build(cli): get build sha via git command

cli/build.rs

@@ -1,8 +1,7 @@
 use std::{
     env,
-    ffi::OsStr,
-    fs,
     path::{Path, PathBuf},
+    process::Command,
     time::SystemTime,
 };
 
@@ -62,81 +61,23 @@ fn web_playground_files_present() -> bool {
 }
 
 fn read_git_sha() -> Option<String> {
-    let mut repo_path = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
+    let crate_path = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap());
 
-    let mut git_path;
-    loop {
-        git_path = repo_path.join(".git");
-        if git_path.exists() {
-            break;
-        }
-        if !repo_path.pop() {
-            return None;
-        }
-    }
-
-    let git_dir_path;
-    if git_path.is_dir() {
-        git_dir_path = git_path;
-    } else if let Ok(git_path_content) = fs::read_to_string(&git_path) {
-        git_dir_path = repo_path.join(git_path_content.get("gitdir: ".len()..).unwrap().trim_end());
-    } else {
+    if !crate_path
+        .parent()
+        .map_or(false, |p| p.join(".git").is_dir())
+    {
         return None;
     }
-    let git_head_path = git_dir_path.join("HEAD");
-    if let Some(path) = git_head_path.to_str() {
-        println!("cargo:rerun-if-changed={path}");
-    }
-    if let Ok(mut head_content) = fs::read_to_string(&git_head_path) {
-        if head_content.ends_with('\n') {
-            head_content.pop();
-        }
 
-        // If we're on a branch, read the SHA from the ref file.
-        if head_content.starts_with("ref: ") {
-            head_content.replace_range(0.."ref: ".len(), "");
-            let ref_filename = {
-                // Go to real non-worktree gitdir
-                let git_dir_path = git_dir_path
-                    .parent()
-                    .and_then(|p| {
-                        p.file_name()
-                            .map(|n| n == OsStr::new("worktrees"))
-                            .and_then(|x| x.then(|| p.parent()))
-                    })
-                    .flatten()
-                    .unwrap_or(&git_dir_path);
-
-                let file = git_dir_path.join(&head_content);
-                if file.is_file() {
-                    file
-                } else {
-                    let packed_refs = git_dir_path.join("packed-refs");
-                    if let Ok(packed_refs_content) = fs::read_to_string(&packed_refs) {
-                        for line in packed_refs_content.lines() {
-                            if let Some((hash, r#ref)) = line.split_once(' ') {
-                                if r#ref == head_content {
-                                    if let Some(path) = packed_refs.to_str() {
-                                        println!("cargo:rerun-if-changed={path}");
-                                    }
-                                    return Some(hash.to_string());
-                                }
-                            }
-                        }
-                    }
-                    return None;
-                }
-            };
-            if let Some(path) = ref_filename.to_str() {
-                println!("cargo:rerun-if-changed={path}");
+    Command::new("git")
+        .args(["rev-parse", "HEAD"])
+        .current_dir(crate_path)
+        .output()
+        .map_or(None, |output| {
+            if !output.status.success() {
+                return None;
             }
-            return fs::read_to_string(&ref_filename).ok();
-        }
-        // If we're on a detached commit, then the `HEAD` file itself contains the sha.
-        if head_content.len() == 40 {
-            return Some(head_content);
-        }
-    }
-
-    None
+            Some(String::from_utf8_lossy(&output.stdout).to_string())
+        })
 }