Move deprecated module checker to DeprecatedMixin (#4225)

* Move deprecated module checker to DeprecatedMixin

Co-authored-by: Pierre Sassoulas <pierre.sassoulas@gmail.com>

4 files changed, 84 insertions, 12 deletions

diff --git a/ChangeLog b/ChangeLog
index ac5a90330..ea04a5ab9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -15,6 +15,10 @@ Release date: TBA
   alternative to ``extension-pkg-whitelist`` and the message ``blacklisted-name`` is now emitted as
   ``disallowed-name``. The previous names are accepted to maintain backward compatibility.
 
+* Move deprecated checker to ``DeprecatedMixin``
+
+  Closes #4086
+
 
 What's New in Pylint 2.7.3?
 ===========================
diff --git a/pylint/checkers/deprecated.py b/pylint/checkers/deprecated.py
index 9a4f636e4..8aaa02506 100644
--- a/pylint/checkers/deprecated.py
+++ b/pylint/checkers/deprecated.py
@@ -32,6 +32,11 @@ class DeprecatedMixin:
             "deprecated-argument",
             "The argument is marked as deprecated and will be removed in the future.",
         ),
+        "W0402": (
+            "Uses of a deprecated module %r",
+            "deprecated-module",
+            "A module marked as deprecated is imported.",
+        ),
     }
 
     @utils.check_messages(
@@ -47,6 +52,18 @@ class DeprecatedMixin:
         except astroid.InferenceError:
             pass
 
+    @utils.check_messages("deprecated-module")
+    def visit_import(self, node):
+        """triggered when an import statement is seen"""
+        for name in (name for name, _ in node.names):
+            self.check_deprecated_module(node, name)
+
+    @utils.check_messages("deprecated-module")
+    def visit_importfrom(self, node):
+        """triggered when a from statement is seen"""
+        basename = node.modname
+        self.check_deprecated_module(node, basename)
+
     def deprecated_methods(self) -> Container[str]:
         """Callback returning the deprecated methods/functions.
 
@@ -85,6 +102,22 @@ class DeprecatedMixin:
         # pylint: disable=unused-argument
         return ()
 
+    def deprecated_modules(self) -> Iterable:
+        """Callback returning the deprecated modules.
+
+        Returns:
+            collections.abc.Container of deprecated module names.
+        """
+        # pylint: disable=no-self-use
+        return ()
+
+    def check_deprecated_module(self, node, mod_path):
+        """Checks if the module is deprecated"""
+
+        for mod_name in self.deprecated_modules():
+            if mod_path == mod_name or mod_path.startswith(mod_name + "."):
+                self.add_message("deprecated-module", node=node, args=mod_path)
+
     def check_deprecated_method(self, node, inferred):
         """Executes the checker for the given node. This method should
         be called from the checker implementing this mixin.
diff --git a/pylint/checkers/imports.py b/pylint/checkers/imports.py
index 82ff07448..ba14108c4 100644
--- a/pylint/checkers/imports.py
+++ b/pylint/checkers/imports.py
@@ -49,7 +49,7 @@ import astroid
 from astroid import modutils
 from astroid.decorators import cached
 
-from pylint.checkers import BaseChecker
+from pylint.checkers import BaseChecker, DeprecatedMixin
 from pylint.checkers.utils import (
     check_messages,
     is_from_fallback_block,
@@ -292,7 +292,7 @@ DEFAULT_KNOWN_THIRD_PARTY = ("enchant",)
 DEFAULT_PREFERRED_MODULES = ()
 
