composepost: apply add-determinism pyc-zero-mtime

Fixes: ostreedev/ostree#1469

Assuming that add-determinism is installed on the system,
apply add-determinism to set the embedded mtime in all .pyc
files to zero.

Signed-off-by: Luke Yang <[email protected]>
Co-authored-by: Steven Presti <[email protected]>

rust/src/composepost.rs

@@ -1201,7 +1201,18 @@ fn workaround_selinux_cross_labeling_recurse(
 /// This is the nearly the last code executed before we run `ostree commit`.
 pub fn compose_postprocess_final(rootfs_dfd: i32, _treefile: &Treefile) -> CxxResult<()> {
     let rootfs = unsafe { &crate::ffiutil::ffi_dirfd(rootfs_dfd)? };
-
+    if std::process::Command::new("add-determinism").status().expect("Failed to find add-determinism on system.").success() {
+         // add-determinism --handler pyc-zero-mtime
+        let r = std::process::Command::new("add-determinism")
+        .arg("--handler")
+        .arg("pyc-zero-mtime")
+        .arg("/usr")
+        .status()
+        .expect("Failed to normalize .pyc files using add-determinism");
+        if !r.success() {
+            return Err(anyhow!("Failed to execute add-determinism --handler pyc-zero-mtime: {:?}", r).into());
+        }
+    }
     hardlink_rpmdb_base_location(rootfs, None)?;
     Ok(())
 }