Move from % string formatting syntax to f-string or .format()

doc/conf.py

@@ -55,7 +55,7 @@
 # General information about the project.
 project = "Pylint"
 current_year = datetime.utcnow().year
-copyright = "2003-{year}, Logilab, PyCQA and contributors".format(year=current_year)
+copyright = f"2003-{current_year}, Logilab, PyCQA and contributors"
 
 # The full version, including alpha/beta/rc tags.
 release = version

pylint/checkers/base.py

@@ -1345,12 +1345,12 @@ def is_iterable(internal_node):
                     if is_iterable(default):
                         msg = value.pytype()
                     elif isinstance(default, astroid.Call):
-                        msg = "%s() (%s)" % (value.name, value.qname())
+                        msg = f"{value.name}() ({value.qname()})"
                     else:
-                        msg = "%s (%s)" % (default.as_string(), value.qname())
+                        msg = f"{default.as_string()} ({value.qname()})"
                 else:
                     # this argument is a name
-                    msg = "%s (%s)" % (
+                    msg = "{} ({})".format(
                         default.as_string(),
                         DEFAULT_ARGUMENT_SYMBOLS[value.qname()],
                     )
@@ -1695,7 +1695,7 @@ def _create_naming_options():
         name_type = name_type.replace("_", "-")
         name_options.append(
             (
-                "%s-naming-style" % (name_type,),
+                f"{name_type}-naming-style",
                 {
                     "default": default_style,
                     "type": "choice",
@@ -1708,7 +1708,7 @@ def _create_naming_options():
         )
         name_options.append(
             (
-                "%s-rgx" % (name_type,),
+                f"{name_type}-rgx",
                 {
                     "default": None,
                     "type": "regexp",
@@ -1852,7 +1852,7 @@ def open(self):
         )
         for group in self.config.name_group:
             for name_type in group.split(":"):
-                self._name_group[name_type] = "group_%s" % (group,)
+                self._name_group[name_type] = f"group_{group}"
 
         regexps, hints = self._create_naming_rules()
         self._name_regexps = regexps
@@ -1869,12 +1869,12 @@ def _create_naming_rules(self):
         hints = {}
 
         for name_type in KNOWN_NAME_TYPES:
-            naming_style_option_name = "%s_naming_style" % (name_type,)
+            naming_style_option_name = f"{name_type}_naming_style"
             naming_style_name = getattr(self.config, naming_style_option_name)
 
             regexps[name_type] = NAMING_STYLES[naming_style_name].get_regex(name_type)
 
-            custom_regex_setting_name = "%s_rgx" % (name_type,)
+            custom_regex_setting_name = f"{name_type}_rgx"
             custom_regex = getattr(self.config, custom_regex_setting_name, None)
             if custom_regex is not None:
                 regexps[name_type] = custom_regex
@@ -2448,7 +2448,7 @@ def _is_nan(node) -> bool:
         self.add_message(
             "nan-comparison",
             node=root_node,
-            args=("'{}'".format(root_node.as_string()), suggestion),
+            args=(f"'{root_node.as_string()}'", suggestion),
         )
 
     def _check_literal_comparison(self, literal, node):
@@ -2469,7 +2469,7 @@ def _check_misplaced_constant(self, node, left, right, operator):
         if isinstance(right, astroid.Const):
             return
         operator = REVERSED_COMPS.get(operator, operator)
-        suggestion = "%s %s %r" % (right.as_string(), operator, left.value)
+        suggestion = f"{right.as_string()} {operator} {left.value!r}"
         self.add_message("misplaced-comparison-constant", node=node, args=(suggestion,))
 
     def _check_logical_tautology(self, node):
@@ -2496,7 +2496,7 @@ def _check_logical_tautology(self, node):
             right_operand = right_operand.name
 
         if left_operand == right_operand:
-            suggestion = "%s %s %s" % (left_operand, operator, right_operand)
+            suggestion = f"{left_operand} {operator} {right_operand}"
             self.add_message("comparison-with-itself", node=node, args=(suggestion,))
 
