1826 (@rashil2000)
 - Minimum supported Rust version (MSRV) bumped to 1.46
+- Include git hash in `bat -V` and `bat --version` output if present. See #1921 (@Enselic)
 
 ## Syntaxes
 

src/bin/bat/clap_app.rs

@@ -2,6 +2,21 @@ use clap::{crate_name, crate_version, App as ClapApp, AppSettings, Arg, ArgGroup
 use std::env;
 use std::path::Path;
 
+lazy_static::lazy_static! {
+    static ref VERSION: String = {
+        #[cfg(feature = "bugreport")]
+        let git_version = bugreport::git_version!(fallback = "");
+        #[cfg(not(feature = "bugreport"))]
+        let git_version = "";
+
+        if git_version.is_empty() {
+            crate_version!().to_string()
+        } else {
+            format!("{} ({})", crate_version!(), git_version)
+        }
+    };
+}
+
 pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
     let clap_color_setting = if interactive_output && env::var_os("NO_COLOR").is_none() {
         AppSettings::ColoredHelp
@@ -10,7 +25,7 @@ pub fn build_app(interactive_output: bool) -> ClapApp<'static, 'static> {
     };
 
     let mut app = ClapApp::new(crate_name!())
-        .version(crate_version!())
+        .version(VERSION.as_str())
         .global_setting(clap_color_setting)
         .global_setting(AppSettings::DeriveDisplayOrder)
         .global_setting(AppSettings::UnifiedHelpMessage)