Optimize effect of disabling import warnings

ChangeLog

@@ -7,6 +7,12 @@ What's New in Pylint 2.0?
 
 Release date: tba
 
+    * Disabling 'wrong-import-order', 'wrong-import-position', or
+      'ungrouped-imports' for a single line now prevents that line from
+      triggering violations on subsequent lines.
+
+      Close #1336
+
     * Added a new error, 'used-prior-global-declaration', which is emitted when a name
       is used prior a global declaration in a function. This causes a SyntaxError in
       Python 3.6

pylint/checkers/imports.py

@@ -425,6 +425,8 @@ def leave_module(self, node):
         met = set()
         current_package = None
         for import_node, import_name in std_imports + ext_imports + loc_imports:
+            if not self.linter.is_message_enabled('ungrouped-imports', import_node.fromlineno):
+                continue
             package, _, _ = import_name.partition('.')
             if current_package and current_package != package and package in met:
                 self.add_message('ungrouped-imports', node=import_node,
@@ -436,6 +438,8 @@ def leave_module(self, node):
         self._first_non_import_node = None
 
     def compute_first_non_import_node(self, node):
+        if not self.linter.is_message_enabled('wrong-import-position', node.fromlineno):
+            return
         # if the node does not contain an import instruction, and if it is the
         # first node of the module, keep a track of it (all the import positions
         # of the module will be compared to the position of this first
@@ -466,6 +470,8 @@ def compute_first_non_import_node(self, node):
         compute_first_non_import_node
 
     def visit_functiondef(self, node):
+        if not self.linter.is_message_enabled('wrong-import-position', node.fromlineno):
+            return
         # If it is the first non import instruction of the module, record it.
         if self._first_non_import_node:
             return
@@ -552,8 +558,8 @@ def _check_imports_order(self, _module_node):
         extern_imports = []
         local_imports = []
         std_imports = []
-        extern_not_nested = []
-        local_not_nested = []
+        extern_not_ignored = []
+        local_not_ignored = []
         isort_obj = isort.SortImports(
             file_contents='', known_third_party=self.config.known_third_party,
             known_standard_library=self.config.known_standard_library,
@@ -564,10 +570,12 @@ def _check_imports_order(self, _module_node):
             else:
                 package = modname.split('.')[0]
             nested = not isinstance(node.parent, astroid.Module)
+            ignore_for_import_order = not self.linter.is_message_enabled('wrong-import-order',
+                                                                         node.fromlineno)
             import_category = isort_obj.place_module(package)
             if import_category in ('FUTURE', 'STDLIB'):
                 std_imports.append((node, package))
-                wrong_import = extern_not_nested or local_not_nested
+                wrong_import = extern_not_ignored or local_not_ignored
                 if self._is_fallback_import(node, wrong_import):
                     continue
                 if wrong_import and not nested:
@@ -576,17 +584,17 @@ def _check_imports_order(self, _module_node):
                                            '"%s"' % wrong_import[0][0].as_string()))
             elif import_category in ('FIRSTPARTY', 'THIRDPARTY'):
                 extern_imports.append((node, package))
-                if not nested:
-                    extern_not_nested.append((node, package))
-                wrong_import = local_not_nested
+                if not nested and not ignore_for_import_order:
+                    extern_not_ignored.append((node, package))
+                wrong_import = local_not_ignored
                 if wrong_import and not nested:
                     self.add_message('wrong-import-order', node=node,
                                      args=('external import "%s"' % node.as_string(),
                                            '"%s"' % wrong_import[0][0].as_string()))
             elif import_category == 'LOCALFOLDER':
                 local_imports.append((node, package))
-                if not nested:
-                    local_not_nested.append((node, package))
+                if not nested and not ignore_for_import_order:
+                    local_not_ignored.append((node, package))
         return std_imports, extern_imports, local_imports
 
     def _get_imported_module(self, importnode, modname):

pylint/test/functional/disable_ungrouped_imports.py

@@ -0,0 +1,10 @@
+"""Checks that disabling 'ungrouped-imports' on an import prevents subsequent
+imports from being considered ungrouped in respect to it."""
+# pylint: disable=unused-import,relative-import,wrong-import-position,wrong-import-order,using-constant-test
+# pylint: disable=import-error
+import os
+import logging.config  # pylint: disable=ungrouped-imports
+import os.path
+import logging
+from os.path import join  # [ungrouped-imports]
+import logging.handlers  # [ungrouped-imports]

pylint/test/functional/disable_ungrouped_imports.txt

@@ -0,0 +1,2 @@
+ungrouped-imports:9::Imports from package os are not grouped
+ungrouped-imports:10::Imports from package logging are not grouped

pylint/test/functional/disable_wrong_import_order.py

@@ -0,0 +1,11 @@
+"""Checks that disabling 'wrong-import-order' on an import prevents subsequent
+imports from being considered out-of-order in respect to it but does not prevent
+it from being considered for 'ungrouped-imports'."""
+# pylint: disable=unused-import,import-error,no-name-in-module
+
+from first_party.foo import bar # pylint: disable=wrong-import-order
+import logging
+import os.path
+import sys
+from astroid import are_exclusive
+import first_party  # [ungrouped-imports]

pylint/test/functional/disable_wrong_import_order.txt

@@ -0,0 +1 @@
+ungrouped-imports:11::Imports from package first_party are not grouped

pylint/test/functional/disable_wrong_import_position.py

@@ -0,0 +1,7 @@
+"""Checks that disabling 'wrong-import-position' on a statement prevents it from
+invalidating subsequent imports."""
+# pylint: disable=unused-import
+
+CONSTANT = True  # pylint: disable=wrong-import-position
+
+import sys