Add ``Consider-using-f-string`` checker (#4796)

* Add ``consider-using-f-string`` checker
This adds a checker for normal strings which are formatted
with ``.format()`` or '%'.
The message is a convention to nudge users towards using f-strings.
This closes #3592

* Update pylint code to use f-strings
After adding `consider-using-f-strings` the codebase showed numerous
cases of formatting which could be f-strings.
This commit changes most of these to become f-strings, or adds ignores.

* Apply suggestions from code review

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

5 files changed, 9 insertions, 10 deletions

diff --git a/pylint/reporters/base_reporter.py b/pylint/reporters/base_reporter.py
index 067a32c77..fda99f4ef 100644
--- a/pylint/reporters/base_reporter.py
+++ b/pylint/reporters/base_reporter.py
@@ -42,7 +42,7 @@ class BaseReporter:
         """display results encapsulated in the layout tree"""
         self.section = 0
         if hasattr(layout, "report_id"):
-            layout.children[0].children[0].data += " (%s)" % layout.report_id
+            layout.children[0].children[0].data += f" ({layout.report_id})"
         self._display(layout)
 
     def _display(self, layout):
diff --git a/pylint/reporters/reports_handler_mix_in.py b/pylint/reporters/reports_handler_mix_in.py
index f42824559..914556ef4 100644
--- a/pylint/reporters/reports_handler_mix_in.py
+++ b/pylint/reporters/reports_handler_mix_in.py
@@ -51,7 +51,7 @@ class ReportsHandlerMixIn:
 
     def make_reports(self, stats, old_stats):
         """render registered reports"""
-        sect = Section("Report", "%s statements analysed." % (self.stats["statement"]))
+        sect = Section("Report", f"{self.stats['statement']} statements analysed.")
         for checker in self.report_order():
             for reportid, r_title, r_cb in self._reports[checker]:
                 if not self.report_is_enabled(reportid):
diff --git a/pylint/reporters/text.py b/pylint/reporters/text.py
index 865b3c84d..6d9a05f78 100644
--- a/pylint/reporters/text.py
+++ b/pylint/reporters/text.py
@@ -147,7 +147,7 @@ class TextReporter(BaseReporter):
         """manage message of different type and in the context of path"""
         if msg.module not in self._modules:
             if msg.module:
-                self.writeln("************* Module %s" % msg.module)
+                self.writeln(f"************* Module {msg.module}")
                 self._modules.add(msg.module)
             else:
                 self.writeln("************* ")
@@ -171,8 +171,7 @@ class ParseableTextReporter(TextReporter):
 
     def __init__(self, output=None):
         warnings.warn(
-            "%s output format is deprecated. This is equivalent "
-            "to --msg-template=%s" % (self.name, self.line_format),
+            f"{self.name} output format is deprecated. This is equivalent to --msg-template={self.line_format}",
             DeprecationWarning,
         )
         TextReporter.__init__(self, output)
@@ -227,10 +226,10 @@ class ColorizedTextReporter(TextReporter):
             color, style = self._get_decoration("S")
             if msg.module:
                 modsep = colorize_ansi(
-                    "************* Module %s" % msg.module, color, style
+                    f"************* Module {msg.module}", color, style
                 )
             else:
-                modsep = colorize_ansi("************* %s" % msg.module, color, style)
+                modsep = colorize_ansi(f"************* {msg.module}", color, style)
             self.writeln(modsep)
             self._modules.add(msg.module)
         color, style = self._get_decoration(msg.C)
diff --git a/pylint/reporters/ureports/nodes.py b/pylint/reporters/ureports/nodes.py
index 76d75959c..d359093b8 100644
--- a/pylint/reporters/ureports/nodes.py
+++ b/pylint/reporters/ureports/nodes.py
@@ -50,11 +50,11 @@ class VNode:
             return self.__class__.__name__.lower()
 
     def accept(self, visitor, *args, **kwargs):
-        func = getattr(visitor, "visit_%s" % self._get_visit_name())
+        func = getattr(visitor, f"visit_{self._get_visit_name()}")
         return func(self, *args, **kwargs)
 
     def leave(self, visitor, *args, **kwargs):
-        func = getattr(visitor, "leave_%s" % self._get_visit_name())
+        func = getattr(visitor, f"leave_{self._get_visit_name()}")
         return func(self, *args, **kwargs)
 
 
diff --git a/pylint/reporters/ureports/text_writer.py b/pylint/reporters/ureports/text_writer.py
index 42b03f0ae..a48d73aac 100644
--- a/pylint/reporters/ureports/text_writer.py
+++ b/pylint/reporters/ureports/text_writer.py
@@ -94,4 +94,4 @@ class TextWriter(BaseWriter):
 
     def visit_text(self, layout):
         """add some text"""
-        self.write("%s" % layout.data)
+        self.write(f"{layout.data}")