Support # noqa: ... pragmas

ChangeLog

@@ -33,6 +33,11 @@ Release date: TBA
 
 * Allow parallel linting when run under Prospector
 
+* ``# noqa: ...` pragmas are now supported as an alternative to
+  ``# pylint: disable=...``.
+
+  Closes #2493
+
 
 What's New in Pylint 2.4.3?
 ===========================

doc/user_guide/message-control.rst

@@ -1,3 +1,5 @@
+.. _messages-control:
+
 Messages control
 ================
 
@@ -25,6 +27,18 @@ For all of these controls, ``pylint`` accepts the following values:
 
 * All the checks with ``all``
 
+.. note::
+
+    ``pylint`` also supports using the ``# noqa: ...`` pragma
+    as an alternative to ``# pylint: disable=...``.
+    Note that other linters may not be able to parse pragmas that use
+    symbolic messages.
+    Therefore is it recommended to use numerical IDs inside ``# noqa`` pragmas
+    when using ``pylint`` with another linter.
+    Disabling ``use-symbolic-message-instead`` may be needed in this case.
+
+    Bare ``# noqa`` pragmas without a list of messages to disable is not supported.
+
 
 Block disables
 --------------

doc/whatsnew/2.5.rst

@@ -32,3 +32,9 @@ Other Changes
   These files can also be passed in on the command line.
 
 * Mutable ``collections.*`` are now flagged as dangerous defaults.
+
+* ``# noqa: ...` pragmas are now supported as an alternative to
+  ``# pylint: disable=...``.
+  See :ref:`messages-control` for detailed usage.
+
+  Closes #2493

pylint/constants.py

@@ -9,6 +9,7 @@
 # so that an option can be continued with the reasons
 # why it is active or disabled.
 OPTION_RGX = re.compile(r"\s*#.*\bpylint:\s*([^;#]+)[;#]{0,1}")
+NOQA_RGX = re.compile(r"# noqa:[\s]?([^;#]+)[;#]{0,1}", re.IGNORECASE)
 
 PY_EXTS = (".py", ".pyc", ".pyo", ".pyw", ".so", ".dll")
 

pylint/lint.py

@@ -68,6 +68,7 @@
 import traceback
 import warnings
 from io import TextIOWrapper
+from typing import List
 
 import astroid
 from astroid import modutils
@@ -76,7 +77,7 @@
 
 from pylint import __pkginfo__, checkers, config, exceptions, interfaces, reporters
 from pylint.__pkginfo__ import version
-from pylint.constants import MAIN_CHECKER_NAME, MSG_TYPES, OPTION_RGX
+from pylint.constants import MAIN_CHECKER_NAME, MSG_TYPES, NOQA_RGX, OPTION_RGX
 from pylint.message import Message, MessageDefinitionStore, MessagesHandlerMixIn
 from pylint.reporters.ureports import nodes as report_nodes
 from pylint.utils import ASTWalker, FileState, utils
@@ -806,6 +807,14 @@ def process_tokens(self, tokens):
 
             if tok_type != tokenize.COMMENT:
                 continue
+
+            # If we did not see a newline between the previous line and now,
+            # we saw a backslash so treat the two lines as one.
+            line_nos = [start[0]]
+            if not saw_newline:
+                line_nos.append(start[0] - 1)
+            self._process_noqa(content, line_nos)
+
             match = OPTION_RGX.search(content)
             if match is None:
                 continue
@@ -846,7 +855,7 @@ def process_tokens(self, tokens):
                 for msgid in utils._splitstrip(value):
                     # Add the line where a control pragma was encountered.
                     if opt in control_pragmas:
-                        self._pragma_lineno[msgid] = start[0]
+                        self._pragma_lineno[msgid] = line_nos[-1]
 
                     try:
                         if (opt, msgid) == ("disable", "all"):
@@ -858,16 +867,30 @@ def process_tokens(self, tokens):
                             self.add_message("file-ignored", line=start[0])
                             self._ignore_file = True
                             return
-                        # If we did not see a newline between the previous line and now,
-                        # we saw a backslash so treat the two lines as one.
-                        if not saw_newline:
-                            meth(msgid, "module", start[0] - 1)
-                        meth(msgid, "module", start[0])
+
+                        for line_no in line_nos:
+                            meth(msgid, "module", line_no)
                     except exceptions.UnknownMessageError:
                         self.add_message("bad-option-value", args=msgid, line=start[0])
             else:
                 self.add_message("unrecognized-inline-option", args=opt, line=start[0])
 
+    def _process_noqa(self, content: str, line_nos: List[int]) -> None:
+        """Find and process any supported noqa pragmas.
+
+        :param content: The comment to parse (including the leading "#").
+        :param line_nos: The line numbers of the lines that the pragma affects.
+        """
+        match = NOQA_RGX.search(content)
+        if not match:
+            return
+
+        for msgid in utils._splitstrip(match.group(1)):
+            for line_no in line_nos:
+                self._pragma_lineno[msgid] = line_no
+                # Ignore unknown messages because this message may not be ours
+                self.disable(msgid, "module", line_no, ignore_unknown=True)
+
     # code checking methods ###################################################
 
     def get_checkers(self):

tests/functional/n/noqa_pragma.py

@@ -0,0 +1,13 @@
+"""Test that a noqa pragma has an effect."""
+# pylint: disable=too-few-public-methods
+
+class Foo:
+    """block-disable test"""
+
+    def meth3(self):
+        """test one line disabling"""
+        print(self.bla)  # noqa: E1101
+
+        print(self.bla)  # noqa: no-member
+
+        self.thing = self.bla  # noqa: E1101, attribute-defined-outside-init

tests/functional/p/pragma_after_backslash.py

@@ -8,3 +8,9 @@ def meth3(self):
         """test one line disabling"""
         print(self.bla) \
            # pylint: disable=E1101
+
+        print(self.bla \
+              + self.bla)  # pylint: disable=E1101
+
+        print(self.bla) \
+           # noqa: E1101