Merge the empty-string extensions to 'implicit_booleaness_checker'

2 files changed, 56 insertions, 80 deletions

diff --git a/pylint/checkers/refactoring/implicit_booleaness_checker.py b/pylint/checkers/refactoring/implicit_booleaness_checker.py
index ff1a36205..93ac44269 100644
--- a/pylint/checkers/refactoring/implicit_booleaness_checker.py
+++ b/pylint/checkers/refactoring/implicit_booleaness_checker.py
@@ -81,6 +81,15 @@ class ImplicitBooleanessChecker(checkers.BaseChecker):
             "of a collection classes; empty collections are considered as false",
         ),
         "C1804": (
+            '"%s" can be simplified to "%s" as an empty string is falsey',
+            "use-implicit-booleaness-not-comparison-to-string",
+            "Used when Pylint detects comparison to an empty string constant.",
+            {
+                "default_enabled": False,
+                "old_names": [("C1901", "compare-to-empty-string")],
+            },
+        ),
+        "C1805": (
             '"%s" can be simplified to "%s" as 0 is falsey',
             "use-implicit-booleaness-not-comparison-to-zero",
             "Used when Pylint detects comparison to a 0 constant.",
@@ -162,12 +171,16 @@ class ImplicitBooleanessChecker(checkers.BaseChecker):
                 "use-implicit-booleaness-not-len", node=node, confidence=HIGH
             )
 
-    @utils.only_required_for_messages("use-implicit-booleaness-not-comparison")
+    @utils.only_required_for_messages(
+        "use-implicit-booleaness-not-comparison",
+        "use-implicit-booleaness-not-comparison-to-string",
+        "use-implicit-booleaness-not-comparison-to-zero",
+    )
     def visit_compare(self, node: nodes.Compare) -> None:
         self._check_use_implicit_booleaness_not_comparison(node)
         self._check_compare_to_zero(node)
+        self._check_compare_to_string(node)
 
-    @utils.only_required_for_messages("compare-to-zero")
     def _check_compare_to_zero(self, node: nodes.Compare) -> None:
         # pylint: disable=duplicate-code
         _operators = ["!=", "==", "is not", "is"]
@@ -209,6 +222,47 @@ class ImplicitBooleanessChecker(checkers.BaseChecker):
                     confidence=HIGH,
                 )
 
+    def _check_compare_to_string(self, node: nodes.Compare) -> None:
+        """Checks for comparisons to empty string.
+
+        Most of the time you should use the fact that empty strings are false.
+        An exception to this rule is when an empty string value is allowed in the program
+        and has a different meaning than None!
+        """
+        _operators = {"!=", "==", "is not", "is"}
+        # note: astroid.Compare has the left most operand in node.left while the rest
+        # are a list of tuples in node.ops the format of the tuple is
+        # ('compare operator sign', node) here we squash everything into `ops`
+        # to make it easier for processing later
+        ops: list[tuple[str, nodes.NodeNG | None]] = [("", node.left)]
+        ops.extend(node.ops)
+        iter_ops = iter(ops)
+        ops = list(itertools.chain(*iter_ops))  # type: ignore[arg-type]
+        for ops_idx in range(len(ops) - 2):
+            op_1: nodes.NodeNG | None = ops[ops_idx]
+            op_2: str = ops[ops_idx + 1]  # type: ignore[assignment]
+            op_3: nodes.NodeNG | None = ops[ops_idx + 2]
+            error_detected = False
+            if op_1 is None or op_3 is None or op_2 not in _operators:
+                continue
+            node_name = ""
+            # x ?? ""
+            if utils.is_empty_str_literal(op_1):
+                error_detected = True
+                node_name = op_3.as_string()
+            # '' ?? X
+            elif utils.is_empty_str_literal(op_3):
+                error_detected = True
+                node_name = op_1.as_string()
+            if error_detected:
+                suggestion = f"not {node_name}" if op_2 in {"==", "is"} else node_name
+                self.add_message(
+                    "compare-to-empty-string",
+                    args=(node.as_string(), suggestion),
+                    node=node,
+                    confidence=HIGH,
+                )
+
     def _check_use_implicit_booleaness_not_comparison(
         self, node: nodes.Compare
     ) -> None:
diff --git a/pylint/extensions/emptystring.py b/pylint/extensions/emptystring.py
deleted file mode 100644
index 7053187b8..000000000
--- a/pylint/extensions/emptystring.py
+++ /dev/null
@@ -1,78 +0,0 @@
-# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
-# For details: https://github.com/pylint-dev/pylint/blob/main/LICENSE
-# Copyright (c) https://github.com/pylint-dev/pylint/blob/main/CONTRIBUTORS.txt
-
-"""Looks for  comparisons to empty string."""
-
-from __future__ import annotations
-
-import itertools
-from typing import TYPE_CHECKING
-
-from astroid import nodes
-
-from pylint import checkers
-from pylint.checkers import utils
-from pylint.interfaces import HIGH
-
-if TYPE_CHECKING:
-    from pylint.lint import PyLinter
-
-
-class CompareToEmptyStringChecker(checkers.BaseChecker):
-    name = "compare-to-empty-string"
-    msgs = {
-        "C1901": (
-            '"%s" can be simplified to "%s" as an empty string is falsey',
-            "compare-to-empty-string",
-            "Used when Pylint detects comparison to an empty string constant.",
-        )
-    }
-
-    options = ()
-
-    @utils.only_required_for_messages("compare-to-empty-string")
-    def visit_compare(self, node: nodes.Compare) -> None:
-        """Checks for comparisons to empty string.
-
-        Most of the time you should use the fact that empty strings are false.
-        An exception to this rule is when an empty string value is allowed in the program
-        and has a different meaning than None!
-        """
-        _operators = {"!=", "==", "is not", "is"}
-        # note: astroid.Compare has the left most operand in node.left while the rest
-        # are a list of tuples in node.ops the format of the tuple is
-        # ('compare operator sign', node) here we squash everything into `ops`
-        # to make it easier for processing later
-        ops: list[tuple[str, nodes.NodeNG | None]] = [("", node.left)]
-        ops.extend(node.ops)
-        iter_ops = iter(ops)
-        ops = list(itertools.chain(*iter_ops))  # type: ignore[arg-type]
-        for ops_idx in range(len(ops) - 2):
-            op_1: nodes.NodeNG | None = ops[ops_idx]
-            op_2: str = ops[ops_idx + 1]  # type: ignore[assignment]
-            op_3: nodes.NodeNG | None = ops[ops_idx + 2]
-            error_detected = False
-            if op_1 is None or op_3 is None or op_2 not in _operators:
-                continue
-            node_name = ""
-            # x ?? ""
-            if utils.is_empty_str_literal(op_1):
-                error_detected = True
-                node_name = op_3.as_string()
-            # '' ?? X
-            elif utils.is_empty_str_literal(op_3):
-                error_detected = True
-                node_name = op_1.as_string()
-            if error_detected:
-                suggestion = f"not {node_name}" if op_2 in {"==", "is"} else node_name
-                self.add_message(
-                    "compare-to-empty-string",
-                    args=(node.as_string(), suggestion),
-                    node=node,
-                    confidence=HIGH,
-                )
-
-
-def register(linter: PyLinter) -> None:
-    linter.register_checker(CompareToEmptyStringChecker(linter))