Add Git information to cargo-gpu's --version CLI subcommand

crates/cargo-gpu/build.rs

@@ -1,12 +1,46 @@
 //! cargo-gpu build script.
 
+use std::ffi::OsStr;
+use std::path::PathBuf;
+
 fn main() {
-    let git_hash = std::process::Command::new("git")
-        .args(["rev-parse", "HEAD"])
+    if let Some(git_directory) = invoke_git(["rev-parse", "--git-dir"]) {
+        println!("cargo:rerun-if-changed={git_directory}/HEAD");
+    }
+
+    let git_rev = invoke_git(["rev-parse", "HEAD"]);
+    let git_date = invoke_git([
+        "show",
+        "-s",
+        "--format=%cd",
+        "--date=format:%Y-%m-%d",
+        "HEAD",
+    ]);
+
+    let postfix = if let Some(git_rev) = git_rev
+        && let Some(git_date) = git_date
+    {
+        let git_rev = git_rev.get(..8).unwrap_or(&git_rev);
+        let git_date = git_date.strip_suffix("\n").unwrap_or(&git_date);
+        format!(" ({git_rev} {git_date})")
+    } else {
+        " (installed from crates.io)".into()
+    };
+    std::fs::write(
+        PathBuf::from(std::env::var("OUT_DIR").unwrap()).join("version_postfix"),
+        postfix,
+    )
+    .unwrap();
+}
+
+fn invoke_git<I, S>(args: I) -> Option<String>
+where
+    I: IntoIterator<Item = S>,
+    S: AsRef<OsStr>,
+{
+    std::process::Command::new("git")
+        .args(args)
         .output()
-        .map_or_else(
-            |_| "unknown".to_owned(),
-            |output| String::from_utf8(output.stdout).unwrap_or_else(|_| "unknown".to_owned()),
-        );
-    println!("cargo:rustc-env=GIT_HASH={git_hash}");
+        .ok()
+        .and_then(|output| String::from_utf8(output.stdout).ok())
 }

crates/cargo-gpu/src/lib.rs

@@ -153,10 +153,17 @@ impl Command {
 
 /// the Cli struct representing the main cli
 #[derive(clap::Parser)]
-#[clap(author, version, about, subcommand_required = true)]
+#[clap(author, version = VERSION, about, subcommand_required = true)]
 #[non_exhaustive]
 pub struct Cli {
     /// The command to run.
     #[clap(subcommand)]
     pub command: Command,
 }
+
+const VERSION: &str = {
+    concat!(
+        env!("CARGO_PKG_VERSION"),
+        include_str!(concat!(env!("OUT_DIR"), "/version_postfix")),
+    )
+};

crates/cargo-gpu/src/show.rs

@@ -20,8 +20,6 @@ pub enum Info {
     CacheDirectory,
     /// The source location of spirv-std
     SpirvSource(SpirvSourceDep),
-    /// The git commitsh of this cli tool.
-    Commitsh,
     /// All the available SPIR-V capabilities that can be set with `--capabilities`
     Capabilities,
 }
@@ -53,9 +51,6 @@ impl Show {
                 let rust_gpu_source = SpirvSource::get_rust_gpu_deps_from_shader(&metadata)?;
                 println!("{rust_gpu_source}\n");
             }
-            Info::Commitsh => {
-                println!("{}", env!("GIT_HASH"));
-            }
             Info::Capabilities => {
                 println!("All available options to the `cargo gpu build --capabilities` argument:");
                 #[expect(