quopri: Unnecessary conditional import

[srittau]

Possible Refactoring

The quopri module conditionally imports binascii and uses custom code if binascii can't be found. For example, the encode() function currently has 60 lines (including empty lines and the docstring), of which only 47 lines are dedicated to the workaround:

cpython/Lib/quopri.py

Lines 44 to 104 in e9ac890

	def encode(input, output, quotetabs, header=False):
	"""Read 'input', apply quoted-printable encoding, and write to 'output'.
	'input' and 'output' are binary file objects. The 'quotetabs' flag
	indicates whether embedded tabs and spaces should be quoted. Note that
	line-ending tabs and spaces are always encoded, as per RFC 1521.
	The 'header' flag indicates whether we are encoding spaces as _ as per RFC
	1522."""
	if b2a_qp is not None:
	data = input.read()
	odata = b2a_qp(data, quotetabs=quotetabs, header=header)
	output.write(odata)
	return
	def write(s, output=output, lineEnd=b'\n'):
	# RFC 1521 requires that the line ending in a space or tab must have
	# that trailing character encoded.
	if s and s[-1:] in b' \t':
	output.write(s[:-1] + quote(s[-1:]) + lineEnd)
	elif s == b'.':
	output.write(quote(s) + lineEnd)
	else:
	output.write(s + lineEnd)
	prevline = None
	while 1:
	line = input.readline()
	if not line:
	break
	outline = []
	# Strip off any readline induced trailing newline
	stripped = b''
	if line[-1:] == b'\n':
	line = line[:-1]
	stripped = b'\n'
	# Calculate the un-length-limited encoded line
	for c in line:
	c = bytes((c,))
	if needsquoting(c, quotetabs, header):
	c = quote(c)
	if header and c == b' ':
	outline.append(b'_')
	else:
	outline.append(c)
	# First, write out the previous line
	if prevline is not None:
	write(prevline)
	# Now see if we need any soft line breaks because of RFC-imposed
	# length limitations. Then do the thisline->prevline dance.
	thisline = EMPTYSTRING.join(outline)
	while len(thisline) > MAXLINESIZE:
	# Don't forget to include the soft line break `=' sign in the
	# length calculation!
	write(thisline[:MAXLINESIZE-1], lineEnd=b'=\n')
	thisline = thisline[MAXLINESIZE-1:]
	# Write out the current line
	prevline = thisline
	# Write out the last line, without a trailing newline
	if prevline is not None:
	write(prevline, lineEnd=stripped)

This is essentially dead code, since I don't think there are any (sane) scenarios nowadays, where binascii is not available. I recommend to remove the conditional import and dead code. I'm willing to write a PR.

Your environment

• CPython versions tested on: Seen on cpython HEAD as of 2022-11-03

[corona10]

This is essentially dead code, since I don't think there are any (sane) scenarios nowadays, where binascii is not available

No, some of the alternative implementations use the CPython library directly, and some of them don't have the implementation for binsacii, I would like to maintain the code as-is.