Always use cythonized files in sdist.

.travis.yml

@@ -5,9 +5,9 @@ env:
         # These ancient versions are linked to an old libgfortran, but that version
         # isn't pinned in the package metadata
         - PYTHON_VERSION=2.7
-          PACKAGES="cython=0.17 numpy=1.10.0 matplotlib=1.5.1 nose proj4=4.9.1 scipy=0.16.0 libgfortran=1 mock futures"
+          PACKAGES="cython=0.* numpy=1.10.0 matplotlib=1.5.1 nose proj4=4.9.1 scipy=0.16.0 libgfortran=1 mock futures"
         - PYTHON_VERSION=3.5
-          PACKAGES="cython=0.23.1 numpy=1.10.0 matplotlib=1.5.1 nose proj4=4.9.1 scipy=0.16.0 libgfortran=1"
+          PACKAGES="cython=0.* numpy=1.10.0 matplotlib=1.5.1 nose proj4=4.9.1 scipy=0.16.0 libgfortran=1"
           PYTHONHASHSEED=0  # So pytest-xdist works.
         - NAME="Latest everything."
           PYTHON_VERSION=3.6

INSTALL

@@ -56,7 +56,7 @@ The recipes for these can be found at https://github.com/conda-forge/feedstocks.
 **Python** 2.7 or later (https://www.python.org/)
     Cartopy requires Python 2.7 or later.
 
-**Cython** 0.17 or later (https://pypi.python.org/pypi/Cython/)
+**Cython** 0.29 or later (https://pypi.python.org/pypi/Cython/)
 
 **NumPy** 1.10 or later (http://www.numpy.org/)
     Python package for scientific computing including a powerful N-dimensional

MANIFEST.in

@@ -9,5 +9,5 @@ include lib/cartopy/data/*
 include lib/cartopy/io/srtm.npz
 include lib/cartopy/tests/lakes_shapefile/*
 recursive-include lib *.py
-recursive-include lib *.pyx *.pxd *.h
+recursive-include lib *.pyx *.pxd *.h *.c *.cpp
 include versioneer.py

pyproject.toml

@@ -1,2 +1,2 @@
 [build-system]
-requires = ["setuptools", "wheel", "numpy>=1.10", "Cython>=0.17"]
+requires = ["setuptools", "wheel", "numpy>=1.10"]

setup.py

@@ -36,10 +36,18 @@
 import versioneer
 
 
-try:
-    from Cython.Distutils import build_ext
-except ImportError:
-    raise ImportError('Cython 0.17+ is required to install cartopy.')
+# The existence of a PKG-INFO directory is enough to tell us whether this is a
+# source installation or not (sdist).
+HERE = os.path.dirname(__file__)
+IS_SDIST = os.path.exists(os.path.join(HERE, 'PKG-INFO'))
+
+if not IS_SDIST:
+    try:
+        from Cython.Distutils import build_ext
+    except ImportError:
+        raise ImportError(
+            "Cython 0.17+ is required to install cartopy from source.")
+
 try:
     import numpy as np
 except ImportError:
@@ -52,8 +60,6 @@
 GEOS_MIN_VERSION = (3, 3, 3)
 PROJ_MIN_VERSION = (4, 9, 0)
 
-HERE = os.path.dirname(__file__)
-
 
 def file_walk_relative(top, remove=''):
     """
@@ -280,8 +286,9 @@ def find_proj_version_by_program(conda=None):
             proj_includes = proj_includes.decode()
             proj_clibs = proj_clibs.decode()
 
-        proj_includes = [proj_include[2:] if proj_include.startswith('-I') else
-                         proj_include for proj_include in proj_includes.split()]      
+        proj_includes = [
+            proj_include[2:] if proj_include.startswith('-I') else
+            proj_include for proj_include in proj_includes.split()]
 
         proj_libraries = []
         proj_library_dirs = []
@@ -321,13 +328,62 @@ def get_config_var(name):
 
 # Description
 # ===========
-
 with open(os.path.join(HERE, 'README.md'), 'r') as fh:
     description = ''.join(fh.readlines())
 
 
+extensions = [
+    Extension(
+        'cartopy.trace',
+        ['lib/cartopy/trace.pyx'],
+        include_dirs=([include_dir, './lib/cartopy', np.get_include()] +
+                      proj_includes + geos_includes),
+        libraries=proj_libraries + geos_libraries,
+        library_dirs=[library_dir] + proj_library_dirs + geos_library_dirs,
+        language='c++',
+        **extra_extension_args),
+    Extension(
+        'cartopy._crs',
+        ['lib/cartopy/_crs.pyx'],
+        include_dirs=[include_dir, np.get_include()] + proj_includes,
+        libraries=proj_libraries,
+        library_dirs=[library_dir] + proj_library_dirs,
+        **extra_extension_args),
+    # Requires proj v4.9
+    Extension(
+        'cartopy.geodesic._geodesic',
+        ['lib/cartopy/geodesic/_geodesic.pyx'],
+        include_dirs=[include_dir, np.get_include()] + proj_includes,
+        libraries=proj_libraries,
+        library_dirs=[library_dir] + proj_library_dirs,
+        **extra_extension_args),
+]
+
+
+def decythonize(extensions, **_ignore):
+    # Remove pyx sources from extensions.
+    # Note: even if there are changes to the pyx files, they will be ignored.
+    for extension in extensions:
+        sources = []
+        for sfile in extension.sources:
+            path, ext = os.path.splitext(sfile)
+            if ext in ('.pyx',):
+                if extension.language == 'c++':
+                    ext = '.cpp'
+                else:
+                    ext = '.c'
+                sfile = path + ext
+            sources.append(sfile)
+        extension.sources[:] = sources
+    return extensions
+
+
 cmdclass = versioneer.get_cmdclass()
-cmdclass.update({'build_ext': build_ext})
+
+if IS_SDIST:
+    extensions = decythonize(extensions)
+else:
+    cmdclass.update({'build_ext': build_ext})
 
 
 # Main setup
@@ -368,36 +424,7 @@ def get_config_var(name):
 
 
     # requires proj headers
-    ext_modules=[
-        Extension(
-            'cartopy.trace',
-            ['lib/cartopy/trace.pyx'],
-            include_dirs=([include_dir, './lib/cartopy', np.get_include()] +
-                          proj_includes + geos_includes),
-            libraries=proj_libraries + geos_libraries,
-            library_dirs=[library_dir] + proj_library_dirs + geos_library_dirs,
-            language='c++',
-            **extra_extension_args
-        ),
-        Extension(
-            'cartopy._crs',
-            ['lib/cartopy/_crs.pyx'],
-            include_dirs=[include_dir, np.get_include()] + proj_includes,
-            libraries=proj_libraries,
-            library_dirs=[library_dir] + proj_library_dirs,
-            **extra_extension_args
-        ),
-        # Requires proj v4.9
-        Extension(
-            'cartopy.geodesic._geodesic',
-            ['lib/cartopy/geodesic/_geodesic.pyx'],
-            include_dirs=[include_dir, np.get_include()] + proj_includes,
-            libraries=proj_libraries,
-            library_dirs=[library_dir] + proj_library_dirs,
-            **extra_extension_args
-        ),
-    ],
-
+    ext_modules=extensions,
     cmdclass=cmdclass,
     python_requires='>=2.7, !=3.0.*, !=3.1.*, !=3.2.*, !=3.3.*, !=3.4.*',
     classifiers=[