implement relative cimports and fix some general issues with relative imports

Cython/Compiler/Main.py

@@ -123,7 +123,7 @@ class Context(object):
                 pos = (module_name, 0, 0)
             raise CompileError(pos,
                 "'%s' is not a valid module name" % module_name)
-        if "." not in module_name and relative_to:
+        if relative_to:
             if debug_find_module:
                 print("...trying relative import")
             scope = relative_to.lookup_submodule(module_name)
@@ -139,7 +139,7 @@ class Context(object):
             for name in module_name.split("."):
                 scope = scope.find_submodule(name)
         if debug_find_module:
-            print("...scope =", scope)
+            print("...scope = %s" % scope)
         if not scope.pxd_file_loaded:
             if debug_find_module:
                 print("...pxd not loaded")
@@ -149,7 +149,7 @@ class Context(object):
                     print("...looking for pxd file")
                 pxd_pathname = self.find_pxd_file(module_name, pos)
                 if debug_find_module:
-                    print("......found ", pxd_pathname)
+                    print("......found %s" % pxd_pathname)
                 if not pxd_pathname and need_pxd:
                     package_pathname = self.search_include_directories(module_name, ".py", pos)
                     if package_pathname and package_pathname.endswith('__init__.py'):

Cython/Compiler/Nodes.py

@@ -6864,15 +6864,22 @@ class FromCImportStatNode(StatNode):
     #  from ... cimport statement
     #
     #  module_name     string                        Qualified name of module
+    #  relative_level  int or None                   Relative import: number of dots before module_name
     #  imported_names  [(pos, name, as_name, kind)]  Names to be imported
 
     child_attrs = []
+    module_name = None
+    relative_level = None
+    imported_names = None
 
     def analyse_declarations(self, env):
         if not env.is_module_scope:
             error(self.pos, "cimport only allowed at module level")
             return
-        module_scope = env.find_module(self.module_name, self.pos)
+        if self.relative_level and self.relative_level > env.qualified_name.count('.'):
+            error(self.pos, "relative cimport beyond main package is not allowed")
+        module_scope = env.find_module(self.module_name, self.pos, relative_level=self.relative_level)
+        module_name = module_scope.qualified_name
         env.add_imported_module(module_scope)
         for pos, name, as_name, kind in self.imported_names:
             if name == "*":
@@ -6886,29 +6893,27 @@ class FromCImportStatNode(StatNode):
                     entry.used = 1
                 else:
                     if kind == 'struct' or kind == 'union':
-                        entry = module_scope.declare_struct_or_union(name,
-                            kind = kind, scope = None, typedef_flag = 0, pos = pos)
+                        entry = module_scope.declare_struct_or_union(
+                            name, kind=kind, scope=None, typedef_flag=0, pos=pos)
                     elif kind == 'class':
-                        entry = module_scope.declare_c_class(name, pos = pos,
-                            module_name = self.module_name)
+                        entry = module_scope.declare_c_class(name, pos=pos, module_name=module_name)
                     else:
-                        submodule_scope = env.context.find_module(name, relative_to = module_scope, pos = self.pos)
+                        submodule_scope = env.context.find_module(name, relative_to=module_scope, pos=self.pos)
                         if submodule_scope.parent_module is module_scope:
                             env.declare_module(as_name or name, submodule_scope, self.pos)
                         else:
-                            error(pos, "Name '%s' not declared in module '%s'"
-                                % (name, self.module_name))
+                            error(pos, "Name '%s' not declared in module '%s'" % (name, module_name))
 
                 if entry:
                     local_name = as_name or name
                     env.add_imported_entry(local_name, entry, pos)
 
-        if self.module_name.startswith('cpython'): # enough for now
-            if self.module_name in utility_code_for_cimports:
+        if module_name.startswith('cpython'): # enough for now
+            if module_name in utility_code_for_cimports:
                 env.use_utility_code(UtilityCode.load_cached(
-                    *utility_code_for_cimports[self.module_name]))
+                    *utility_code_for_cimports[module_name]))
             for _, name, _, _ in self.imported_names:
-                fqname = '%s.%s' % (self.module_name, name)
+                fqname = '%s.%s' % (module_name, name)
                 if fqname in utility_code_for_cimports:
                     env.use_utility_code(UtilityCode.load_cached(
                         *utility_code_for_cimports[fqname]))
@@ -6978,8 +6983,8 @@ class FromImportStatNode(StatNode):
                         continue
                     try:
                         # cimported with relative name
-                        module = env.find_module(self.module.module_name.value,
-                                                 pos=None)
+                        module = env.find_module(self.module.module_name.value, pos=self.pos,
+                                                 relative_level=self.module.level)
                         if entry.type.module_name == module.qualified_name:
                             continue
                     except AttributeError:

Cython/Compiler/ParseTreeTransforms.py

@@ -762,8 +762,8 @@ class InterpretCompilerDirectives(CythonTransform, SkipDeclarations):
         return node
 
     def visit_FromCImportStatNode(self, node):
-        if (node.module_name == u"cython") or \
-               node.module_name.startswith(u"cython."):
+        if not node.relative_level and (
+                node.module_name == u"cython" or node.module_name.startswith(u"cython.")):
             submodule = (node.module_name + u".")[7:]
             newimp = []
 