     def _check_callable_comparison(self, node):

pylint/checkers/classes.py

@@ -827,7 +827,7 @@ def _check_proper_bases(self, node):
             if not ancestor:
                 continue
             if isinstance(ancestor, astroid.Instance) and ancestor.is_subtype_of(
-                "%s.type" % (BUILTINS,)
+                f"{BUILTINS}.type"
             ):
                 continue
             if (
@@ -1604,7 +1604,7 @@ def _check_first_arg_config(self, first, config, node, message, method_name):
                 valid = repr(config[0])
             else:
                 valid = ", ".join(repr(v) for v in config[:-1])
-                valid = "%s or %r" % (valid, config[-1])
+                valid = "{} or {!r}".format(valid, config[-1])
             self.add_message(message, args=(method_name, valid), node=node)
 
     def _check_bases_classes(self, node):

pylint/checkers/exceptions.py

@@ -495,7 +495,7 @@ def gather_exceptions_from_handler(
     def visit_binop(self, node):
         if isinstance(node.parent, astroid.ExceptHandler):
             # except (V | A)
-            suggestion = "Did you mean '(%s, %s)' instead?" % (
+            suggestion = "Did you mean '({}, {})' instead?".format(
                 node.left.as_string(),
                 node.right.as_string(),
             )
@@ -505,7 +505,7 @@ def visit_binop(self, node):
     def visit_compare(self, node):
         if isinstance(node.parent, astroid.ExceptHandler):
             # except (V < A)
-            suggestion = "Did you mean '(%s, %s)' instead?" % (
+            suggestion = "Did you mean '({}, {})' instead?".format(
                 node.left.as_string(),
                 ", ".join(operand.as_string() for _, operand in node.ops),
             )
@@ -568,7 +568,7 @@ def visit_tryexcept(self, node):
 
                     for previous_exc in exceptions_classes:
                         if previous_exc in exc_ancestors:
-                            msg = "%s is an ancestor class of %s" % (
+                            msg = "{} is an ancestor class of {}".format(
                                 previous_exc.name,
                                 exc.name,
                             )

pylint/checkers/imports.py

@@ -94,7 +94,7 @@ def _get_import_name(importnode, modname):
 
 def _get_first_import(node, context, name, base, level, alias):
     """return the node where [base.]<name> is imported or None if not found"""
-    fullname = "%s.%s" % (base, name) if base else name
+    fullname = f"{base}.{name}" if base else name
 
     first = None
     found = False
@@ -110,7 +110,7 @@ def _get_first_import(node, context, name, base, level, alias):
         elif isinstance(first, astroid.ImportFrom):
             if level == first.level:
                 for imported_name, imported_alias in first.names:
-                    if fullname == "%s.%s" % (first.modname, imported_name):
+                    if fullname == f"{first.modname}.{imported_name}":
                         found = True
                         break
                     if (
@@ -161,10 +161,10 @@ def _repr_tree_defs(data, indent_str=None):
         else:
             files = "(%s)" % ",".join(sorted(files))
         if indent_str is None:
-            lines.append("%s %s" % (mod, files))
+            lines.append(f"{mod} {files}")
             sub_indent_str = "  "
         else:
-            lines.append(r"%s\-%s %s" % (indent_str, mod, files))
+            lines.append(fr"{indent_str}\-{mod} {files}")
             if i == len(nodes) - 1:
                 sub_indent_str = "%s  " % indent_str
             else:
@@ -197,7 +197,7 @@ def _make_graph(filename, dep_info, sect, gtype):
     report's section
     """
     _dependencies_graph(filename, dep_info)
-    sect.append(Paragraph("%simports graph has been written to %s" % (gtype, filename)))
+    sect.append(Paragraph(f"{gtype}imports graph has been written to {filename}"))
 
