fix(build): refresh cached git provenance for server builds

rustfs/build.rs

@@ -12,7 +12,52 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::path::Path;
+use std::process::Command;
+
+fn git(root: &Path, args: &[&str]) -> Option<String> {
+    let output = Command::new("git").args(args).current_dir(root).output().ok()?;
+    output
+        .status
+        .success()
+        .then(|| String::from_utf8_lossy(&output.stdout).trim().to_owned())
+}
+
 fn main() -> shadow_rs::SdResult<()> {
+    let manifest = std::env::var_os("CARGO_MANIFEST_DIR").ok_or("missing CARGO_MANIFEST_DIR")?;
+    let root = Path::new(&manifest).join("..");
+    println!("cargo:rerun-if-changed=build.rs");
+    // Match the E2E build identity's source and configuration inputs.
+    for path in [
+        "crates",
+        "rustfs",
+        "Cargo.toml",
+        "Cargo.lock",
+        "rust-toolchain.toml",
+        ".cargo",
+        ".config",
+    ] {
+        let path = root.join(path);
+        if path.exists() {
+            println!("cargo:rerun-if-changed={}", path.display());
+        }
+    }
+    // Resolve worktree-local HEAD/index and common refs through Git. Watching
+    // refs also covers tags and a new loose ref created from packed refs.
+    for name in ["HEAD", "index", "refs", "packed-refs"] {
+        if let Some(path) = git(&root, &["rev-parse", "--git-path", name]) {
+            let path = Path::new(&path);
+            let path = if path.is_absolute() {
+                path.to_owned()
+            } else {
+                root.join(path)
+            };
+            if path.exists() {
+                println!("cargo:rerun-if-changed={}", path.display());
+            }
+        }
+    }
+
     println!("cargo:rerun-if-env-changed=RUSTFS_BUILD_VERSION");
     if let Ok(version) = std::env::var("RUSTFS_BUILD_VERSION")
         && !version.is_empty()