Coverage >= 5 cannot handle Cython public or readonly members in .pxd file · Issue #972 · nedbat/coveragepy (original) (raw)

Describe the bug
After upgrading to coverage >= 5,
coverage run outputs this error message for a Cython pxd file with certain conditions I describe below:

Can't add file tracer data for unmeasured file '/home/kai/tst/cy/kai.pxd'

Then coverage report fails with this error:

Couldn't parse '/home/kai/tst/cy/kai.pyx' as Python source: 'invalid syntax' at line 1

To Reproduce

1. What version of coverage.py are you using? The output of coverage debug sys is helpful.

-- sys -------------------------------------------------------
                        version: 5.1
                       coverage: /home/kai/tst/lib64/python3.7/site-packages/coverage/__init__.py
                         tracer: -none-
                        CTracer: available
           plugins.file_tracers: Cython.Coverage.Plugin
            plugins.configurers: -none-
      plugins.context_switchers: -none-
              configs_attempted: .coveragerc
                                 setup.cfg
                   configs_read: /home/kai/tst/setup.cfg
                    config_file: /home/kai/tst/setup.cfg
                config_contents: '[coverage:run]\n# http://blog.behnel.de/posts/coverage-analysis-for-cython-modules.html\nplugins = Cython.Coverage\n'
                      data_file: -none-
                         python: 3.7.6 (default, Feb 26 2020, 20:54:15) [GCC 7.3.1 20180712 (Red Hat 7.3.1-6)]
                       platform: Linux-4.19.76-linuxkit-x86_64-with-glibc2.2.5
                 implementation: CPython
                     executable: /home/kai/tst/bin/python3
                   def_encoding: utf-8
                    fs_encoding: utf-8
                            pid: 9474
                            cwd: /home/kai/tst
                           path: /home/kai/tst/bin
                                 /usr/lib64/python37.zip
                                 /usr/lib64/python3.7
                                 /usr/lib64/python3.7/lib-dynload
                                 /home/kai/tst/lib64/python3.7/site-packages
                                 /home/kai/tst/lib/python3.7/site-packages
                    environment: -none-
                   command_line: /home/kai/tst/bin/coverage debug sys
                sqlite3_version: 2.6.0
         sqlite3_sqlite_version: 3.7.17
             sqlite3_temp_store: 0
        sqlite3_compile_options: DISABLE_DIRSYNC
                                 ENABLE_COLUMN_METADATA
                                 ENABLE_FTS3
                                 ENABLE_RTREE
                                 ENABLE_UNLOCK_NOTIFY
                                 SECURE_DELETE
                                 TEMP_STORE=1
                                 THREADSAFE=1

1. What versions of what packages do you have installed? The output of pip freeze is helpful.

coverage==5.1
Cython==0.29.16

Tested with coverage 4.5.4 (OK), 5.0.4 (fail), 5.1 (fail)

1. What code are you running? Give us a specific commit of a specific repo that we can check out.
   cy/__init__.pxd (empty file)

cy/kai.pxd

cdef class Kai:
    cdef readonly bint x

    cpdef bint get_x(self)

cy/kai.pyx

cdef class Kai:
    def __init__(self):
        self.x = False

    cpdef bint get_x(self):
        return self.x

cy/setup.py

from Cython.Build import cythonize
from distutils.core import setup
from distutils.extension import Extension

define_macros = [('CYTHON_TRACE', '1')]

compiler_directives = {'always_allow_keywords': True, 'profile': True, 'linetrace': True}
extensions = [
    Extension('cy.kai', ['cy/kai.pyx'], define_macros=define_macros),
    ]
setup(ext_modules=cythonize(extensions, nthreads=4, annotate=True, language_level="3", compiler_directives=compiler_directives))

runner.py

from cy import kai

k = kai.Kai()
print(k.get_x())
print(k.x)

1. What commands did you run?

$ python3 cy/setup.py build_ext --inplace
$ coverage run runner.py
$ coverage report

Expected behavior
Coverage statistics for pyx and pxd files

Additional context
The problem manifests itself only when

1. coverage >= 5
2. public or readonly members are in .pxd file, separate from .pyx file, and
3. runner.py actually accesses the members directly

My understanding is readonly and public modifiers make Cython define wrapper functions for them transparently. coverage >= 5 seem to play badly with them.