fix(rvm): make MJ asset revisions immutable

Author: Abecid

examples/train/rvm_h3/01_download_mj_video.sh

@@ -14,9 +14,11 @@ hf_download() {
 
 mkdir -p "${RVM_REWARD_ROOT}"
 
+# These values must match fastvideo/train/methods/rl/rewards/mj_video.py.
+# They are intentionally not environment-overridable for reported runs.
 MJ_VIDEO_SOURCE_COMMIT="cc1d2c9587a620e9ebd3599ae4cdd21b5fd7c87a"
 MJ_VIDEO_MODEL_REVISION="5d32c2416bf5ffb9331a175890744e73defb54c4"
-MJ_VIDEO_BASE_REVISION="${MJ_VIDEO_BASE_REVISION:-e4f6747}"
+MJ_VIDEO_BASE_REVISION="e4f6747"
 
 if [[ ! -d "${MJ_VIDEO_RUNTIME_PATH}/.git" ]]; then
     rm -rf "${MJ_VIDEO_RUNTIME_PATH}"
@@ -45,6 +47,20 @@ require_path "${MJ_VIDEO_MODEL_PATH}/model.safetensors"
 require_path "${MJ_VIDEO_BASE_MODEL_PATH}/config.json"
 require_path "${MJ_VIDEO_BASE_MODEL_PATH}/model.safetensors"
 
+OBSERVED_SOURCE="$(git -C "${MJ_VIDEO_RUNTIME_PATH}" rev-parse HEAD)"
+if [[ "${OBSERVED_SOURCE}" != "${MJ_VIDEO_SOURCE_COMMIT}" ]]; then
+    echo "MJ-VIDEO source revision mismatch: expected ${MJ_VIDEO_SOURCE_COMMIT}, got ${OBSERVED_SOURCE}." >&2
+    exit 1
+fi
+if [[ "$(<"${MJ_VIDEO_MODEL_PATH}/.fastvideo_revision")" != "${MJ_VIDEO_MODEL_REVISION}" ]]; then
+    echo "MJ-VIDEO checkpoint revision marker mismatch." >&2
+    exit 1
+fi
+if [[ "$(<"${MJ_VIDEO_BASE_MODEL_PATH}/.fastvideo_revision")" != "${MJ_VIDEO_BASE_REVISION}" ]]; then
+    echo "InternVL2 base revision marker mismatch." >&2
+    exit 1
+fi
+
 cat <<EOF
 Downloaded:
   MJ-VIDEO code:       ${MJ_VIDEO_RUNTIME_PATH} @ ${MJ_VIDEO_SOURCE_COMMIT}