Add two new exceptions, AstroidImportError and AstroidSyntaxError.

They are subclasses of AstroidBuildingException and are raised when
a module can't be imported from various reasons.
Also do_import_module lets the errors to bubble up without converting
them to InferenceError. This particular conversion happens only
during the inference.

9 files changed, 63 insertions, 49 deletions

diff --git a/ChangeLog b/ChangeLog
index 5e2b17b..5003418 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,14 @@
 Change log for the astroid package (used to be astng)
 =====================================================
 
+--
+
+    * Add two new exceptions, AstroidImportError and AstroidSyntaxError.
+      They are subclasses of AstroidBuildingException and are raised when
+      a module can't be imported from various reasons.
+      Also do_import_module lets the errors to bubble up without converting
+      them to InferenceError. This particular conversion happens only
+      during the inference.
 
     * Revert to using printf-style formatting in as_string, in order
       to avoid a potential problem with encodings when using .format.
diff --git a/astroid/builder.py b/astroid/builder.py
index 9e06ef7..089cdd0 100644
--- a/astroid/builder.py
+++ b/astroid/builder.py
@@ -47,13 +47,7 @@ if sys.version_info >= (3, 0):
         with open(filename, 'rb') as byte_stream:
             encoding = detect_encoding(byte_stream.readline)[0]
         stream = open(filename, 'r', newline=None, encoding=encoding)
-        try:
-            data = stream.read()
-        except UnicodeError:  # wrong encoding
-            # detect_encoding returns utf-8 if no encoding specified
-            util.reraise(exceptions.AstroidBuildingException(
-                'Wrong ({encoding}) or no encoding specified for {filename}.',
-                encoding=encoding, filename=filename))
+        data = stream.read()
         return stream, encoding, data
 
 else:
@@ -128,9 +122,14 @@ class AstroidBuilder(raw_building.InspectBuilder):
                 'Unable to load file {path}:\n{error}',
                 modname=modname, path=path, error=exc))
         except (SyntaxError, LookupError) as exc:
-            util.reraise(exceptions.AstroidBuildingException(
+            util.reraise(exceptions.AstroidSyntaxError(
                 'Python 3 encoding specification error or unknown encoding:\n'
                 '{error}', modname=modname, path=path, error=exc))
+        except UnicodeError:  # wrong encoding
+            # detect_encoding returns utf-8 if no encoding specified
+            util.reraise(exceptions.AstroidBuildingException(
+                'Wrong ({encoding}) or no encoding specified for {filename}.',
+                encoding=encoding, filename=filename))
         with stream:
             # get module name if necessary
             if modname is None:
@@ -171,17 +170,10 @@ class AstroidBuilder(raw_building.InspectBuilder):
         """Build tree node from data and add some informations"""
         try:
             node = _parse(data + '\n')
-        except (TypeError, ValueError) as exc:
-            util.reraise(exceptions.AstroidBuildingException(
+        except (TypeError, ValueError, SyntaxError) as exc:
+            util.reraise(exceptions.AstroidSyntaxError(
                 'Parsing Python code failed:\n{error}',
                 source=data, modname=modname, path=path, error=exc))
-        except SyntaxError as exc:
-            # Pass the entire exception object to AstroidBuildingException,
-            # since pylint uses this as an introspection method,
-            # in order to find what error happened.
-            util.reraise(exceptions.AstroidBuildingException(
-                'Syntax error in Python source: {error}',
-                source=data, modname=modname, path=path, error=exc))
         if path is not None:
             node_file = os.path.abspath(path)
         else:
@@ -210,7 +202,7 @@ class AstroidBuilder(raw_building.InspectBuilder):
             if name == '*':
                 try:
                     imported = node.do_import_module()
-                except exceptions.InferenceError:
+                except exceptions.AstroidBuildingException:
                     continue
                 for name in imported.wildcard_import_names():
                     node.parent.set_local(name, node)
diff --git a/astroid/exceptions.py b/astroid/exceptions.py
index e92abc5..3437a1f 100644
--- a/astroid/exceptions.py
+++ b/astroid/exceptions.py
@@ -54,6 +54,14 @@ class AstroidBuildingException(AstroidError):
         super(AstroidBuildingException, self).__init__(message, **kws)
 
 
+class AstroidImportError(AstroidBuildingException):
+    """Exception class used when a module can't be imported by astroid."""
+
+
+class AstroidSyntaxError(AstroidBuildingException):
+    """Exception class used when a module can't be parsed."""
+
+
 class NoDefault(AstroidError):
     """raised by function's `default_value` method when an argument has
     no default value
@@ -96,9 +104,11 @@ class MroError(ResolveError):
                               for m in self.mros)
         return self.message.format(mros=mro_names, cls=self.cls)
 
+
 class DuplicateBasesError(MroError):
     """Error raised when there are duplicate bases in the same class bases."""
 
