Fixed misinterpreted modulo sign for consider-using-f-string (#6914)

* Fixed a false positive in consider-using-f-string if the left side of a % is not a string.

* consider-using-f-string: if left side of a \% does not have the attr value it can't be a str

Author: d1gl3

doc/whatsnew/2/2.14/full.rst

@@ -5,6 +5,10 @@ What's New in Pylint 2.14.2?
 ----------------------------
 Release date: TBA
 
+* Fixed a false positive in ``consider-using-f-string`` if the left side of a ``%`` is not a string.
+
+  Closes #6689
+
 * Fixed a false positive in ``unnecessary-list-index-lookup`` and ``unnecessary-dict-index-lookup``
   when the subscript is updated in the body of a nested loop.
 

pylint/checkers/refactoring/recommendation_checker.py

@@ -394,6 +394,12 @@ def _detect_replacable_format_call(self, node: nodes.Const) -> None:
             if "\\" in node.parent.right.as_string():
                 return
 
+            # If % applied to another type than str, it's modulo and can't be replaced by formatting
+            if not hasattr(node.parent.left, "value") or not isinstance(
+                node.parent.left.value, str
+            ):
+                return
+
             inferred_right = utils.safe_infer(node.parent.right)
 
             # If dicts or lists of length > 1 are used

tests/functional/c/consider/consider_using_f_string.py

@@ -72,6 +72,9 @@ def statement_good():
     "{}".format("\n".join(i for i in "string"))
     "%s" % "\n"
     "%s" % "\n".join(i for i in "string")
+    1 % "str"
+    (1, 2) % 'garbage'
+
 
 def statement_bad():
     "String %f" % PARAM_1  # [consider-using-f-string]

tests/functional/c/consider/consider_using_f_string.txt

@@ -8,23 +8,23 @@ consider-using-f-string:51:10:51:21:print_bad:Formatting a regular string which
 consider-using-f-string:52:10:52:21:print_bad:Formatting a regular string which could be a f-string:UNDEFINED
 consider-using-f-string:53:10:53:24:print_bad:Formatting a regular string which could be a f-string:UNDEFINED
 consider-using-f-string:54:10:54:21:print_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:77:4:77:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:78:4:78:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:79:4:79:22:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:80:4:80:11:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:81:4:81:20:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:82:4:82:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:83:4:83:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:84:4:84:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:85:4:85:18:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:80:4:80:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:81:4:81:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:82:4:82:22:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:83:4:83:11:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:84:4:84:20:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:85:4:85:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
 consider-using-f-string:86:4:86:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:109:8:109:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:110:8:110:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:111:8:111:26:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:112:8:112:15:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:113:8:113:24:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:114:8:114:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:115:8:115:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:116:8:116:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
-consider-using-f-string:117:8:117:22:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:87:4:87:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:88:4:88:18:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:89:4:89:15:statement_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:112:8:112:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:113:8:113:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:114:8:114:26:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:115:8:115:15:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:116:8:116:24:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:117:8:117:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
 consider-using-f-string:118:8:118:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:119:8:119:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:120:8:120:22:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED
+consider-using-f-string:121:8:121:19:assignment_bad:Formatting a regular string which could be a f-string:UNDEFINED