fix(mge/jit): error out if dump bn in training mode

GitOrigin-RevId: edc7ea2962da24c8a680c0c6fb2effcfaf3508c2

imperative/python/megengine/jit/tracing.py

@@ -36,7 +36,7 @@ from ..core._imperative_rt.ops import (
 )
 from ..core._trace_option import set_symbolic_shape
 from ..core._wrap import device as as_device
-from ..core.ops.builtin import BackwardGraph, OpDef
+from ..core.ops.builtin import BackwardGraph, BatchNorm, OpDef
 from ..core.ops.special import Const
 from ..core.tensor import megbrain_graph as G
 from ..core.tensor.utils import setscalar
@@ -833,6 +833,10 @@ class trace:
             if isinstance(op, BackwardGraph):
                 ovars = G.apply_backward_varnode(op, *ivars)
             else:
+                if isinstance(op, BatchNorm):
+                    assert (
+                        op.fwd_mode == BatchNorm.FwdMode.INFERENCE
+                    ), "can not dump BatchNorm in training mode, maybe you forget to do model.eval()?"
                 ovars = G.apply_normal_varnode(op, *ivars)
 
             AutoNaming.record_opnode(ovars[0].op)

imperative/python/test/integration/test_trace_dump.py

@@ -11,6 +11,7 @@ import os
 import tempfile
 
 import numpy as np
+import pytest
 
 import megengine as mge
 import megengine.functional as F
@@ -140,3 +141,15 @@ def test_xornet_trace_dump():
 
     with mkstemp() as out:
         pred_fun.dump(out, arg_names=["data"], output_names=["label"])
+
+
+def test_dump_bn_train_mode():
+    @trace(symbolic=True, capture_as_const=True)
+    def bn_train(data):
+        pred = M.BatchNorm2d(10)(data).sum()
+        return pred
+
+    data = mge.tensor(np.random.random((10, 10, 10, 10)))
+    bn_train(data)
+    with pytest.raises(AssertionError):
+        bn_train.dump("test.mge")