python scripts: use raw strings (or double-escapes) for regular expression patterns

[SwooshyCueb]

• main
• 4-3-stable

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We have a few regular expresisons in database_connect.py that we use to attempt to find odbc libraries:

irods/scripts/irods/database_connect.py

Lines 111 to 131 in e4b4e8a

	def get_odbc_driver_paths(db_type, oracle_home=None):
	if db_type == 'postgres' or db_type == 'cockroachdb':
	return sorted(unique_list(itertools.chain(
	lib.find_shared_object('psqlodbcw.so'),
	lib.find_shared_object('libodbcpsql.so'),
	lib.find_shared_object('psqlodbc.*\.so', regex=True))),
	key = lambda p: 0 if is_64_bit_ELF(p) else 1)
	elif db_type == 'mysql':
	return sorted(unique_list(itertools.chain(
	lib.find_shared_object('libmaodbc.so'),
	lib.find_shared_object('libmyodbc.so'),
	lib.find_shared_object('libmyodbc5.so'),
	lib.find_shared_object('libmyodbc3.so'),
	lib.find_shared_object('libmyodbc.*\.so', regex=True))),
	key = lambda p: 0 if is_64_bit_ELF(p) else 1)
	elif db_type == 'oracle':
	return sorted(unique_list(itertools.chain(
	lib.find_shared_object('libsqora\.so.*', regex=True, additional_directories=[d for d in [oracle_home] if d]))),
	key = lambda p: 0 if is_64_bit_ELF(p) else 1)
	else:
	raise IrodsError('No default ODBC driver paths for %s' % (db_type))

However, the escapes are not done properly.
From the Python 3.12 documetnation:

Regular expressions use the backslash character ('\') to indicate special forms or to allow special characters to be used without invoking their special meaning. This collides with Python’s usage of the same character for the same purpose in string literals; for example, to match a literal backslash, one might have to write '\\\\' as the pattern string, because the regular expression must be \\, and each backslash must be expressed as \\ inside a regular Python string literal. Also, please note that any invalid escape sequences in Python’s usage of the backslash in string literals now generate a SyntaxWarning and in the future this will become a SyntaxError. This behaviour will happen even if it is a valid escape sequence for a regular expression.

The solution is to use Python’s raw string notation for regular expression patterns; backslashes are not handled in any special way in a string literal prefixed with 'r'. So r"\n" is a two-character string containing '\' and 'n', while "\n" is a one-character string containing a newline. Usually patterns will be expressed in Python code using this raw string notation.

[SwooshyCueb]

I'm expanding this issue to cover regular expressions in all of our python scripts and tests.