feat(cli): better version information

Versions were broken: `cargo hax -V` was displaying the latest tag
attached to the commit. So newer commits on main were tagged
`v0.1.0-alpha`.

Also, if hax is built without git, the version was empty. Now we use
`CARGO_PKG_VERSION` as a fallback.

hax-types/build.rs

@@ -1,24 +1,43 @@
-macro_rules! set_empty_env_var_with_git {
-    ($var:literal, $args: expr) => {
-        if let None = option_env!($var) {
-            println!(
-                "cargo:rustc-env={}={}",
-                $var,
-                std::process::Command::new("git")
-                    .args($args)
-                    .output()
-                    .map(|output| String::from_utf8(output.stdout).unwrap())
-                    .unwrap_or("unknown".into())
-            );
-        }
+macro_rules! set_empty_env_var_with {
+    ($var:literal, $f: expr) => {{
         println!("cargo:rurun-if-env-changed={}", $var);
-    };
+        match option_env!($var) {
+            Some(value) => value.to_string(),
+            None => {
+                let value = $f;
+                println!("cargo:rustc-env={}={}", $var, value);
+                value
+            }
+        }
+    }};
+}
+
+const UNKNOWN: &str = "unknown";
+
+fn git_command(args: &[&str]) -> String {
+    std::process::Command::new("git")
+        .args(args)
+        .output()
+        .map(|output| String::from_utf8(output.stdout).unwrap().trim().to_string())
+        .ok()
+        .filter(|s| !s.is_empty())
+        .unwrap_or(UNKNOWN.to_string())
 }
 
 fn main() {
-    set_empty_env_var_with_git!(
-        "HAX_GIT_DESCRIBE",
-        ["describe", "--tags", "--always", "--abbrev=0"]
-    );
-    set_empty_env_var_with_git!("HAX_GIT_COMMIT_HASH", ["rev-parse", "HEAD"]);
+    let commit_hash =
+        set_empty_env_var_with!("HAX_GIT_COMMIT_HASH", git_command(&["rev-parse", "HEAD"]));
+
+    set_empty_env_var_with!("HAX_VERSION", {
+        if commit_hash == UNKNOWN {
+            env!("CARGO_PKG_VERSION").into()
+        } else {
+            git_command(&["tag", "--contains", &commit_hash])
+                .lines()
+                .next()
+                .and_then(|tag| tag.split_once("hax-v"))
+                .map(|(_, version)| version.trim().to_string())
+                .unwrap_or_else(|| format!("untagged-git-rev-{}", &commit_hash[0..10]))
+        }
+    });
 }

hax-types/src/cli_options/mod.rs

@@ -405,7 +405,14 @@ pub enum ExportBodyKind {
 
 #[derive_group(Serializers)]
 #[derive(JsonSchema, Parser, Debug, Clone)]
-#[command(author, version = concat!("commit=", env!("HAX_GIT_COMMIT_HASH"), " ", "describe=", env!("HAX_GIT_DESCRIBE")), name = "hax", about, long_about = None)]
+#[command(
+    author,
+    version = crate::HAX_VERSION,
+    long_version = concat!("\nversion=", env!("HAX_VERSION"), "\n", "commit=", env!("HAX_GIT_COMMIT_HASH")),
+    name = "hax",
+    about,
+    long_about = None
+)]
 pub struct ExtensibleOptions<E: Extension> {
     /// Replace the expansion of each macro matching PATTERN by their
     /// invocation. PATTERN denotes a rust path (i.e. `A::B::c`) in

hax-types/src/lib.rs

@@ -25,3 +25,6 @@ pub mod driver_api;
 /// The types used to communicate between `cargo-hax` and
 /// `hax-engine`.
 pub mod engine_api;
+
+/// Compile-time version of hax
+pub const HAX_VERSION: &str = env!("HAX_VERSION");