Use f-string where possible

CHANGES.txt

@@ -27,6 +27,7 @@ Other
 -----
 
 * Changed filter for tidy from  ``tidy5`` to ``tidy``.
+* Converted from .format() to f-strings
 
 New in v8.3.1
 =============

dodo.py

@@ -53,5 +53,5 @@ def task_gen_completion():
         yield {
             'name': shell,
             'actions': [cmd.format(shell)],
-            'targets': ['_nikola_{0}'.format(shell)],
+            'targets': [f'_nikola_{shell}'],
         }

nikola/__main__.py

@@ -139,15 +139,15 @@ def main(args=None):
     except Exception:
         if os.path.exists(conf_filename):
             msg = traceback.format_exc()
-            LOGGER.error('"{0}" cannot be parsed.\n{1}'.format(conf_filename, msg))
+            LOGGER.error(f'"{conf_filename}" cannot be parsed.\n{msg}')
             return 1
         elif needs_config_file and conf_filename_changed:
-            LOGGER.error('Cannot find configuration file "{0}".'.format(conf_filename))
+            LOGGER.error(f'Cannot find configuration file "{conf_filename}".')
             return 1
         config = {}
 
     if conf_filename_changed:
-        LOGGER.info("Using config file '{0}'".format(conf_filename))
+        LOGGER.info(f"Using config file '{conf_filename}'")
 
     if config:
         if os.path.isdir('plugins') and not os.path.exists('plugins/__init__.py'):
@@ -186,7 +186,7 @@ def print_usage(cmds):
         print("Available commands:")
         for cmd_name in sorted(cmds.keys()):
             cmd = cmds[cmd_name]
-            print("  nikola {:20s} {}".format(cmd_name, cmd.doc_purpose))
+            print(f"  nikola {cmd_name:20s} {cmd.doc_purpose}")
         print("")
         print("  nikola help                 show help / reference")
         print("  nikola help <command>       show command usage")
@@ -359,7 +359,7 @@ def run(self, cmd_args):
             cmd_args = ['version']
             args = ['version']
         if args[0] not in sub_cmds.keys():
-            LOGGER.error("Unknown command {0}".format(args[0]))
+            LOGGER.error(f"Unknown command {args[0]}")
             sugg = defaultdict(list)
             sub_filtered = (i for i in sub_cmds.keys() if i != 'run')
             for c in sub_filtered:
@@ -368,7 +368,7 @@ def run(self, cmd_args):
             if sugg.keys():
                 best_sugg = sugg[min(sugg.keys())]
                 if len(best_sugg) == 1:
-                    LOGGER.info('Did you mean "{}"?'.format(best_sugg[0]))
+                    LOGGER.info(f'Did you mean "{best_sugg[0]}"?')
                 else:
                     LOGGER.info('Did you mean "{}" or "{}"?'.format('", "'.join(best_sugg[:-1]), best_sugg[-1]))
             return 3
@@ -400,7 +400,7 @@ def _command_help(self: Command):
     """Return help text for a command."""
     text = []
 
-    usage = "{} {} {}".format(self.bin_name, self.name, self.doc_usage)
+    usage = f"{self.bin_name} {self.name} {self.doc_usage}"
     text.extend(textwrap.wrap(usage, subsequent_indent='  '))
     text.extend(_wrap(self.doc_purpose, 4))
 
@@ -410,7 +410,7 @@ def _command_help(self: Command):
         options[opt.section].append(opt)
     for section, opts in sorted(options.items()):
         if section:
-            section_name = '\n{}'.format(section)
+            section_name = f'\n{section}'
             text.extend(_wrap(section_name, 2))
         for opt in opts:
             # ignore option that cant be modified on cmd line
@@ -421,15 +421,15 @@ def _command_help(self: Command):
             if '%(default)s' in opt_help:
                 opt_help = opt.help % {'default': opt.default}
             elif opt.default != '' and opt.default is not False and opt.default is not None:
-                opt_help += ' [default: {}]'.format(opt.default)
+                opt_help += f' [default: {opt.default}]'
             opt_choices = opt.help_choices()
-            desc = '{} {}'.format(opt_help, opt_choices)
+            desc = f'{opt_help} {opt_choices}'
             text.extend(_wrap(desc, 8))
 
