Compiler crash with cython.view.array: 'NoneType' object has no attribute 'lookup'

[mdickinson]

Since Cython 0.24, I'm seeing a compilation failure on code that's using cython.view.array to dynamically create typed memoryviews. Here's the end of the traceback I get (full code to reproduce and full traceback are at the end of this report):

Compiler crash traceback from this point on:
  File "/Users/mdickinson/.edm/envs/test/lib/python2.7/site-packages/Cython/Compiler/ExprNodes.py", line 1783, in compile_time_value
    return denv.lookup(self.name)
AttributeError: 'NoneType' object has no attribute 'lookup'

The failure seems very similar to that reported in April 2016 on the cython-devel mailing list, in a message entitled "Cython compiler crash in 0.24": https://mail.python.org/pipermail/cython-devel/2016-April/004771.html

Versions in use: Cython 0.25.2-1, Python 2.7.12, OS X 10.9.5.

---

Here's a cut-down version of the original code (and yes, the original code made more sense than this):

(test)bash-3.2$ cat view_array_compile_failure.pyx 
cimport cython
cimport numpy as np
import numpy as np

cdef double _safe_interp(
        double x,
        double[::1] xp,
        double[::1] fp,
        size_t n,
    ):
    return 1.3

def convert(object depth_to_time):
    sample_count = 16

    native_trace = cython.view.array(
        shape=(sample_count,),
        itemsize=sizeof(double),
        format='d',
    )

    return np.zeros(16, dtype=np.float64)

Under Cython < 0.24, this compiles without error. Under Cython 0.24 and later, I get a traceback like the following:

(test)bash-3.2$ cythonize view_array_compile_failure.pyx 
Compiling /Users/mdickinson/Desktop/view_array_compile_failure.pyx because it changed.
[1/1] Cythonizing /Users/mdickinson/Desktop/view_array_compile_failure.pyx

Error compiling Cython file:
------------------------------------------------------------
...

def convert(object depth_to_time):
    sample_count = 16

    native_trace = cython.view.array(
        shape=(sample_count,),
                          ^
------------------------------------------------------------

view_array_compile_failure.pyx:17:27: Compiler crash in TransformBuiltinMethods

ModuleNode.body = StatListNode(view_array_compile_failure.pyx:1:0)
StatListNode.stats[4] = StatListNode(view_array_compile_failure.pyx:13:0)
StatListNode.stats[0] = DefNode(view_array_compile_failure.pyx:13:0,
    modifiers = [...]/0,
    name = u'convert',
    num_required_args = 1,
    py_wrapper_required = True,
    reqd_kw_flags_cname = '0')
DefNode.body = StatListNode(view_array_compile_failure.pyx:14:4,
    is_terminator = True)
StatListNode.stats[1] = SingleAssignmentNode(view_array_compile_failure.pyx:16:36)
SingleAssignmentNode.rhs = GeneralCallNode(view_array_compile_failure.pyx:16:36,
    result_is_used = True,
    use_managed_ref = True)
File 'ExprNodes.py', line 8158, in compile_time_value: DictNode(view_array_compile_failure.pyx:17:13,
    is_dict_literal = True,
    is_temp = 1,
    obj_conversion_errors = [...]/0,
    reject_duplicates = True,
    result_is_used = True,
    use_managed_ref = True)
File 'ExprNodes.py', line 7457, in compile_time_value: TupleNode(view_array_compile_failure.pyx:17:15,
    is_sequence_constructor = 1,
    result_is_used = True,
    use_managed_ref = True)
File 'ExprNodes.py', line 6853, in compile_time_value_list: TupleNode(view_array_compile_failure.pyx:17:15,
    is_sequence_constructor = 1,
    result_is_used = True,
    use_managed_ref = True)
File 'ExprNodes.py', line 1785, in compile_time_value: NameNode(view_array_compile_failure.pyx:17:27,
    cf_maybe_null = True,
    is_name = True,
    name = u'sample_count',
    result_is_used = True,
    use_managed_ref = True)

Compiler crash traceback from this point on:
  File "/Users/mdickinson/.edm/envs/test/lib/python2.7/site-packages/Cython/Compiler/ExprNodes.py", line 1783, in compile_time_value
    return denv.lookup(self.name)
AttributeError: 'NoneType' object has no attribute 'lookup'
Traceback (most recent call last):
  File "/Users/mdickinson/.edm/envs/test/bin/cythonize", line 10, in <module>
    sys.exit(main())
  File "/Users/mdickinson/.edm/envs/test/lib/python2.7/site-packages/Cython/Build/Cythonize.py", line 196, in main
    cython_compile(path, options)
  File "/Users/mdickinson/.edm/envs/test/lib/python2.7/site-packages/Cython/Build/Cythonize.py", line 90, in cython_compile
    **options.options)
  File "/Users/mdickinson/.edm/envs/test/lib/python2.7/site-packages/Cython/Build/Dependencies.py", line 934, in cythonize
    cythonize_one(*args)
  File "/Users/mdickinson/.edm/envs/test/lib/python2.7/site-packages/Cython/Build/Dependencies.py", line 1056, in cythonize_one
    raise CompileError(None, pyx_file)
Cython.Compiler.Errors.CompileError: /Users/mdickinson/Desktop/view_array_compile_failure.pyx

[mdickinson]

Still an issue with Cython 0.26. Is there any other information I can provide to help move this forward?

[scoder]

Thank you for your very detailed report and sorry it took us so long to fix the issue.