 
-class ImportsChecker(BaseChecker):
+class ImportsChecker(DeprecatedMixin, BaseChecker):
     """checks for
     * external modules dependencies
     * relative / wildcard imports
@@ -306,13 +306,13 @@ class ImportsChecker(BaseChecker):
     name = "imports"
     msgs = MSGS
     priority = -2
-    deprecated_modules = ("optparse", "tkinter.tix")
+    default_deprecated_modules = ("optparse", "tkinter.tix")
 
     options = (
         (
             "deprecated-modules",
             {
-                "default": deprecated_modules,
+                "default": default_deprecated_modules,
                 "type": "csv",
                 "metavar": "<modules>",
                 "help": "Deprecated modules which should not be used,"
@@ -487,6 +487,10 @@ class ImportsChecker(BaseChecker):
             for cycle in get_cycles(graph, vertices=vertices):
                 self.add_message("cyclic-import", args=" -> ".join(cycle))
 
+    def deprecated_modules(self):
+        """Callback returning the deprecated modules."""
+        return self.config.deprecated_modules
+
     @check_messages(*MSGS)
     def visit_import(self, node):
         """triggered when an import statement is seen"""
@@ -499,7 +503,7 @@ class ImportsChecker(BaseChecker):
             self.add_message("multiple-imports", args=", ".join(names), node=node)
 
         for name in names:
-            self._check_deprecated_module(node, name)
+            self.check_deprecated_module(node, name)
             self._check_preferred_module(node, name)
             imported_module = self._get_imported_module(node, name)
             if isinstance(node.parent, astroid.Module):
@@ -521,7 +525,7 @@ class ImportsChecker(BaseChecker):
 
         self._check_import_as_rename(node)
         self._check_misplaced_future(node)
-        self._check_deprecated_module(node, basename)
+        self.check_deprecated_module(node, basename)
         self._check_preferred_module(node, basename)
         self._check_wildcard_imports(node, imported_module)
         self._check_same_line_imports(node)
@@ -832,12 +836,6 @@ class ImportsChecker(BaseChecker):
             if not self.linter.is_message_enabled("cyclic-import", line=node.lineno):
                 self._excluded_edges[context_name].add(importedmodname)
 
-    def _check_deprecated_module(self, node, mod_path):
-        """check if the module is deprecated"""
-        for mod_name in self.config.deprecated_modules:
-            if mod_path == mod_name or mod_path.startswith(mod_name + "."):
-                self.add_message("deprecated-module", node=node, args=mod_path)
-
     def _check_preferred_module(self, node, mod_path):
         """check if the module has a preferred replacement"""
         if mod_path in self.preferred_modules:
diff --git a/tests/checkers/unittest_deprecated.py b/tests/checkers/unittest_deprecated.py
index f7e8c1309..f9b45cd6d 100644
--- a/tests/checkers/unittest_deprecated.py
+++ b/tests/checkers/unittest_deprecated.py
@@ -12,6 +12,9 @@ class _DeprecatedChecker(DeprecatedMixin, BaseChecker):
     def deprecated_methods(self):
         return {"deprecated_func", ".Deprecated.deprecated_method"}
 
+    def deprecated_modules(self):
+        return {"deprecated_module"}
+
     def deprecated_arguments(self, method):
         if method == "myfunction1":
             # def myfunction1(arg1, deprecated_arg1='spam')
@@ -355,3 +358,37 @@ class TestDeprecatedChecker(CheckerTestCase):
             ),
         ):
             self.checker.visit_call(node)
+
+    def test_deprecated_module(self):
+        # Tests detecting deprecated module
+        node = astroid.extract_node(
+            """
+        import deprecated_module
+        """
+        )
+        with self.assertAddsMessages(
+            Message(
+                msg_id="deprecated-module",
+                args="deprecated_module",
+                node=node,
+                confidence=UNDEFINED,
+            )
+        ):
+            self.checker.visit_import(node)
+
+    def test_deprecated_module_from(self):
+        # Tests detecting deprecated module
+        node = astroid.extract_node(
+            """
+        from deprecated_module import myfunction
+        """
+        )
+        with self.assertAddsMessages(
+            Message(
+                msg_id="deprecated-module",
+                args="deprecated_module",
+                node=node,
+                confidence=UNDEFINED,
+            )
+        ):
+            self.checker.visit_importfrom(node)