fix(mge/trace): fix random op in symbolic trace

GitOrigin-RevId: 9a851cd177119ee43155b831e9622ce342423090

imperative/python/megengine/random/distribution.py

@@ -52,7 +52,8 @@ def normal(
         size = (1,)
     seed = _random_seed_generator().__next__()
     op = GaussianRNG(seed=seed, mean=mean, std=std)
-    size = Tensor(size, dtype="int32")
+    _ref = Tensor([], dtype="int32")
+    size = utils.astensor1d(size, _ref, dtype="int32")
     (output,) = apply(op, size)
     return output
 
@@ -93,7 +94,8 @@ def uniform(
         size = (1,)
     seed = _random_seed_generator().__next__()
     op = UniformRNG(seed=seed)
-    size = Tensor(size, dtype="int32")
+    _ref = Tensor([], dtype="int32")
+    size = utils.astensor1d(size, _ref, dtype="int32")
     (output,) = apply(op, size)
 
     return low + (high - low) * output

imperative/python/test/unit/test_tracing.py

@@ -23,6 +23,7 @@ from megengine.core.tensor.core import apply
 from megengine.core.tensor.raw_tensor import as_raw_tensor
 from megengine.functional import exp, log
 from megengine.jit import exclude_from_trace, trace
+from megengine.random import normal, uniform
 
 
 def test_trace():
@@ -431,3 +432,23 @@ def test_slice():
     y = f(x)
     np.testing.assert_array_equal(y.numpy(), x.numpy()[:, 1::2])
     y + y
+
+
+def test_random():
+    def run_test(op):
+        for symbolic_shape in [True, False]:
+
+            @trace(symbolic=True, symbolic_shape=symbolic_shape)
+            def f():
+                out = op(size=[10, 10])
+                out_shape = out.shape
+                assert out_shape is not None
+                if not isinstance(out_shape, tuple):
+                    assert out.shape.numpy() is not None
+                return out
+
+            for _ in range(3):
+                f()
+
+    run_test(uniform)
+    run_test(normal)