From ba5e2645bf9dd706fc0296b0cf7aeff1b42a660c Mon Sep 17 00:00:00 2001
From: Jason Madden <jamadden@gmail.com>
Date: Tue, 16 Oct 2018 09:01:39 -0500
Subject: [PATCH] Build with Cython 0.29 using '3str' as the language level.

Fixes #94
---
 CHANGES.rst      |  2 +-
 requirements.txt |  2 +-
 setup.py         | 59 ++++++++++++++++++++++++++++++------------------
 tox.ini          |  2 +-
 4 files changed, 40 insertions(+), 25 deletions(-)

diff --git a/CHANGES.rst b/CHANGES.rst
index 8493d02..6d532ad 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -6,7 +6,7 @@
 1.0.0a14 (unreleased)
 =====================
 
-- Nothing changed yet.
+- Build with Cython 0.29 using '3str' as the language level.
 
 
 1.0.0a13 (2018-09-20)
diff --git a/requirements.txt b/requirements.txt
index f1fc108..5140e27 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,2 @@
-cython >= 0.28.4
+cython >= 0.29
 .[test,docs,benchmarks]
diff --git a/setup.py b/setup.py
index dee8258..d454b18 100755
--- a/setup.py
+++ b/setup.py
@@ -31,24 +31,26 @@ def _read(fname):
 
 # Cython
 
+# Based on code from
+# http://cython.readthedocs.io/en/latest/src/reference/compilation.html#distributing-cython-modules
+def _dummy_cythonize(extensions, **_kwargs):
+    for extension in extensions:
+        sources = []
+        for sfile in extension.sources:
+            path, ext = os.path.splitext(sfile)
+            if ext in ('.pyx', '.py'):
+                ext = '.c'
+                sfile = path + ext
+            sources.append(sfile)
+        extension.sources[:] = sources
+    return extensions
+
 try:
     from Cython.Build import cythonize
 except ImportError:
     # The .c files had better already exist, as they should in
-    # an sdist. Based on code from
-    # http://cython.readthedocs.io/en/latest/src/reference/compilation.html#distributing-cython-modules
-    def cythonize(extensions, **_kwargs):
-        for extension in extensions:
-            sources = []
-            for sfile in extension.sources:
-                path, ext = os.path.splitext(sfile)
-                if ext in ('.pyx', '.py'):
-                    ext = '.c'
-                    sfile = path + ext
-                sources.append(sfile)
-            extension.sources[:] = sources
-        return extensions
-
+    # an sdist.
+    cythonize = _dummy_cythonize
 
 ext_modules = []
 
@@ -119,14 +121,27 @@ def _c(m):
                 define_macros=[('CYTHON_TRACE', '1')],
             ))
 
-    ext_modules = cythonize(
-        ext_modules,
-        annotate=True,
-        compiler_directives={
-            #'linetrace': True,
-            'infer_types': True,
-        },
-    )
+    try:
+        ext_modules = cythonize(
+            ext_modules,
+            annotate=True,
+            compiler_directives={
+                #'linetrace': True,
+                'infer_types': True,
+                'language_level': '3str',
+                'always_allow_keywords': False,
+                'nonecheck': False,
+            },
+        )
+    except ValueError:
+        # 'invalid literal for int() with base 10: '3str'
+        # This is seen when an older version of Cython is installed.
+        # It's a bit of a chicken-and-egg, though, because installing
+        # from dev-requirements first scans this egg for its requirements
+        # before doing any updates.
+        import traceback
+        traceback.print_exc()
+        ext_modules = _dummy_cythonize(ext_modules)
 
 setup(
     name='nti.externalization',
diff --git a/tox.ini b/tox.ini
index abe7b08..fde1eac 100644
--- a/tox.ini
+++ b/tox.ini
@@ -6,7 +6,7 @@ envlist =
 commands =
     zope-testrunner --test-path=src []
 deps =
-     Cython >= 0.28.4
+     Cython >= 0.29
     .[test]
 
 [testenv:py27-pure]