+
 class InconsistentMroError(MroError):
     """Error raised when a class's MRO is inconsistent."""
 
diff --git a/astroid/inference.py b/astroid/inference.py
index 45f31ff..7b2aa6b 100644
--- a/astroid/inference.py
+++ b/astroid/inference.py
@@ -130,10 +130,16 @@ def infer_import(self, context=None, asname=True):
     name = context.lookupname
     if name is None:
         raise exceptions.InferenceError(node=self, context=context)
-    if asname:
-        yield self.do_import_module(self.real_name(name))
-    else:
-        yield self.do_import_module(name)
+
+    try:
+        if asname:
+            yield self.do_import_module(self.real_name(name))
+        else:
+            yield self.do_import_module(name)
+    except exceptions.AstroidBuildingException as exc:
+        util.reraise(exceptions.InferenceError(node=self, error=exc,
+                                               context=context))        
+        
 nodes.Import._infer = infer_import
 
 
@@ -152,7 +158,13 @@ def infer_import_from(self, context=None, asname=True):
         raise exceptions.InferenceError(node=self, context=context)
     if asname:
         name = self.real_name(name)
-    module = self.do_import_module()
+
+    try:
+        module = self.do_import_module()
+    except exceptions.AstroidBuildingException as exc:
+        util.reraise(exceptions.InferenceError(node=self, error=exc,
+                                               context=context))
+
     try:
         context = contextmod.copy_context(context)
         context.lookupname = name
@@ -277,7 +289,7 @@ def infer_subscript(self, context=None):
     except (IndexError, TypeError, AttributeError) as exc:
         util.reraise(exceptions.InferenceError(node=self, error=exc,
                                                context=context))
-
+        
     # Prevent inferring if the inferred subscript
     # is the same as the original subscripted object.
     if self is assigned or assigned is util.Uninferable:
diff --git a/astroid/manager.py b/astroid/manager.py
index 55a09be..f2aa9d2 100644
--- a/astroid/manager.py
+++ b/astroid/manager.py
@@ -127,16 +127,16 @@ class AstroidManager(object):
                 try:
                     module = modutils.load_module_from_name(modname)
                 except Exception as ex: # pylint: disable=broad-except
-                    util.reraise(exceptions.AstroidBuildingException(
+                    util.reraise(exceptions.AstroidImportError(
                         'Loading {modname} failed with:\n{error}',
                         modname=modname, path=filepath, error=ex))
                 return self.ast_from_module(module, modname)
             elif mp_type == imp.PY_COMPILED:
-                raise exceptions.AstroidBuildingException(
+                raise exceptions.AstroidImportError(
                     "Unable to load compiled module {modname}.",
                     modname=modname, path=filepath)
             if filepath is None:
-                raise exceptions.AstroidBuildingException(
+                raise exceptions.AstroidImportError(
                     "Can't find a file for module {modname}.",
                     modname=modname)
             return self.ast_from_file(filepath, modname, fallback=False)
@@ -182,7 +182,7 @@ class AstroidManager(object):
                     modname.split('.'), context_file=contextfile)
                 traceback = sys.exc_info()[2]
             except ImportError as ex:
-                value = exceptions.AstroidBuildingException(
+                value = exceptions.AstroidImportError(
                     'Failed to import module {modname} with error:\n{error}.',
                     modname=modname, error=ex)
                 traceback = sys.exc_info()[2]
@@ -232,7 +232,7 @@ class AstroidManager(object):
                 'Unable to get module for {class_repr}.',
                 cls=klass, class_repr=safe_repr(klass)))
         except Exception as ex: # pylint: disable=broad-except
-            util.reraise(exceptions.AstroidBuildingException(
+            util.reraise(exceptions.AstroidImportError(
                 'Unexpected error while retrieving module for {class_repr}:\n'
                 '{error}', cls=klass, class_repr=safe_repr(klass), error=ex))
         try:
@@ -242,7 +242,7 @@ class AstroidManager(object):
                 'Unable to get name for {class_repr}:\n',
                 cls=klass, class_repr=safe_repr(klass)))
         except Exception as ex: # pylint: disable=broad-except
-            util.reraise(exceptions.AstroidBuildingException(
+            util.reraise(exceptions.AstroidImportError(
                 'Unexpected error while retrieving name for {class_repr}:\n'
                 '{error}', cls=klass, class_repr=safe_repr(klass), error=ex))
         # take care, on living object __module__ is regularly wrong :(
diff --git a/astroid/mixins.py b/astroid/mixins.py
index 6ee7b4d..e67c9af 100644
--- a/astroid/mixins.py
+++ b/astroid/mixins.py
@@ -125,23 +125,9 @@ class ImportFromMixin(FilterStmtsMixin):
         if mymodule.relative_to_absolute_name(modname, level) == mymodule.name:
             # FIXME: we used to raise InferenceError here, but why ?
             return mymodule
-        try:
-            return mymodule.import_module(modname, level=level,
-                                          relative_only=level and level >= 1)
-        except exceptions.AstroidBuildingException as ex:
-            if isinstance(getattr(ex, 'error', None), SyntaxError):
-                util.reraise(exceptions.InferenceError(
-                    'Could not import {modname} because of SyntaxError:\n'
-                    '{syntax_error}', modname=modname, syntax_error=ex.error,
-                    import_node=self))
-            util.reraise(exceptions.InferenceError('Could not import {modname}.',
-                                                   modname=modname,
-                                                   import_node=self))
-        except SyntaxError as ex:
-            util.reraise(exceptions.InferenceError(
-                'Could not import {modname} because of SyntaxError:\n'
-                '{syntax_error}', modname=modname, syntax_error=ex,
-                import_node=self))
+
+        return mymodule.import_module(modname, level=level,
+                                      relative_only=level and level >= 1)
 