             # print bool inverse option
             if opt.inverse:
-                text.extend(_wrap('--{}'.format(opt.inverse), 4))
-                text.extend(_wrap('opposite of --{}'.format(opt.long), 8))
+                text.extend(_wrap(f'--{opt.inverse}', 4))
+                text.extend(_wrap(f'opposite of --{opt.long}', 8))
 
     if self.doc_description is not None:
         text.append("\n\nDescription:")

nikola/filters.py

@@ -168,36 +168,33 @@ def yui_compressor(infile, executable=None):
             raise Exception('yui-compressor is not installed.')
             return False
 
-    return runinplace('{} --nomunge %1 -o %2'.format(yuicompressor), infile)
+    return runinplace(f'{yuicompressor} --nomunge %1 -o %2', infile)
 
 
 @_ConfigurableFilter(executable='CLOSURE_COMPILER_EXECUTABLE')
 def closure_compiler(infile, executable='closure-compiler'):
     """Run closure-compiler on a file."""
     return runinplace(
-        '{} --warning_level QUIET --js %1 --js_output_file %2'.format(executable),
-        infile,
+        f'{executable} --warning_level QUIET --js %1 --js_output_file %2', infile
     )
 
 
 @_ConfigurableFilter(executable='OPTIPNG_EXECUTABLE')
 def optipng(infile, executable='optipng'):
     """Run optipng on a file."""
-    return runinplace('{} -preserve -o2 -quiet %1'.format(executable), infile)
+    return runinplace(f'{executable} -preserve -o2 -quiet %1', infile)
 
 
 @_ConfigurableFilter(executable='JPEGOPTIM_EXECUTABLE')
 def jpegoptim(infile, executable='jpegoptim'):
     """Run jpegoptim on a file."""
-    return runinplace('{} -p --strip-all -q %1'.format(executable), infile)
+    return runinplace(f'{executable} -p --strip-all -q %1', infile)
 
 
 @_ConfigurableFilter(executable='JPEGOPTIM_EXECUTABLE')
 def jpegoptim_progressive(infile, executable='jpegoptim'):
     """Run jpegoptim on a file and convert to progressive."""
-    return runinplace(
-        '{} -p --strip-all --all-progressive -q %1'.format(executable), infile
-    )
+    return runinplace(f'{executable} -p --strip-all --all-progressive -q %1', infile)
 
 
 @_ConfigurableFilter(executable='HTML_TIDY_EXECUTABLE')
@@ -532,9 +529,7 @@ def add_header_permalinks(fname, xpath_list=None, file_blacklist=None):
                 hid = node.attrib['id']
 
             new_node = lxml.html.fragment_fromstring(
-                '<a href="#{0}" class="headerlink" title="Permalink to this heading">¶</a>'.format(
-                    hid
-                )
+                f'<a href="#{hid}" class="headerlink" title="Permalink to this heading">¶</a>'
             )
             node.append(new_node)
 
@@ -563,7 +558,7 @@ def deduplicate_ids(data, top_classes=None):
         # Well, that sucks.
         for i in duplicated_ids:
             # Results are ordered the same way they are ordered in document
-            offending_elements = doc.xpath('//*[@id="{}"]'.format(i))
+            offending_elements = doc.xpath(f'//*[@id="{i}"]')
             counter = 2
             # If this is a story or a post, do it from top to bottom, because
             # updates to those are more likely to appear at the bottom of pages.
@@ -578,7 +573,7 @@ def deduplicate_ids(data, top_classes=None):
             for e in off:
                 new_id = i
                 while new_id in seen_ids:
-                    new_id = '{0}-{1}'.format(i, counter)
+                    new_id = f'{i}-{counter}'
                     counter += 1
                 e.attrib['id'] = new_id
                 seen_ids.add(new_id)

