Add partial shape inference for values that are used as shapes.

With this change, the shape inference for `tf.reshape()` will
correctly observe that, for example:

```python
x = tf.placeholder(tf.float32)
y = tf.placeholder(tf.int32)
z = tf.reshape(x, [y, 37])
print(z.get_shape())  # ==> (?, 37)
```

Partially addresses #2938.
Change: 125875146

1 files changed, 14 insertions, 5 deletions

diff --git a/tensorflow/python/kernel_tests/reshape_op_test.py b/tensorflow/python/kernel_tests/reshape_op_test.py
index 0487621b46..a68f722244 100644
--- a/tensorflow/python/kernel_tests/reshape_op_test.py
+++ b/tensorflow/python/kernel_tests/reshape_op_test.py
@@ -99,11 +99,6 @@ class ReshapeTest(tf.test.TestCase):
     self._testBothReshape(x, [1, -1, 5])
 
   def testErrors(self):
-    x = tf.constant(0.0, shape=[1, 0, 3])
-    with self.assertRaisesRegexp(
-        ValueError, "cannot infer the missing input size"):
-      tf.reshape(x, [0, -1, 5])
-
     y = tf.constant(0.0, shape=[23, 29, 31])
     with self.assertRaisesRegexp(ValueError, "isn't divisible by 17"):
       tf.reshape(y, [17, -1])
@@ -128,6 +123,20 @@ class ReshapeTest(tf.test.TestCase):
     y = tf.reshape(x, tf.placeholder(tf.int32, shape=(3,)))
     self.assertEqual([None, None, None], y.get_shape().as_list())
 
+    # Unknown input shape, partial new shape using `tf.pack()`.
+    y = tf.reshape(x, [tf.placeholder(tf.int32), 37])
+    self.assertEqual([None, 37], y.get_shape().as_list())
+
+    # Unknown input shape, partial new shape using `tf.concat()`.
+    y = tf.reshape(x, tf.concat(0, [tf.placeholder(tf.int32, shape=(2,)),
+                                    [37, 42]]))
+    self.assertEqual([None, None, 37, 42], y.get_shape().as_list())
+
+    # Unknown input shape, partial new shape using `tf.shape()`.
+    y = tf.reshape(x, tf.shape(tf.placeholder(tf.float32,
+                                              shape=[None, 37, None])))
+    self.assertEqual([None, 37, None], y.get_shape().as_list())
+
 
 if __name__ == "__main__":
   tf.test.main()