MAINT,BUG: Fix mtrand for Cython 0.27.

The `import_array()` macro, that defined a C code block that included a
return, was not handled correctly. The fix here is to cdef a replacement
`import_array` function with a defined error return. The new function is
a slight variation of the corresponding function defined by Cython.

2 files changed, 12 insertions, 2 deletions

diff --git a/numpy/random/mtrand/numpy.pxd b/numpy/random/mtrand/numpy.pxd
index 32b19c1ab..db6265238 100644
--- a/numpy/random/mtrand/numpy.pxd
+++ b/numpy/random/mtrand/numpy.pxd
@@ -1,4 +1,5 @@
 # :Author:    Travis Oliphant
+from cpython.exc cimport PyErr_Print
 
 cdef extern from "numpy/npy_no_deprecated_api.h": pass
 
@@ -134,7 +135,7 @@ cdef extern from "numpy/arrayobject.h":
 
     dtype PyArray_DescrFromType(int)
 
-    void import_array()
+    int _import_array() except -1
 
 # include functions that were once macros in the new api
 
@@ -151,3 +152,12 @@ cdef extern from "numpy/arrayobject.h":
     int PyArray_TYPE(ndarray arr)
     int PyArray_CHKFLAGS(ndarray arr, int flags)
     object PyArray_GETITEM(ndarray arr, char *itemptr)
+
+
+# copied from cython version with addition of PyErr_Print.
+cdef inline int import_array() except -1:
+    try:
+        _import_array()
+    except Exception:
+        PyErr_Print()
+        raise ImportError("numpy.core.multiarray failed to import")
diff --git a/tools/travis-before-install.sh b/tools/travis-before-install.sh
index 3203658d5..5e5278ce5 100755
--- a/tools/travis-before-install.sh
+++ b/tools/travis-before-install.sh
@@ -26,6 +26,6 @@ fi
 source venv/bin/activate
 python -V
 pip install --upgrade pip setuptools
-pip install nose pytz cython==0.26
+pip install nose pytz cython
 if [ -n "$USE_ASV" ]; then pip install asv; fi
 popd