cython: Add an option for selecting python 3 vs python 2 output

mesonbuild/backend/ninjabackend.py

@@ -1559,10 +1559,21 @@ int dummy;
 
         cython = target.compilers['cython']
 
+        opt_proxy = self.get_compiler_options_for_target(target)
+
+        args: T.List[str] = []
+        args += cython.get_always_args()
+        args += cython.get_buildtype_args(self.get_option_for_target(OptionKey('buildtype'), target))
+        args += cython.get_debug_args(self.get_option_for_target(OptionKey('debug'), target))
+        args += cython.get_optimization_args(self.get_option_for_target(OptionKey('optimization'), target))
+        args += cython.get_option_compile_args(opt_proxy)
+        args += self.build.get_global_args(cython, target.for_machine)
+        args += self.build.get_project_args(cython, target.subproject, target.for_machine)
+
         for src in target.get_sources():
             if src.endswith('.pyx'):
                 output = os.path.join(self.get_target_private_dir(target), f'{src}.c')
-                args = cython.get_always_args()
+                args = args.copy()
                 args += cython.get_output_args(output)
                 element = NinjaBuildElement(
                     self.all_outputs, [output],
@@ -1580,8 +1591,8 @@ int dummy;
                 if isinstance(gen, GeneratedList):
                     ssrc = os.path.join(self.get_target_private_dir(target) , ssrc)
                 if ssrc.endswith('.pyx'):
+                    args = args.copy()
                     output = os.path.join(self.get_target_private_dir(target), f'{ssrc}.c')
-                    args = cython.get_always_args()
                     args += cython.get_output_args(output)
                     element = NinjaBuildElement(
                         self.all_outputs, [output],

mesonbuild/compilers/cython.py

@@ -5,10 +5,12 @@
 
 import typing as T
 
-from ..mesonlib import EnvironmentException
+from .. import coredata
+from ..mesonlib import EnvironmentException, OptionKey
 from .compilers import Compiler
 
 if T.TYPE_CHECKING:
+    from ..coredata import KeyedOptionDictType
     from ..environment import Environment
 
 
@@ -24,8 +26,7 @@ class CythonCompiler(Compiler):
         return False
 
     def get_always_args(self) -> T.List[str]:
-        # XXX: we need an option to control this?
-        return ['--fast-fail', '-3']
+        return ['--fast-fail']
 
     def get_werror_args(self) -> T.List[str]:
         return ['-Werror']
@@ -59,3 +60,20 @@ class CythonCompiler(Compiler):
             new.append(i)
 
         return new
+
+    def get_options(self) -> 'KeyedOptionDictType':
+        opts = super().get_options()
+        opts.update({
+            OptionKey('version', machine=self.for_machine, lang=self.language): coredata.UserComboOption(
+                'Python version to target',
+                ['2', '3'],
+                '3',
+            )
+        })
+        return opts
+
+    def get_option_compile_args(self, options: 'KeyedOptionDictType') -> T.List[str]:
+        args: T.List[str] = []
+        key = options[OptionKey('version', machine=self.for_machine, lang=self.language)]
+        args.append(f'-{key.value}')
+        return args