Add extension checker that suggests any/all statements from for loops (#5196)

* Add extension checker that suggests any/all statements from for loops

* Suggest all/not all: If there are negated conditions, we can suggest
an all/not all statement to move the 'not' out of the comprehension and
call it only once.

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

2 files changed, 82 insertions, 0 deletions

diff --git a/pylint/checkers/utils.py b/pylint/checkers/utils.py
index 43157d0f9..1d198e87e 100644
--- a/pylint/checkers/utils.py
+++ b/pylint/checkers/utils.py
@@ -1638,3 +1638,12 @@ def is_empty_str_literal(node: Optional[nodes.NodeNG]) -> bool:
     return (
         isinstance(node, nodes.Const) and isinstance(node.value, str) and not node.value
     )
+
+
+def returns_bool(node: nodes.NodeNG) -> bool:
+    """Returns true if a node is a return that returns a constant boolean"""
+    return (
+        isinstance(node, nodes.Return)
+        and isinstance(node.value, nodes.Const)
+        and node.value.value in (True, False)
+    )
diff --git a/pylint/extensions/for_any_all.py b/pylint/extensions/for_any_all.py
new file mode 100644
index 000000000..9c7274095
--- /dev/null
+++ b/pylint/extensions/for_any_all.py
@@ -0,0 +1,73 @@
+"""Check for use of for loops that only check for a condition."""
+from typing import TYPE_CHECKING
+
+from astroid import nodes
+
+from pylint.checkers import BaseChecker
+from pylint.checkers.utils import check_messages, returns_bool
+from pylint.interfaces import IAstroidChecker
+
+if TYPE_CHECKING:
+    from pylint.lint.pylinter import PyLinter
+
+
+class ConsiderUsingAnyOrAllChecker(BaseChecker):
+
+    __implements__ = (IAstroidChecker,)
+    name = "consider-using-any-or-all"
+    msgs = {
+        "C0501": (
+            "`for` loop could be '%s'",
+            "consider-using-any-or-all",
+            "A for loop that checks for a condition and return a bool can be replaced with any or all.",
+        )
+    }
+
+    @check_messages("consider-using-any-or-all")
+    def visit_for(self, node: nodes.For) -> None:
+        if len(node.body) != 1:  # Only If node with no Else
+            return
+        if not isinstance(node.body[0], nodes.If):
+            return
+
+        if_children = list(node.body[0].get_children())
+        if not len(if_children) == 2:  # The If node has only a comparison and return
+            return
+        if not returns_bool(if_children[1]):
+            return
+
+        # Check for terminating boolean return right after the loop
+        node_after_loop = node.next_sibling()
+        if returns_bool(node_after_loop):
+            final_return_bool = node_after_loop.value.value
+            suggested_string = self._build_suggested_string(node, final_return_bool)
+            self.add_message(
+                "consider-using-any-or-all", node=node, args=suggested_string
+            )
+
+    @staticmethod
+    def _build_suggested_string(node: nodes.For, final_return_bool: bool) -> str:
+        """When a nodes.For node can be rewritten as an any/all statement, return a suggestion for that statement
+        final_return_bool is the boolean literal returned after the for loop if all conditions fail
+        """
+        loop_var = node.target.as_string()
+        loop_iter = node.iter.as_string()
+        test_node = next(node.body[0].get_children())
+
+        if isinstance(test_node, nodes.UnaryOp) and test_node.op == "not":
+            # The condition is negated. Advance the node to the operand and modify the suggestion
+            test_node = test_node.operand
+            suggested_function = "all" if final_return_bool else "not all"
+        else:
+            suggested_function = "not any" if final_return_bool else "any"
+
+        test = test_node.as_string()
+        return f"{suggested_function}({test} for {loop_var} in {loop_iter})"
+
+
+def register(linter: "PyLinter") -> None:
+    """Required method to auto register this checker.
+
+    :param linter: Main interface object for Pylint plugins
+    """
+    linter.register_checker(ConsiderUsingAnyOrAllChecker(linter))