Fixed Git LFS pointers overwritten as plain Git blobs

.pre-commit-config.yaml

@@ -69,3 +69,10 @@ repos:
       - id: rst-backticks
       - id: rst-directive-colons
       - id: rst-inline-touching-normal
+  - repo: local
+    hooks:
+      - id: check-git-lfs-pointers
+        name: check Git LFS pointers
+        entry: tools/pre_commit/check_git_lfs_pointers.sh
+        language: script
+        pass_filenames: true

tools/pre_commit/check_git_lfs_pointers.sh

@@ -0,0 +1,107 @@
+#!/usr/bin/env bash
+# Copyright (c) 2022-2026, The Isaac Lab Project Developers (https://github.com/isaac-sim/IsaacLab/blob/main/CONTRIBUTORS.md).
+# All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+
+# Pre-commit hook: ensure Git LFS attribute rules match index storage.
+#
+# Paths with filter=lfs in .gitattributes must be staged as LFS pointers, not plain
+# blobs. When many paths are checked (e.g. pre-commit run --all-files), falls back to
+# git lfs fsck --pointers.
+
+set -euo pipefail
+
+# Above this count, per-file index checks are slower than a single fsck over HEAD/index.
+readonly FSCK_FILE_THRESHOLD=200
+
+# --- Prerequisites -----------------------------------------------------------
+# Git LFS must be on PATH; without it, filter=clean/smudge cannot run on commit.
+if ! git lfs version >/dev/null 2>&1; then
+    echo "git-lfs is not installed; install it to work with LFS-tracked files." >&2
+    exit 1
+fi
+
+# --- Helpers: read .gitattributes and index blobs ----------------------------
+
+# Return the "filter" attribute value for a path (e.g. "lfs" or "unspecified").
+lfs_filter_attr() {
+    local path="$1"
+    git check-attr filter -- "${path}" 2>/dev/null | sed -n 's/.*filter: //p' | tr -d ' \r'
+}
+
+# True when the staged blob (":path") is a well-formed LFS pointer file.
+index_blob_is_valid_lfs_pointer() {
+    local path="$1"
+    git show ":${path}" 2>/dev/null | git lfs pointer --check --stdin >/dev/null 2>&1
+}
+
+# True when the staged blob starts with the LFS pointer spec line.
+# Used for the reverse check only: "pointer --check" accepts empty files, which
+# would false-positive on .gitkeep and other zero-byte paths.
+index_blob_has_lfs_pointer_header() {
+    local path="$1"
+    git show ":${path}" 2>/dev/null | head -n1 | grep -qxF 'version https://git-lfs.github.com/spec/v1'
+}
+
+# --- User-facing errors ------------------------------------------------------
+print_fix_hint() {
+    echo >&2
+    echo "For LFS-tracked files, re-add after Git LFS is installed:" >&2
+    echo "  git rm --cached <file> && git add <file>" >&2
+}
+
+# --- Full-repository check (pre-commit run --all-files / many paths) ---------
+# Verifies every path that should use LFS is stored as a pointer in HEAD/index.
+run_fsck() {
+    git lfs fsck --pointers
+}
+
+# --- Incremental check (git commit / small diffs) ------------------------------
+# pre-commit passes staged/changed paths as "$@". For each path in the index:
+#   1. filter=lfs  -> blob must be a valid LFS pointer
+#   2. not filter=lfs but LFS header -> misconfigured .gitattributes
+check_paths() {
+    local path filter_attr
+    local -a error_messages=()
+
+    for path in "$@"; do
+        filter_attr="$(lfs_filter_attr "${path}")"
+        # Skip paths not present in the index (e.g. deleted-only in this commit).
+        if ! git show ":${path}" >/dev/null 2>&1; then
+            continue
+        fi
+
+        if [[ "${filter_attr}" == "lfs" ]]; then
+            if ! index_blob_is_valid_lfs_pointer "${path}"; then
+                error_messages+=(
+                    "  ${path}: has filter=lfs but is staged as a regular Git blob (not an LFS pointer)"
+                )
+            fi
+        elif index_blob_has_lfs_pointer_header "${path}"; then
+            error_messages+=(
+                "  ${path}: is an LFS pointer but is not tracked by filter=lfs in .gitattributes"
+            )
+        fi
+    done
+
+    if [[ "${#error_messages[@]}" -ne 0 ]]; then
+        echo "Git LFS pointer check failed:" >&2
+        printf '%s\n' "${error_messages[@]}" >&2
+        print_fix_hint
+        return 1
+    fi
+    return 0
+}
+
+# --- Entry point -------------------------------------------------------------
+# No args or a large file list -> fsck; otherwise check only the given paths.
+main() {
+    if [[ "$#" -eq 0 ]] || [[ "$#" -gt "${FSCK_FILE_THRESHOLD}" ]]; then
+        run_fsck
+        return
+    fi
+    check_paths "$@"
+}
+
+main "$@"