fix(providers): make exporter de-registration explicit + the invariant robust

fluid_build/providers/odps/__init__.py

@@ -24,4 +24,7 @@
 # DIRECTLY:  from fluid_build.providers.odps.odps import OdpsProvider
 # (see cli/odps.py, cli/export_odps.py, cli/generate_standard.py). This package
 # __init__ deliberately exposes no BaseProvider subclass, so the provider
-# auto-discovery scan cannot re-register it.
+# auto-discovery scan cannot re-register it — and we ALSO set the explicit
+# opt-out below (consistent with the odcs / odps_standard sibling packages) so a
+# future refactor that re-exposed the class here can't silently re-register it.
+__fluid_no_autoregister__ = True

fluid_build/providers/odps_standard/__init__.py

@@ -25,5 +25,11 @@
 # them DIRECTLY:  from fluid_build.providers.odps_standard import (
 #     BitolOdpsProvider, OdpsStandardProvider)
 # (see cli/odps.py, cli/odps_standard.py, cli/generate_standard.py).
+#
+# Set the opt-out EXPLICITLY (like the odps/odcs sibling packages) rather than
+# relying on the accident that this module exposes two BaseProvider subclasses
+# and so escapes the single-subclass auto-register fallback. Otherwise a future
+# refactor that left a single exporter class here would silently re-register it.
+__fluid_no_autoregister__ = True
 
 __all__ = ["BitolOdpsProvider", "OdpsStandardProvider"]

tests/providers/test_no_exporter_providers.py

@@ -31,6 +31,11 @@
     "does not support apply",
     "export action acknowledged",
     "use render() for actual export",
+    # An apply() whose body is just a refusal is an exporter, not a provider —
+    # cover the common refusal shapes so a future sibling can't slip past with
+    # different wording.
+    "notimplementederror",
+    "not implemented",
 )
 
 
@@ -70,3 +75,22 @@ def test_odcs_exporter_still_importable_directly():
     from fluid_build.providers.odcs import OdcsProvider
 
     assert hasattr(OdcsProvider(), "render")
+
+
+def test_exporter_packages_explicitly_opt_out_of_autoregistration():
+    # The exporter packages must de-register EXPLICITLY (set
+    # __fluid_no_autoregister__), not rely on incidental properties of their
+    # module namespace (e.g. exposing >1 BaseProvider subclass). Otherwise a
+    # refactor could silently re-register them as providers.
+    import importlib
+
+    for modname in (
+        "fluid_build.providers.odps",
+        "fluid_build.providers.odcs",
+        "fluid_build.providers.odps_standard",
+    ):
+        mod = importlib.import_module(modname)
+        assert getattr(mod, "__fluid_no_autoregister__", False) is True, (
+            f"{modname} must set __fluid_no_autoregister__ = True (it is an exporter, "
+            "not a provider) instead of relying on auto-discovery accidents"
+        )