chore: import upstream snapshot with attribution

FlagEmbedding/utils/transformers_compat.py

@@ -0,0 +1,29 @@
+from packaging import version
+import transformers
+
+TF_VER = version.parse(getattr(transformers, "__version__", "0.0.0"))
+IS_TF_V5_OR_HIGHER = TF_VER >= version.parse("5.0.0")
+
+
+# ------------- torch.fx availability -------------
+# v5 removed is_torch_fx_available. We emulate it via feature detection.
+def is_torch_fx_available():
+    try:
+        import torch.fx  # noqa: F401
+
+        return True
+    except Exception:
+        return False
+
+
+# ------------- other utilities that moved -------------
+# Pattern:
+# try the new location first (v5), then fall back to v4 path, else provide a safe default.
+def import_from_candidates(candidates, default=None):
+    for mod, name in candidates:
+        try:
+            module = __import__(mod, fromlist=[name])
+            return getattr(module, name)
+        except Exception:
+            pass
+    return default