 
 # the import checker itself ###################################################
@@ -537,7 +537,7 @@ def visit_importfrom(self, node):
             return
         for name, _ in node.names:
             if name != "*":
-                self._add_imported_module(node, "%s.%s" % (imported_module.name, name))
+                self._add_imported_module(node, f"{imported_module.name}.{name}")
             else:
                 self._add_imported_module(node, imported_module.name)
 

pylint/checkers/misc.py

@@ -107,7 +107,7 @@ def open(self):
 
         notes = "|".join(map(re.escape, self.config.notes))
         if self.config.notes_rgx:
-            regex_string = r"#\s*(%s|%s)\b" % (notes, self.config.notes_rgx)
+            regex_string = fr"#\s*({notes}|{self.config.notes_rgx})\b"
         else:
             regex_string = r"#\s*(%s)\b" % (notes)
 

pylint/checkers/refactoring/not_checker.py

@@ -40,7 +40,7 @@ class NotChecker(checkers.BaseChecker):
     skipped_nodes = (astroid.Set,)
     # 'builtins' py3, '__builtin__' py2
     skipped_classnames = [
-        "%s.%s" % (builtins.__name__, qname) for qname in ("set", "frozenset")
+        f"{builtins.__name__}.{qname}" for qname in ("set", "frozenset")
     ]
 
     @utils.check_messages("unneeded-not")
@@ -77,7 +77,7 @@ def visit_unaryop(self, node):
                     and _type.qname() in self.skipped_classnames
                 ):
                     return
-            suggestion = "%s %s %s" % (
+            suggestion = "{} {} {}".format(
                 left.as_string(),
                 self.reverse_op[operator],
                 right.as_string(),

pylint/checkers/refactoring/refactoring_checker.py

@@ -937,7 +937,7 @@ def _check_consider_using_in(self, node):
         values = list(collections.OrderedDict.fromkeys(values))
         values.remove(common_variable)
         values_string = ", ".join(values) if len(values) != 1 else values[0] + ","
-        suggestion = "%s %s (%s)" % (common_variable, comprehension, values_string)
+        suggestion = f"{common_variable} {comprehension} ({values_string})"
 
         self.add_message("consider-using-in", node=node, args=(suggestion,))
 

pylint/checkers/similar.py

@@ -107,7 +107,7 @@ def _display_sims(self, sims):
             couples = sorted(couples)
             lineset = idx = None
             for lineset, idx in couples:
-                print("==%s:%s" % (lineset.name, idx))
+                print(f"=={lineset.name}:{idx}")
             if lineset:
                 for line in lineset._real_lines[idx : idx + num]:
                     print("  ", line.rstrip())
@@ -404,7 +404,7 @@ def close(self):
             msg = []
             lineset = idx = None
             for lineset, idx in couples:
-                msg.append("==%s:%s" % (lineset.name, idx))
+                msg.append(f"=={lineset.name}:{idx}")
             msg.sort()
 
             if lineset:

pylint/checkers/spelling.py

@@ -66,7 +66,7 @@ class Chunker:  # type: ignore
     br = enchant.Broker()
     dicts = br.list_dicts()
     dict_choices = [""] + [d[0] for d in dicts]
-    dicts = ["%s (%s)" % (d[0], d[1].name) for d in dicts]
+    dicts = ["{} ({})".format(d[0], d[1].name) for d in dicts]
     dicts = ", ".join(dicts)
     instr = ""
 else:
@@ -358,7 +358,7 @@ def _check_spelling(self, msgid, line, line_num):
                     col += 1
                 indicator = (" " * col) + ("^" * len(word))
                 all_suggestion = "' or '".join(suggestions)
-                args = (word, original_line, indicator, "'{}'".format(all_suggestion))
+                args = (word, original_line, indicator, f"'{all_suggestion}'")
                 self.add_message(msgid, line=line_num, args=args)
 
     def process_tokens(self, tokens):

pylint/checkers/strings.py

@@ -227,7 +227,7 @@ def get_access_path(key, parts):
         if is_attribute:
             path.append(f".{specifier}")
         else:
-            path.append("[{!r}]".format(specifier))
+            path.append(f"[{specifier!r}]")
     return str(key) + "".join(path)
 
