Create new ``UnsupportedVersionChecker`` checker class (#5148)

Co-authored-by: Marc Mueller <30130371+cdce8p@users.noreply.github.com>

4 files changed, 59 insertions, 17 deletions

diff --git a/ChangeLog b/ChangeLog
index 567eaeaa1..e4a957ac5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -29,8 +29,11 @@ Release date: TBA
   ``use-implicit-booleaness-not-len`` in order to be consistent with
   ``use-implicit-booleaness-not-comparison``.
 
-* Added ``using-f-string-in-unsupported-version`` checker. Issued when ``py-version``
-  is set to a version that does not support f-strings (< 3.6)
+* Created new ``UnsupportedVersionChecker`` checker class that includes checks for features
+  not supported by all versions indicated by a ``py-version``.
+
+  * Added ``using-f-string-in-unsupported-version`` checker. Issued when ``py-version``
+    is set to a version that does not support f-strings (< 3.6)
 
 
 What's New in Pylint 2.11.2?
diff --git a/doc/whatsnew/2.12.rst b/doc/whatsnew/2.12.rst
index c143b52a5..68a3dcac4 100644
--- a/doc/whatsnew/2.12.rst
+++ b/doc/whatsnew/2.12.rst
@@ -27,8 +27,11 @@ New checkers
 
   Closes #3197
 
-* Added ``using-f-string-in-unsupported-version`` checker. Issued when ``py-version``
-  is set to a version that does not support f-strings (< 3.6)
+* Created new ``UnsupportedVersionChecker`` checker class that includes checks for features
+  not supported by all versions indicated by a ``py-version``.
+
+  * Added ``using-f-string-in-unsupported-version`` checker. Issued when ``py-version``
+    is set to a version that does not support f-strings (< 3.6)
 
 
 Removed checkers
diff --git a/pylint/checkers/strings.py b/pylint/checkers/strings.py
index 0c93076c5..45b23eee5 100644
--- a/pylint/checkers/strings.py
+++ b/pylint/checkers/strings.py
@@ -47,7 +47,6 @@ from astroid import nodes
 from pylint.checkers import BaseChecker, BaseTokenChecker, utils
 from pylint.checkers.utils import check_messages
 from pylint.interfaces import IAstroidChecker, IRawChecker, ITokenChecker
-from pylint.utils import get_global_option
 
 if TYPE_CHECKING:
     from typing import Counter  # typing.Counter added in Python 3.6.1
@@ -212,12 +211,6 @@ MSGS = {  # pylint: disable=consider-using-namedtuple-or-dataclass
         "Used when we detect a string that does not have any interpolation variables, "
         "in which case it can be either a normal string without formatting or a bug in the code.",
     ),
-    "W1311": (
-        "F-strings are not supported by all versions included in the py-version setting",
-        "using-f-string-in-unsupported-version",
-        "Used when the py-version set by the user is lower than 3.6 and pylint encounters "
-        "a f-string.",
-    ),
 }
 
 OTHER_NODES = (
@@ -417,10 +410,8 @@ class StringFormatChecker(BaseChecker):
                         )
 
     @check_messages("f-string-without-interpolation")
-    @check_messages("using-f-string-in-unsupported-version")
     def visit_joinedstr(self, node: nodes.JoinedStr) -> None:
         self._check_interpolation(node)
-        self._check_unsupported_version(node)
 
     def _check_interpolation(self, node: nodes.JoinedStr) -> None:
         if isinstance(node.parent, nodes.FormattedValue):
@@ -430,10 +421,6 @@ class StringFormatChecker(BaseChecker):
                 return
         self.add_message("f-string-without-interpolation", node=node)
 
-    def _check_unsupported_version(self, node: nodes.JoinedStr) -> None:
-        if get_global_option(self, "py-version") < (3, 6):
-            self.add_message("using-f-string-in-unsupported-version", node=node)
-
     @check_messages(*MSGS)
     def visit_call(self, node: nodes.Call) -> None:
         func = utils.safe_infer(node.func)
diff --git a/pylint/checkers/unsupported_version.py b/pylint/checkers/unsupported_version.py
new file mode 100644
index 000000000..917d64cba
--- /dev/null
+++ b/pylint/checkers/unsupported_version.py
@@ -0,0 +1,49 @@
+# Copyright (c) 2021 Daniël van Noord <13665637+DanielNoord@users.noreply.github.com>
+
+# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+# For details: https://github.com/PyCQA/pylint/blob/main/LICENSE
+
+"""Checker for features used that are not supported by all python versions
+indicated by the py-version setting.
+"""
+
+from astroid import nodes
+
+from pylint.checkers import BaseChecker
+from pylint.checkers.utils import check_messages
+from pylint.interfaces import IAstroidChecker
+from pylint.lint import PyLinter
+from pylint.utils import get_global_option
+
+
+class UnsupportedVersionChecker(BaseChecker):
+    """Checker for features that are not supported by all python versions
+    indicated by the py-version setting.
+    """
+
+    __implements__ = (IAstroidChecker,)
+    name = "unsupported_version"
+    msgs = {
+        "W1601": (
+            "F-strings are not supported by all versions included in the py-version setting",
+            "using-f-string-in-unsupported-version",
+            "Used when the py-version set by the user is lower than 3.6 and pylint encounters "
+            "a f-string.",
+        ),
+    }
+
+    def open(self) -> None:
+        """Initialize visit variables and statistics."""
+        py_version = get_global_option(self, "py-version")
+        self._py36_plus = py_version >= (3, 6)
+
+    @check_messages("using-f-string-in-unsupported-version")
+    def visit_joinedstr(self, node: nodes.JoinedStr) -> None:
+        """Check f-strings"""
+        if not self._py36_plus:
+            self.add_message("using-f-string-in-unsupported-version", node=node)
+
+
+def register(linter: PyLinter) -> None:
+    """Required method to auto register this checker"""
+    linter.register_checker(UnsupportedVersionChecker(linter))