prevent fallback to absolute cimport when relative cimport is not found;...

prevent fallback to absolute cimport when relative cimport is not found; generally clean up relative cimport code

Cython/Compiler/Main.py

@@ -110,7 +110,8 @@ class Context(object):
     def nonfatal_error(self, exc):
         return Errors.report_error(exc)
 
-    def find_module(self, module_name, relative_to=None, pos=None, need_pxd=1, check_module_name=True):
+    def find_module(self, module_name, relative_to=None, pos=None, need_pxd=1,
+                    check_module_name=True, absolute_fallback=True):
         # Finds and returns the module scope corresponding to
         # the given relative or absolute module name. If this
         # is the first time the module has been requested, finds
@@ -125,25 +126,39 @@ class Context(object):
 
         scope = None
         pxd_pathname = None
-        if check_module_name and not module_name_pattern.match(module_name):
-            if pos is None:
-                pos = (module_name, 0, 0)
-            raise CompileError(pos, "'%s' is not a valid module name" % module_name)
+        if relative_to:
+            if module_name:
+                # from .module import ...
+                qualified_name = relative_to.qualify_name(module_name)
+            else:
+                # from . import ...
+                qualified_name = relative_to.qualified_name
+                scope = relative_to
+                relative_to = None
+        else:
+            qualified_name = module_name
+
+        if check_module_name and not module_name_pattern.match(qualified_name):
+            raise CompileError(pos or (module_name, 0, 0),
+                               "'%s' is not a valid module name" % module_name)
+
         if relative_to:
             if debug_find_module:
                 print("...trying relative import")
             scope = relative_to.lookup_submodule(module_name)
             if not scope:
-                qualified_name = relative_to.qualify_name(module_name)
                 pxd_pathname = self.find_pxd_file(qualified_name, pos)
                 if pxd_pathname:
                     scope = relative_to.find_submodule(module_name)
         if not scope:
             if debug_find_module:
                 print("...trying absolute import")
+            if absolute_fallback:
+                qualified_name = module_name
             scope = self
-            for name in module_name.split("."):
+            for name in qualified_name.split("."):
                 scope = scope.find_submodule(name)
+
         if debug_find_module:
             print("...scope = %s" % scope)
         if not scope.pxd_file_loaded:
@@ -153,15 +168,15 @@ class Context(object):
             if not pxd_pathname:
                 if debug_find_module:
                     print("...looking for pxd file")
-                pxd_pathname = self.find_pxd_file(module_name, pos)
+                pxd_pathname = self.find_pxd_file(qualified_name, pos)
                 if debug_find_module:
                     print("......found %s" % pxd_pathname)
                 if not pxd_pathname and need_pxd:
-                    package_pathname = self.search_include_directories(module_name, ".py", pos)
+                    package_pathname = self.search_include_directories(qualified_name, ".py", pos)
                     if package_pathname and package_pathname.endswith('__init__.py'):
                         pass
                     else:
-                        error(pos, "'%s.pxd' not found" % module_name.replace('.', os.sep))
+                        error(pos, "'%s.pxd' not found" % qualified_name.replace('.', os.sep))
             if pxd_pathname:
                 try:
                     if debug_find_module:
@@ -170,7 +185,7 @@ class Context(object):
                     if not pxd_pathname.endswith(rel_path):
                         rel_path = pxd_pathname  # safety measure to prevent printing incorrect paths
                     source_desc = FileSourceDescriptor(pxd_pathname, rel_path)
-                    err, result = self.process_pxd(source_desc, scope, module_name)
+                    err, result = self.process_pxd(source_desc, scope, qualified_name)
                     if err:
                         raise err
                     (pxd_codenodes, pxd_scope) = result

Cython/Compiler/Nodes.py

@@ -7224,6 +7224,7 @@ class FromCImportStatNode(StatNode):
             return
         if self.relative_level and self.relative_level > env.qualified_name.count('.'):
             error(self.pos, "relative cimport beyond main package is not allowed")
+            return
         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)
@@ -7244,7 +7245,8 @@ class FromCImportStatNode(StatNode):
                     elif kind == 'class':
                         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, absolute_fallback=False)
                         if submodule_scope.parent_module is module_scope:
                             env.declare_module(as_name or name, submodule_scope, self.pos)
                         else:

Cython/Compiler/Symtab.py

@@ -1127,14 +1127,20 @@ class ModuleScope(Scope):
         # relative imports relative to this module's parent.
         # Finds and parses the module's .pxd file if the module
         # has not been referenced before.
-        module_scope = self.global_scope()
+        relative_to = None
         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('.') if module_name else []))
+            absolute_fallback = False
+            # error of going beyond top-level is handled in cimport node
+            relative_to = self
+            while relative_level > 0 and relative_to:
+                relative_to = relative_to.parent_module
+                relative_level -= 1
+        else:
+            absolute_fallback = relative_level != 0  # might be None!
+
+        module_scope = self.global_scope()
         return module_scope.context.find_module(
-            module_name, relative_to=None if relative_level == 0 else self.parent_module, pos=pos)
+            module_name, relative_to=relative_to, pos=pos, absolute_fallback=absolute_fallback)
 
     def find_submodule(self, name):
         # Find and return scope for a submodule of this module,

Cython/Compiler/UtilityCode.py

@@ -34,7 +34,9 @@ class NonManglingModuleScope(Symtab.ModuleScope):
 class CythonUtilityCodeContext(StringParseContext):
     scope = None
 
-    def find_module(self, module_name, relative_to=None, pos=None, need_pxd=True):
+    def find_module(self, module_name, relative_to=None, pos=None, need_pxd=True, absolute_fallback=True):
+        if relative_to:
+            raise AssertionError("Relative imports not supported in utility code.")
         if module_name != self.module_name:
             if module_name not in self.modules:
                 raise AssertionError("Only the cython cimport is supported.")

tests/errors/e_relative_cimport.pyx

@@ -2,16 +2,14 @@
 # tag: cimport
 
 from ..relative_cimport cimport some_name
-
+from .e_relative_cimport cimport some_name
 from ..cython cimport declare
+from . cimport e_relative_cimport
 
 
 _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
+5:0: relative cimport beyond main package is not allowed
 6:0: relative cimport beyond main package is not allowed
-6:22: Name 'declare' not declared in module 'cython'
+7:0: relative cimport beyond main package is not allowed
 """