 

pylint/checkers/typecheck.py

@@ -958,7 +958,7 @@ def visit_attribute(self, node):
             ):
                 continue
 
-            qualname = "{}.{}".format(owner.pytype(), node.attrname)
+            qualname = f"{owner.pytype()}.{node.attrname}"
             if any(
                 pattern.match(qualname) for pattern in self._compiled_generated_members
             ):

pylint/checkers/utils.py

@@ -313,7 +313,7 @@ def clobber_in_except(
     (False, None) otherwise.
     """
     if isinstance(node, astroid.AssignAttr):
-        return True, (node.attrname, "object %r" % (node.expr.as_string(),))
+        return True, (node.attrname, f"object {node.expr.as_string()!r}")
     if isinstance(node, astroid.AssignName):
         name = node.name
         if is_builtin(name):

pylint/checkers/variables.py

@@ -181,7 +181,7 @@ def _get_unpacking_extra_info(node, inferred):
         elif inferred.lineno:
             more = " defined at line %s" % inferred.lineno
     elif inferred.lineno:
-        more = " defined at line %s of %s" % (inferred.lineno, inferred_module)
+        more = f" defined at line {inferred.lineno} of {inferred_module}"
     return more
 
 
@@ -1636,20 +1636,20 @@ def _check_is_unused(self, name, node, stmt, global_names, nonlocal_names):
             else:
                 if isinstance(stmt, astroid.Import):
                     if asname is not None:
-                        msg = "%s imported as %s" % (qname, asname)
+                        msg = f"{qname} imported as {asname}"
                     else:
                         msg = "import %s" % name
                     self.add_message("unused-import", args=msg, node=stmt)
                     return
                 if isinstance(stmt, astroid.ImportFrom):
                     if asname is not None:
-                        msg = "%s imported from %s as %s" % (
+                        msg = "{} imported from {} as {}".format(
                             qname,
                             stmt.modname,
                             asname,
                         )
                     else:
-                        msg = "%s imported from %s" % (name, stmt.modname)
+                        msg = f"{name} imported from {stmt.modname}"
                     self.add_message("unused-import", args=msg, node=stmt)
                     return
                 message_name = "unused-variable"
@@ -2002,7 +2002,7 @@ def _check_imports(self, not_consumed):
                     if as_name is None:
                         msg = "import %s" % imported_name
                     else:
-                        msg = "%s imported as %s" % (imported_name, as_name)
+                        msg = f"{imported_name} imported as {as_name}"
                     if not _is_type_checking_import(stmt):
                         self.add_message("unused-import", args=msg, node=stmt)
                 elif isinstance(stmt, astroid.ImportFrom) and stmt.modname != FUTURE:
@@ -2024,7 +2024,7 @@ def _check_imports(self, not_consumed):
                         self.add_message("unused-wildcard-import", args=name, node=stmt)
                     else:
                         if as_name is None:
-                            msg = "%s imported from %s" % (imported_name, stmt.modname)
+                            msg = f"{imported_name} imported from {stmt.modname}"
                         else:
                             fields = (imported_name, stmt.modname, as_name)
                             msg = "%s imported from %s as %s" % fields

pylint/config/__init__.py

@@ -68,7 +68,7 @@
 
 def _get_pdata_path(base_name, recurs):
     base_name = base_name.replace(os.sep, "_")
-    return os.path.join(PYLINT_HOME, "%s%s%s" % (base_name, recurs, ".stats"))
+    return os.path.join(PYLINT_HOME, "{}{}{}".format(base_name, recurs, ".stats"))
 
 
 def load_results(base):
@@ -91,7 +91,7 @@ def save_results(results, base):
         with open(data_file, "wb") as stream:
             pickle.dump(results, stream)
     except OSError as ex:
-        print("Unable to create file %s: %s" % (data_file, ex), file=sys.stderr)
+        print(f"Unable to create file {data_file}: {ex}", file=sys.stderr)
 
 
 def find_pylintrc():