Fix logging-fstring-interpolation false positive (#7846) (#7854)

Co-authored-by: Mark Byrne <[email protected]>
Co-authored-by: Pierre Sassoulas <[email protected]>
(cherry picked from commit 978d1ab)

Co-authored-by: Dani Alcala <[email protected]>

Author: github-actions[bot]

doc/whatsnew/fragments/4984.false_positive

@@ -0,0 +1,3 @@
+Fix ``logging-fstring-interpolation`` false positive raised when logging and f-string with ``%s`` formatting.
+
+Closes #4984

pylint/checkers/logging.py

@@ -105,6 +105,8 @@
     "warning",
 }
 
+MOST_COMMON_FORMATTING = frozenset(["%s", "%d", "%f", "%r"])
+
 
 def is_method_call(
     func: bases.BoundMethod, types: tuple[str, ...] = (), methods: tuple[str, ...] = ()
@@ -240,8 +242,9 @@ def _check_log_method(self, node: nodes.Call, name: str) -> None:
         else:
             return
 
-        if isinstance(node.args[format_pos], nodes.BinOp):
-            binop = node.args[format_pos]
+        format_arg = node.args[format_pos]
+        if isinstance(format_arg, nodes.BinOp):
+            binop = format_arg
             emit = binop.op == "%"
             if binop.op == "+":
                 total_number_of_strings = sum(
@@ -256,11 +259,13 @@ def _check_log_method(self, node: nodes.Call, name: str) -> None:
                     node=node,
                     args=(self._helper_string(node),),
                 )
-        elif isinstance(node.args[format_pos], nodes.Call):
-            self._check_call_func(node.args[format_pos])
-        elif isinstance(node.args[format_pos], nodes.Const):
+        elif isinstance(format_arg, nodes.Call):
+            self._check_call_func(format_arg)
+        elif isinstance(format_arg, nodes.Const):
             self._check_format_string(node, format_pos)
-        elif isinstance(node.args[format_pos], nodes.JoinedStr):
+        elif isinstance(format_arg, nodes.JoinedStr):
+            if str_formatting_in_f_string(format_arg):
+                return
             self.add_message(
                 "logging-fstring-interpolation",
                 node=node,
@@ -393,5 +398,18 @@ def _count_supplied_tokens(args: list[nodes.NodeNG]) -> int:
     return sum(1 for arg in args if not isinstance(arg, nodes.Keyword))
 
 
+def str_formatting_in_f_string(node: nodes.JoinedStr) -> bool:
+    """Determine whether the node represents an f-string with string formatting.
+
+    For example: `f'Hello %s'`
+    """
+    # Check "%" presence first for performance.
+    return any(
+        "%" in val.value and any(x in val.value for x in MOST_COMMON_FORMATTING)
+        for val in node.values
+        if isinstance(val, nodes.Const)
+    )
+
+
 def register(linter: PyLinter) -> None:
     linter.register_checker(LoggingChecker(linter))

tests/functional/l/logging/logging_fstring_interpolation_py37.py

@@ -3,3 +3,9 @@
 
 VAR = "string"
 logging.error(f"{VAR}")  # [logging-fstring-interpolation]
+
+WORLD = "world"
+logging.error(f'Hello {WORLD}')  # [logging-fstring-interpolation]
+
+logging.error(f'Hello %s', 'World!')  # [f-string-without-interpolation]
+logging.error(f'Hello %d', 1)  # [f-string-without-interpolation]

tests/functional/l/logging/logging_fstring_interpolation_py37.txt

@@ -1 +1,4 @@
 logging-fstring-interpolation:5:0:5:23::Use lazy % formatting in logging functions:UNDEFINED
+logging-fstring-interpolation:8:0:8:31::Use lazy % formatting in logging functions:UNDEFINED
+f-string-without-interpolation:10:14:10:25::Using an f-string that does not have any interpolated variables:UNDEFINED
+f-string-without-interpolation:11:14:11:25::Using an f-string that does not have any interpolated variables:UNDEFINED