[Relay][Bug] Error raised by relay.TensorType is not handled properly

[junrushao]

Minimal reproducible example

# file: main.py
from tvm import relay
relay.TensorType((1, ), "random_illegal_string")

Stacktrace in Python3

>>> python3 main.py
Traceback (most recent call last):
  File "main.py", line 2, in <module>
    relay.TensorType((1, ), "random_illegal_string")
  File "/path/to/tvm/python/tvm/relay/ty.py", line 44, in __init__
    self.__init_handle_by_constructor__(_make.TensorType, shape, dtype)
  File "/path/to/tvm/python/tvm/_ffi/_ctypes/node.py", line 79, in __init_handle_by_constructor__
    handle = __init_by_constructor__(fconstructor, args)
  File "/path/to/tvm/python/tvm/_ffi/_ctypes/function.py", line 199, in __init_handle_by_constructor__
    ctypes.byref(ret_val), ctypes.byref(ret_tcode)))
  File "/path/to/tvm/python/tvm/_ffi/base.py", line 66, in check_call
    raise TVMError(py_str(_LIB.TVMGetLastError()))
tvm._ffi.base.TVMError: [13:30:57] /path/to/tvm/include/tvm/runtime/packed_func.h:925: unknown type random_illegal_string

Stack trace returned 10 entries:
[bt] (0) /path/to/tvm/build/libtvm.so(dmlc::StackTrace[abi:cxx11]()+0x1a9) [0x7f875dab54f9]
[bt] (1) /path/to/tvm/build/libtvm.so(dmlc::LogMessageFatal::~LogMessageFatal()+0x18) [0x7f875dab63e8]
[bt] (2) /path/to/tvm/build/libtvm.so(tvm::runtime::TVMArgValue::operator DLDataType() const+0xd4b) [0x7f875dac531b]
[bt] (3) /path/to/tvm/build/libtvm.so(+0x50969f) [0x7f875dd9569f]
[bt] (4) /path/to/tvm/build/libtvm.so(TVMFuncCall+0x48) [0x7f875df69c48]
[bt] (5) /path/to/lib/libffi.so.6(ffi_call_unix64+0x4c) [0x7f8780bcfff6]
[bt] (6) /path/to/lib/libffi.so.6(ffi_call+0x273) [0x7f8780bcfc83]
[bt] (7) /path/to/python/3.7.0/lib/python3.7/lib-dynload/_ctypes.cpython-37m-x86_64-linux-gnu.so(_ctypes_callproc+0x2cf) [0x7f8780de4c2f]
[bt] (8) /path/to/python/3.7.0/lib/python3.7/lib-dynload/_ctypes.cpython-37m-x86_64-linux-gnu.so(+0xaee3) [0x7f8780ddeee3]
[bt] (9) /path/to/lib/libpython3.7m.so.1.0(_PyObject_FastCallKeywords+0x104) [0x7f878153e504]

Exception ignored in: <function NodeBase.__del__ at 0x7f875e141a60>
Traceback (most recent call last):
  File "/path/to/tvm/python/tvm/_ffi/_ctypes/node.py", line 46, in __del__
    check_call(_LIB.TVMNodeFree(self.handle))
  File "/path/to/tvm/python/tvm/_ffi/_ctypes/node.py", line 53, in __getattr__
    self.handle, c_str(name),
  File "/path/to/tvm/python/tvm/_ffi/_ctypes/node.py", line 53, in __getattr__
    self.handle, c_str(name),
  File "/path/to/tvm/python/tvm/_ffi/_ctypes/node.py", line 53, in __getattr__
    self.handle, c_str(name),
  [Previous line repeated 495 more times]
RecursionError: maximum recursion depth exceeded

Stacktrace in Python2

>>> python2.7 main.py
Traceback (most recent call last):
  File "main.py", line 2, in <module>
    relay.TensorType((1, ), "random_illegal_string")
  File "/path/to/tvm/python/tvm/relay/ty.py", line 44, in __init__
    self.__init_handle_by_constructor__(_make.TensorType, shape, dtype)
  File "/path/to/tvm/python/tvm/_ffi/_ctypes/node.py", line 79, in __init_handle_by_constructor__
    handle = __init_by_constructor__(fconstructor, args)
  File "/path/to/tvm/python/tvm/_ffi/_ctypes/function.py", line 199, in __init_handle_by_constructor__
    ctypes.byref(ret_val), ctypes.byref(ret_tcode)))
  File "/path/to/tvm/python/tvm/_ffi/base.py", line 66, in check_call
    raise TVMError(py_str(_LIB.TVMGetLastError()))
tvm._ffi.base.TVMError: [13:30:35] /path/to/tvm/include/tvm/runtime/packed_func.h:925: unknown type random_illegal_string

Stack trace returned 10 entries:
[bt] (0) /path/to/tvm/build/libtvm.so(dmlc::StackTrace[abi:cxx11]()+0x1a9) [0x7f77b981f4f9]
[bt] (1) /path/to/tvm/build/libtvm.so(dmlc::LogMessageFatal::~LogMessageFatal()+0x18) [0x7f77b98203e8]
[bt] (2) /path/to/tvm/build/libtvm.so(tvm::runtime::TVMArgValue::operator DLDataType() const+0xd4b) [0x7f77b982f31b]
[bt] (3) /path/to/tvm/build/libtvm.so(+0x50969f) [0x7f77b9aff69f]
[bt] (4) /path/to/tvm/build/libtvm.so(TVMFuncCall+0x48) [0x7f77b9cd3c48]
[bt] (5) /path/to/python@2/2.7.15_1/lib/python2.7/lib-dynload/_ctypes.so(ffi_call_unix64+0x4c) [0x7f77dc65f974]
[bt] (6) /path/to/python@2/2.7.15_1/lib/python2.7/lib-dynload/_ctypes.so(ffi_call+0x2ba) [0x7f77dc65f46a]
[bt] (7) /path/to/python@2/2.7.15_1/lib/python2.7/lib-dynload/_ctypes.so(_ctypes_callproc+0x2cf) [0x7f77dc6585af]
[bt] (8) /path/to/python@2/2.7.15_1/lib/python2.7/lib-dynload/_ctypes.so(+0xc374) [0x7f77dc652374]
[bt] (9) /path/to/lib/libpython2.7.so.1.0(PyObject_Call+0x43) [0x7f77dccb1dc3]

Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
Exception RuntimeError: 'maximum recursion depth exceeded while calling a Python object' in <object repr() failed> ignored
^C

[tqchen]

should be fixed by #1850

[junrushao]

Will close once #1850 is merged.