Do not emit logging-not-lazy for explicitly concatenated strings.

doc/whatsnew/fragments/8410.false_positive

@@ -0,0 +1,3 @@
+`logging-not-lazy` is not longer emitted for explicitly concatenated string arguments.
+
+Closes #8410

pylint/checkers/logging.py

@@ -246,7 +246,7 @@ def _check_log_method(self, node: nodes.Call, name: str) -> None:
         if isinstance(format_arg, nodes.BinOp):
             binop = format_arg
             emit = binop.op == "%"
-            if binop.op == "+":
+            if binop.op == "+" and not self._is_node_explicit_str_concatenation(binop):
                 total_number_of_strings = sum(
                     1
                     for operand in (binop.left, binop.right)
@@ -294,6 +294,19 @@ def _is_operand_literal_str(operand: InferenceResult | None) -> bool:
         """Return True if the operand in argument is a literal string."""
         return isinstance(operand, nodes.Const) and operand.name == "str"
 
+    @staticmethod
+    def _is_node_explicit_str_concatenation(node: nodes.NodeNG) -> bool:
+        """Return True if the node represents an explicitly concatenated string."""
+        if not isinstance(node, nodes.BinOp):
+            return False
+        return (
+            LoggingChecker._is_operand_literal_str(node.left)
+            or LoggingChecker._is_node_explicit_str_concatenation(node.left)
+        ) and (
+            LoggingChecker._is_operand_literal_str(node.right)
+            or LoggingChecker._is_node_explicit_str_concatenation(node.right)
+        )
+
     def _check_call_func(self, node: nodes.Call) -> None:
         """Checks that function call is not format_string.format()."""
         func = utils.safe_infer(node.func)

tests/functional/l/logging/logging_not_lazy.py

@@ -9,10 +9,10 @@
 var_name = "Var:"
 # Statements that should be flagged:
 renamed_logging.warn("%s, %s" % (4, 5))  # [logging-not-lazy]
+renamed_logging.warn("Var: " + var)  # [logging-not-lazy]
 renamed_logging.exception("%s" % "Exceptional!")  # [logging-not-lazy]
 renamed_logging.log(renamed_logging.INFO, "msg: %s" % "Run!")  # [logging-not-lazy]
 renamed_logging.log(renamed_logging.INFO, "Var: " + var)  # [logging-not-lazy]
-renamed_logging.warn("%s" + " the rest of a single string")  # [logging-not-lazy]
 renamed_logging.log(renamed_logging.INFO, var_name + var)  # [logging-not-lazy]
 
 # Statements that should not be flagged:
@@ -21,6 +21,11 @@
 logging.warn("%s, %s" % (4, 5))
 logging.log(logging.INFO, "msg: %s" % "Run!")
 logging.log("Var: " + var)
+# Explicit string concatenations are fine:
+renamed_logging.warn("%s" + " the rest of a single string")
+renamed_logging.warn("Msg: " + "%s", "first piece " + "second piece")
+renamed_logging.warn("first" + "second" + "third %s", "parameter")
+renamed_logging.warn(("first" + "second" + "third %s"))
 
 # Regression crash test for incorrect format call
 renamed_logging.error(

tests/functional/l/logging/logging_not_lazy.txt

@@ -1,8 +1,8 @@
 logging-not-lazy:11:0:11:39::Use lazy % formatting in logging functions:UNDEFINED
-logging-not-lazy:12:0:12:48::Use lazy % formatting in logging functions:UNDEFINED
-logging-not-lazy:13:0:13:61::Use lazy % formatting in logging functions:UNDEFINED
-logging-not-lazy:14:0:14:56::Use lazy % formatting in logging functions:UNDEFINED
-logging-not-lazy:15:0:15:59::Use lazy % formatting in logging functions:UNDEFINED
+logging-not-lazy:12:0:12:35::Use lazy % formatting in logging functions:UNDEFINED
+logging-not-lazy:13:0:13:48::Use lazy % formatting in logging functions:UNDEFINED
+logging-not-lazy:14:0:14:61::Use lazy % formatting in logging functions:UNDEFINED
+logging-not-lazy:15:0:15:56::Use lazy % formatting in logging functions:UNDEFINED
 logging-not-lazy:16:0:16:57::Use lazy % formatting in logging functions:UNDEFINED
-bad-format-string:27:4:27:27::Invalid format string:UNDEFINED
-logging-format-interpolation:27:4:27:27::Use lazy % formatting in logging functions:UNDEFINED
+bad-format-string:32:4:32:27::Invalid format string:UNDEFINED
+logging-format-interpolation:32:4:32:27::Use lazy % formatting in logging functions:UNDEFINED