Enabled ruff C4 ruleset and applied fixes

Author: tleonhardt

cmd2/argparse_custom.py

@@ -1031,15 +1031,15 @@ def _format_usage(
 
         # if usage is specified, use that
         if usage is not None:
-            usage %= dict(prog=self._prog)
+            usage %= {"prog": self._prog}
 
         # if no optionals or positionals are available, usage is just prog
         elif not actions:
-            usage = '%(prog)s' % dict(prog=self._prog)
+            usage = '%(prog)s' % {"prog": self._prog}
 
         # if optionals and positionals are available, calculate usage
         else:
-            prog = '%(prog)s' % dict(prog=self._prog)
+            prog = '%(prog)s' % {"prog": self._prog}
 
             # split optionals from positionals
             optionals = []

cmd2/cmd2.py

@@ -411,7 +411,7 @@ def __init__(
         self.max_completion_items = 50
 
         # A dictionary mapping settable names to their Settable instance
-        self._settables: dict[str, Settable] = dict()
+        self._settables: dict[str, Settable] = {}
         self._always_prefix_settables: bool = False
 
         # CommandSet containers
@@ -438,7 +438,7 @@ def __init__(
         self.exclude_from_history = ['eof', 'history']
 
         # Dictionary of macro names and their values
-        self.macros: dict[str, Macro] = dict()
+        self.macros: dict[str, Macro] = {}
 
         # Keeps track of typed command history in the Python shell
         self._py_history: list[str] = []
@@ -447,7 +447,7 @@ def __init__(
         self.py_bridge_name = 'app'
 
         # Defines app-specific variables/functions available in Python shells and pyscripts
-        self.py_locals: dict[str, Any] = dict()
+        self.py_locals: dict[str, Any] = {}
 
         # True if running inside a Python shell or pyscript, False otherwise
         self._in_py = False
@@ -546,7 +546,7 @@ def __init__(
         # Commands that have been disabled from use. This is to support commands that are only available
         # during specific states of the application. This dictionary's keys are the command names and its
         # values are DisabledCommand objects.
-        self.disabled_commands: dict[str, DisabledCommand] = dict()
+        self.disabled_commands: dict[str, DisabledCommand] = {}
 
         # If any command has been categorized, then all other commands that haven't been categorized
         # will display under this section in the help output.
@@ -2889,7 +2889,7 @@ def _redirect_output(self, statement: Statement) -> utils.RedirectionSavedState:
             # Create pipe process in a separate group to isolate our signals from it. If a Ctrl-C event occurs,
             # our sigint handler will forward it only to the most recent pipe process. This makes sure pipe
             # processes close in the right order (most recent first).
-            kwargs: dict[str, Any] = dict()
+            kwargs: dict[str, Any] = {}
             if sys.platform == 'win32':
                 kwargs['creationflags'] = subprocess.CREATE_NEW_PROCESS_GROUP
             else:
@@ -4238,7 +4238,7 @@ def do_shell(self, args: argparse.Namespace) -> None:
         import signal
         import subprocess
 
-        kwargs: dict[str, Any] = dict()
+        kwargs: dict[str, Any] = {}
 
         # Set OS-specific parameters
         if sys.platform.startswith('win'):

cmd2/decorators.py

@@ -437,7 +437,7 @@ def arg_decorator(func: ArgparseCommandFunc[CommandParent]) -> ArgparseCommandFu
         setattr(func, constants.SUBCMD_ATTR_NAME, subcommand)
 
         # Keyword arguments for subparsers.add_parser()
-        add_parser_kwargs: dict[str, Any] = dict()
+        add_parser_kwargs: dict[str, Any] = {}
         if help is not None:
             add_parser_kwargs['help'] = help
         if aliases:

cmd2/table_creator.py

@@ -476,7 +476,7 @@ def __init__(self) -> None:
         total_lines = 0
 
         # Generate the cells for this row
-        cells = list()
+        cells = []
 
         for col_index, col in enumerate(self.cols):
             cell = Cell()

cmd2/utils.py

@@ -757,7 +757,7 @@ class StyleState:
 
         def __init__(self) -> None:
             # Contains styles still in effect, keyed by their index in styles_to_parse
-            self.style_dict: dict[int, str] = dict()
+            self.style_dict: dict[int, str] = {}
 
             # Indexes into style_dict
             self.reset_all: Optional[int] = None

examples/table_creation.py

@@ -74,7 +74,7 @@ def basic_tables():
     """Demonstrates basic examples of the table classes"""
 
     # Table data which demonstrates handling of wrapping and text styles
-    data_list: list[list[Any]] = list()
+    data_list: list[list[Any]] = []
     data_list.append(["Billy Smith", "123 Sesame St.\nFake Town, USA 33445", DollarFormatter(100333.03)])
     data_list.append(
         [
@@ -94,7 +94,7 @@ def basic_tables():
     data_list.append(["John Jones", "9235 Highway 32\n" + green("Greenville") + ", SC 29604", DollarFormatter(82987.71)])
 
     # Table Columns (width does not account for any borders or padding which may be added)
-    columns: list[Column] = list()
+    columns: list[Column] = []
     columns.append(Column("Name", width=20))
     columns.append(Column("Address", width=38))
     columns.append(
@@ -157,7 +157,7 @@ def nested_tables():
 
     # Define table which presents Author data fields vertically with no header.
     # This will be nested in the parent table's first column.
-    author_columns: list[Column] = list()
+    author_columns: list[Column] = []
     author_columns.append(Column("", width=14))
     author_columns.append(Column("", width=20))
 
@@ -172,7 +172,7 @@ def nested_tables():
 
     # Define AlternatingTable for books checked out by people in the first table.
     # This will be nested in the parent table's second column.
-    books_columns: list[Column] = list()
+    books_columns: list[Column] = []
     books_columns.append(Column(ansi.style("Title", bold=True), width=25))
     books_columns.append(
         Column(
@@ -194,7 +194,7 @@ def nested_tables():
 
     # Define BorderedTable for relatives of the author
     # This will be nested in the parent table's third column.
-    relative_columns: list[Column] = list()
+    relative_columns: list[Column] = []
     relative_columns.append(Column(ansi.style("Name", bold=True), width=25))
     relative_columns.append(Column(ansi.style("Relationship", bold=True), width=12))
 
@@ -218,7 +218,7 @@ def nested_tables():
     )
 
     # Define parent AlternatingTable which contains Author and Book tables
-    parent_tbl_columns: list[Column] = list()
+    parent_tbl_columns: list[Column] = []
 
     # All of the nested tables already have background colors. Set style_data_text
     # to False so the parent AlternatingTable does not apply background color to them.

pyproject.toml

@@ -163,7 +163,7 @@ select = [
     "ASYNC", # flake8-async (async await bugs)
     # "B", # flake8-bugbear (various likely bugs and design issues)
     # "BLE", # flake8-blind-except (force more specific exception types than just Exception)
-    # "C4", # flake8-comprehensions (warn about things that could be written as a comprehensions but aren't)
+    "C4",  # flake8-comprehensions (warn about things that could be written as a comprehensions but aren't)
     "C90", # McCabe cyclomatic complexity (warn about functions that are too complex)
     # "COM",  # flake8-commas (forces commas at the end of every type of iterable/container
     # "CPY", # flake8-copyright (warn about missing copyright notice at top of file - currently in preview)