     def real_name(self, asname):
         """get name from 'as' name"""
diff --git a/astroid/tests/testdata/python2/data/invalid_encoding.py b/astroid/tests/testdata/python2/data/invalid_encoding.py
new file mode 100644
index 0000000..dddd208
--- /dev/null
+++ b/astroid/tests/testdata/python2/data/invalid_encoding.py
@@ -0,0 +1 @@
+# -*- coding: lala -*-
\ No newline at end of file
diff --git a/astroid/tests/testdata/python3/data/invalid_encoding.py b/astroid/tests/testdata/python3/data/invalid_encoding.py
new file mode 100644
index 0000000..dddd208
--- /dev/null
+++ b/astroid/tests/testdata/python3/data/invalid_encoding.py
@@ -0,0 +1 @@
+# -*- coding: lala -*-
\ No newline at end of file
diff --git a/astroid/tests/unittest_builder.py b/astroid/tests/unittest_builder.py
index dc161d0..cb5bba9 100644
--- a/astroid/tests/unittest_builder.py
+++ b/astroid/tests/unittest_builder.py
@@ -255,11 +255,11 @@ class BuilderTest(unittest.TestCase):
         self.builder = builder.AstroidBuilder()
 
     def test_data_build_null_bytes(self):
-        with self.assertRaises(exceptions.AstroidBuildingException):
+        with self.assertRaises(exceptions.AstroidSyntaxError):
             self.builder.string_build('\x00')
 
     def test_data_build_invalid_x_escape(self):
-        with self.assertRaises(exceptions.AstroidBuildingException):
+        with self.assertRaises(exceptions.AstroidSyntaxError):
             self.builder.string_build('"\\x1"')
 
     def test_missing_newline(self):
@@ -705,6 +705,10 @@ class FileBuildTest(unittest.TestCase):
             self.assertEqual(len(_locals), 3)
             self.assertEqual(keys, ['autre', 'local', 'self'])
 
+    def test_unknown_encoding(self):
+        with self.assertRaises(exceptions.AstroidSyntaxError):
+            resources.build_file('data/invalid_encoding.py')
+
 
 class ModuleBuildTest(resources.SysPathSetup, FileBuildTest):