provide compiler directive to set __file__ and __path__ from the source path at module init time

Cython/Compiler/ModuleNode.py

@@ -22,7 +22,7 @@ import PyrexTypes
 
 from Errors import error, warning
 from PyrexTypes import py_object_type
-from Cython.Utils import open_new_file, replace_suffix
+from Cython.Utils import open_new_file, replace_suffix, decode_filename
 from Code import UtilityCode
 from StringEncoding import EncodedString
 
@@ -1829,6 +1829,28 @@ class ModuleNode(Nodes.Node, Nodes.BlockNode):
                 code.error_goto(self.pos)))
         code.putln("}")
 
+        if env.directives['set_initial_path_from_source'] and self.pos[0]:
+            source_path = self.pos[0].filename
+            if source_path:
+                code.putln('if (__Pyx_SetAttrString(%s, "__file__", %s) < 0) %s;' % (
+                    env.module_cname,
+                    code.globalstate.get_py_string_const(
+                        EncodedString(decode_filename(source_path))).cname,
+                code.error_goto(self.pos)))
+                if os.path.splitext(os.path.basename(source_path))[0] == '__init__':
+                    # compiling a package => set __path__ as well
+                    temp = code.funcstate.allocate_temp(py_object_type, True)
+                    code.putln('%s = Py_BuildValue("[O]", %s); %s' % (
+                        temp,
+                        code.globalstate.get_py_string_const(
+                            EncodedString(decode_filename(os.path.dirname(source_path)))).cname,
+                        code.error_goto_if_null(temp, self.pos)))
+                    code.putln('if (__Pyx_SetAttrString(%s, "__path__", %s) < 0) %s;' % (
+                        env.module_cname,
+                        temp,
+                        code.error_goto(self.pos)))
+                    code.funcstate.release_temp(temp)
+
         if Options.cache_builtins:
             code.putln("/*--- Builtin init code ---*/")
             code.putln(code.error_goto_if_neg("__Pyx_InitCachedBuiltins()", self.pos))

Cython/Compiler/Options.py

@@ -98,6 +98,9 @@ directive_defaults = {
     'fast_getattr': False, # Undocumented until we come up with a better way to handle this everywhere.
     'py2_import': False, # For backward compatibility of Cython's source code in Py3 source mode
 
+    # set __file__ and/or __path__ to source file path at import time (instead of not having them available)
+    'set_initial_path_from_source' : False,
+
     'warn': None,
     'warn.undeclared': False,
     'warn.unreachable': True,
@@ -153,6 +156,7 @@ directive_scopes = { # defaults to available everywhere
     'autotestdict' : ('module',),
     'autotestdict.all' : ('module',),
     'autotestdict.cdef' : ('module',),
+    'set_initial_path_from_source' : ('module',),
     'test_assert_path_exists' : ('function', 'class', 'cclass'),
     'test_fail_if_path_exists' : ('function', 'class', 'cclass'),
 }

Cython/Compiler/Symtab.py

@@ -991,7 +991,7 @@ class ModuleScope(Scope):
         self.cached_builtins = []
         self.undeclared_cached_builtins = []
         self.namespace_cname = self.module_cname
-        for var_name in ['__builtins__', '__name__', '__file__', '__doc__']:
+        for var_name in ['__builtins__', '__name__', '__file__', '__doc__', '__path__']:
             self.declare_var(EncodedString(var_name), py_object_type, None)
 
     def qualifying_scope(self):

tests/run/initial_file_path.srctree

+PYTHON setup.py build_ext --inplace
+PYTHON -c "import my_test_package, my_test_package.a; my_test_package.test(); my_test_package.a.test()"
+
+######## setup.py ########
+
+from Cython.Build.Dependencies import cythonize
+from distutils.core import setup
+
+setup(
+    ext_modules = cythonize("my_test_package/*.py"),
+)
+
+######## my_test_package/__init__.py ########
+
+# cython: set_initial_path_from_source=True
+
+initial_path = __path__
+initial_file = __file__
+
+import a
+
+def test():
+    assert initial_path[0].endswith('my_test_package'), initial_path
+    assert initial_file.endswith('__init__.py'), initial_file
+
+######## my_test_package/a.py ########
+
+# cython: set_initial_path_from_source=True
+
+initial_file = __file__
+
+try:
+    initial_path = __path__
+except NameError:
+    got_name_error = True
+else:
+    got_name_error = False
+
+def test():
+    assert initial_file.endswith('a.py'), initial_file
+    assert got_name_error, "looks like __path__ was set at module init time: " + initial_path