Fixed issue where constants.REDIRECTION_TOKENS was being mutated.

Author: kmvanbrunt

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 - Bug Fixes
     - Fixed `ArgparseCompleter.print_help()` not passing file stream to recursive call.
+    - Fixed issue where `constants.REDIRECTION_TOKENS` was being mutated.
 
 ## 3.5.0 (April 13, 2026)
 

cmd2/cmd2.py

@@ -1666,10 +1666,8 @@ def tokens_for_completion(self, line: str, begidx: int, endidx: int) -> tuple[li
                  **On Failure**
                  - Two empty lists
         """
-        import copy
-
         unclosed_quote = ''
-        quotes_to_try = copy.copy(constants.QUOTES)
+        quotes_to_try = [*constants.QUOTES]
 
         tmp_line = line[:endidx]
         tmp_endidx = endidx
@@ -3721,8 +3719,7 @@ def _alias_create(self, args: argparse.Namespace) -> None:
             return
 
         # Unquote redirection and terminator tokens
-        tokens_to_unquote = constants.REDIRECTION_TOKENS
-        tokens_to_unquote.extend(self.statement_parser.terminators)
+        tokens_to_unquote = [*constants.REDIRECTION_TOKENS, *self.statement_parser.terminators]
         utils.unquote_specific_tokens(args.command_args, tokens_to_unquote)
 
         # Build the alias value string
@@ -3801,8 +3798,7 @@ def _alias_list(self, args: argparse.Namespace) -> None:
         """List some or all aliases as 'alias create' commands."""
         self.last_result = {}  # dict[alias_name, alias_value]
 
-        tokens_to_quote = constants.REDIRECTION_TOKENS
-        tokens_to_quote.extend(self.statement_parser.terminators)
+        tokens_to_quote = [*constants.REDIRECTION_TOKENS, *self.statement_parser.terminators]
 
         to_list = utils.remove_duplicates(args.names) if args.names else sorted(self.aliases, key=self.default_sort_key)
 
@@ -3964,8 +3960,7 @@ def _macro_create(self, args: argparse.Namespace) -> None:
             return
 
         # Unquote redirection and terminator tokens
-        tokens_to_unquote = constants.REDIRECTION_TOKENS
-        tokens_to_unquote.extend(self.statement_parser.terminators)
+        tokens_to_unquote = [*constants.REDIRECTION_TOKENS, *self.statement_parser.terminators]
         utils.unquote_specific_tokens(args.command_args, tokens_to_unquote)
 
         # Build the macro value string
@@ -4087,8 +4082,7 @@ def _macro_list(self, args: argparse.Namespace) -> None:
         """List macros."""
         self.last_result = {}  # dict[macro_name, macro_value]
 
-        tokens_to_quote = constants.REDIRECTION_TOKENS
-        tokens_to_quote.extend(self.statement_parser.terminators)
+        tokens_to_quote = [*constants.REDIRECTION_TOKENS, *self.statement_parser.terminators]
 
         to_list = utils.remove_duplicates(args.names) if args.names else sorted(self.macros, key=self.default_sort_key)
 

cmd2/constants.py

@@ -7,12 +7,12 @@
 
 # Used for command parsing, output redirection, tab completion and word
 # breaks. Do not change.
-QUOTES = ['"', "'"]
+QUOTES = ('"', "'")
 REDIRECTION_PIPE = '|'
 REDIRECTION_OUTPUT = '>'
 REDIRECTION_APPEND = '>>'
-REDIRECTION_CHARS = [REDIRECTION_PIPE, REDIRECTION_OUTPUT]
-REDIRECTION_TOKENS = [REDIRECTION_PIPE, REDIRECTION_OUTPUT, REDIRECTION_APPEND]
+REDIRECTION_CHARS = (REDIRECTION_PIPE, REDIRECTION_OUTPUT)
+REDIRECTION_TOKENS = (REDIRECTION_PIPE, REDIRECTION_OUTPUT, REDIRECTION_APPEND)
 COMMENT_CHAR = '#'
 MULTILINE_TERMINATOR = ';'
 

cmd2/parsing.py

@@ -298,10 +298,12 @@ def __init__(
         #       the string (\Z matches the end of the string even if it
         #       contains multiple lines)
         #
-        invalid_command_chars = []
-        invalid_command_chars.extend(constants.QUOTES)
-        invalid_command_chars.extend(constants.REDIRECTION_CHARS)
-        invalid_command_chars.extend(self.terminators)
+        invalid_command_chars = (
+            *constants.QUOTES,
+            *constants.REDIRECTION_CHARS,
+            *self.terminators,
+        )
+
         # escape each item so it will for sure get treated as a literal
         second_group_items = [re.escape(x) for x in invalid_command_chars]
         # add the whitespace and end of string, not escaped because they
@@ -352,9 +354,8 @@ def is_valid_command(self, word: str, *, is_subcommand: bool = False) -> tuple[b
                     return False, errmsg
 
         errmsg = 'cannot contain: whitespace, quotes, '
-        errchars = []
-        errchars.extend(constants.REDIRECTION_CHARS)
-        errchars.extend(self.terminators)
+
+        errchars = (*constants.REDIRECTION_CHARS, *self.terminators)
         errmsg += ', '.join([shlex.quote(x) for x in errchars])
 
         match = self._command_pattern.search(word)
@@ -677,9 +678,8 @@ def split_on_punctuation(self, tokens: list[str]) -> list[str]:
         :param tokens: the tokens as parsed by shlex
         :return: a new list of tokens, further split using punctuation
         """
-        punctuation: list[str] = []
-        punctuation.extend(self.terminators)
-        punctuation.extend(constants.REDIRECTION_CHARS)
+        # Using a set for faster lookups
+        punctuation = {*self.terminators, *constants.REDIRECTION_CHARS}
 
         punctuated_tokens = []