Cython/Compiler/Parsing.py

@@ -1319,24 +1319,19 @@ def p_from_import_statement(s, first_statement = 0):
         while s.sy == '.':
             level += 1
             s.next()
-        if s.sy == 'cimport':
-            s.error("Relative cimport is not supported yet")
     else:
         level = None
-    if level is not None and s.sy == 'import':
+    if level is not None and s.sy in ('import', 'cimport'):
         # we are dealing with "from .. import foo, bar"
         dotted_name_pos, dotted_name = s.position(), ''
-    elif level is not None and s.sy == 'cimport':
-        # "from .. cimport"
-        s.error("Relative cimport is not supported yet")
     else:
-        (dotted_name_pos, _, dotted_name, _) = \
-            p_dotted_name(s, as_allowed = 0)
-    if s.sy in ('import', 'cimport'):
+        if level is None and Future.absolute_import in s.context.future_directives:
+            level = 0
+        (dotted_name_pos, _, dotted_name, _) = p_dotted_name(s, as_allowed=False)
+    if s.sy not in ('import', 'cimport'):
+        s.error("Expected 'import' or 'cimport'")
     kind = s.sy
     s.next()
-    else:
-        s.error("Expected 'import' or 'cimport'")
 
     is_cimport = kind == 'cimport'
     is_parenthesized = False
@@ -1359,7 +1354,7 @@ def p_from_import_statement(s, first_statement = 0):
     if dotted_name == '__future__':
         if not first_statement:
             s.error("from __future__ imports must occur at the beginning of the file")
-        elif level is not None:
+        elif level:
             s.error("invalid syntax")
         else:
             for (name_pos, name, as_name, kind) in imported_names:
@@ -1374,9 +1369,10 @@ def p_from_import_statement(s, first_statement = 0):
                 s.context.future_directives.add(directive)
         return Nodes.PassStatNode(pos)
     elif kind == 'cimport':
-        return Nodes.FromCImportStatNode(pos,
-            module_name = dotted_name,
-            imported_names = imported_names)
+        return Nodes.FromCImportStatNode(
+            pos, module_name=dotted_name,
+            relative_level=level,
+            imported_names=imported_names)
     else:
         imported_name_strings = []
         items = []

Cython/Compiler/Symtab.py

@@ -1081,13 +1081,19 @@ class ModuleScope(Scope):
             entry.name = name
         return entry
 
-    def find_module(self, module_name, pos):
+    def find_module(self, module_name, pos, relative_level=-1):
         # Find a module in the import namespace, interpreting
         # relative imports relative to this module's parent.
         # Finds and parses the module's .pxd file if the module
         # has not been referenced before.
-        return self.global_scope().context.find_module(
-            module_name, relative_to = self.parent_module, pos = pos)
+        module_scope = self.global_scope()
+        if relative_level is not None and relative_level > 0:
+            # merge current absolute module name and relative import name into qualified name
+            current_module = module_scope.qualified_name.split('.')
+            base_package = current_module[:-relative_level]
+            module_name = '.'.join(base_package + module_name.split('.'))
+        return module_scope.context.find_module(
+            module_name, relative_to=None if relative_level == 0 else self.parent_module, pos=pos)
 
     def find_submodule(self, name):
         # Find and return scope for a submodule of this module,

tests/errors/e_relative_cimport.pyx

+# mode: error
+# tag: cimport
+
+from ..relative_cimport cimport some_name
+
+from ..cython cimport declare
+
+
+_ERRORS="""
+4:0: 'relative_cimport.pxd' not found
+4:0: 'some_name.pxd' not found
+4:0: relative cimport beyond main package is not allowed
+4:32: Name 'some_name' not declared in module 'relative_cimport'
+6:0: 'declare.pxd' not found
+6:0: relative cimport beyond main package is not allowed
+6:22: Name 'declare' not declared in module 'cython'
+"""

tests/run/relative_cimport.srctree

+# mode: run
+# tag: cimport
+
+PYTHON setup.py build_ext --inplace
+PYTHON -c "from pkg.b import test; assert test() == (1, 2)"
+PYTHON -c "from pkg.sub.c import test; assert test() == (1, 2)"
+
+######## setup.py ########
+
+from distutils.core import setup
+from Cython.Build import cythonize
+from Cython.Distutils.extension import Extension
+
+setup(
+    ext_modules=cythonize('**/*.pyx'),
+)
+
+
+######## pkg/__init__.py ########
+
+######## pkg/sub/__init__.py ########
+
+######## pkg/a.pyx ########
+
+cdef class test_pxd:
+    pass
+
+
+######## pkg/a.pxd ########
+
+cdef class test_pxd:
+    cdef public int x
+    cdef public int y
+
+
+######## pkg/b.pyx ########
+
+from .a cimport test_pxd
+
+
+def test():
+    cdef test_pxd obj = test_pxd()
+    obj.x = 1
+    obj.y = 2
+    return (obj.x, obj.y)
+
+
+######## pkg/sub/c.pyx ########
+
+from ..a cimport test_pxd
+
+
+def test():
+    cdef test_pxd obj = test_pxd()
+    obj.x = 1
+    obj.y = 2
+    return (obj.x, obj.y)