nikola/hierarchy_utils.py

@@ -96,13 +96,13 @@ def __str__(self):
     def _repr_partial(self):
         """Return partial representation."""
         if self.parent:
-            return "{0}/{1!r}".format(self.parent._repr_partial(), self.name)
+            return f"{self.parent._repr_partial()}/{self.name!r}"
         else:
             return repr(self.name)
 
     def __repr__(self):
         """Return programmer-friendly node representation."""
-        return "<TreeNode {0}>".format(self._repr_partial())
+        return f"<TreeNode {self._repr_partial()}>"
 
 
 def clone_treenode(treenode, parent=None, acceptor=lambda x: True):
@@ -188,10 +188,10 @@ def parse_escaped_hierarchical_category_name(category_name):
             next_slash = category_name.find('/', index)
         else:
             if len(category_name) == next_backslash + 1:
-                raise Exception("Unexpected '\\' in '{0}' at last position!".format(category_name))
+                raise Exception(f"Unexpected '\\' in '{category_name}' at last position!")
             esc_ch = category_name[next_backslash + 1]
             if esc_ch not in {'/', '\\'}:
-                raise Exception("Unknown escape sequence '\\{0}' in '{1}'!".format(esc_ch, category_name))
+                raise Exception(f"Unknown escape sequence '\\{esc_ch}' in '{category_name}'!")
             current = (current if current else "") + category_name[index:next_backslash] + esc_ch
             index = next_backslash + 2
             next_backslash = category_name.find('\\', index)

nikola/image_processing.py

@@ -106,7 +106,7 @@ def resize_image(self, src, dst=None, max_size=None, bigger_panoramas=True, pres
         if max_sizes is None:
             max_sizes = [max_size]
         if len(max_sizes) != len(dst_paths):
-            raise ValueError('resize_image called with incompatible arguments: {} / {}'.format(dst_paths, max_sizes))
+            raise ValueError(f'resize_image called with incompatible arguments: {dst_paths} / {max_sizes}')
         extension = os.path.splitext(src)[1].lower()
         if extension in {'.svg', '.svgz'}:
             self.resize_svg(src, dst_paths, max_sizes, bigger_panoramas)
@@ -169,8 +169,8 @@ def resize_image(self, src, dst=None, max_size=None, bigger_panoramas=True, pres
 
                 im.save(dst, **save_args)
             except Exception as e:
-                self.logger.warning("Can't process {0}, using original "
-                                    "image! ({1})".format(src, e))
+                self.logger.warning(f"Can't process {src}, using original "
+                                    f"image! ({e})")
                 utils.copy_file(src, dst)
 
     def resize_svg(self, src, dst_paths, max_sizes, bigger_panoramas):
@@ -217,8 +217,8 @@ def resize_svg(self, src, dst_paths, max_sizes, bigger_panoramas):
                 self.logger.warning("No width/height in %s. Original exception: %s" % (src, e))
                 utils.copy_file(src, dst)
             except Exception as e:
-                self.logger.warning("Can't process {0}, using original "
-                                    "image! ({1})".format(src, e))
+                self.logger.warning(f"Can't process {src}, using original "
+                                    f"image! ({e})")
                 utils.copy_file(src, dst)
 
     def image_date(self, src):

nikola/log.py

@@ -178,7 +178,7 @@ def showwarning(message, category, filename, lineno, file=None, line=None):
         n = category.__name__
     except AttributeError:
         n = str(category)
-    get_logger(n).warning("{0}:{1}: {2}".format(filename, lineno, message))
+    get_logger(n).warning(f"{filename}:{lineno}: {message}")
 
 
 warnings.showwarning = showwarning