Python’s setup.py raises a ValueError when self.extensions is empty

[jhosmer]

BPO	16537
Nosy	@akuchling, @brettcannon, @ezio-melotti, @merwok, @berkerpeksag, @serhiy-storchaka
Files	Python-2.6.8-setup.py.patch: setup.py patch for 2.6.8 Python-2.7.3-setup.py.patch: setup.py patch for 2.7.3 Python-3.0.1-setup.py.patch: setup.py patch for 3.0.1 Python-3.1.5-setup.py.patch: setup.py patch for 3.1.5 Python-3.2.3-setup.py.patch: setup.py patch for 3.2.3 Python-3.3.0-setup.py.patch: setup.py patch for 3.3.0

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/berkerpeksag'
closed_at = <Date 2014-09-27.19:55:49.953>
created_at = <Date 2012-11-23.01:14:17.055>
labels = ['build']
title = 'Python\xe2\x80\x99s setup.py raises a ValueError when self.extensions is empty'
updated_at = <Date 2014-10-01.02:11:45.785>
user = 'https://bugs.python.org/jhosmer'

bugs.python.org fields:

activity = <Date 2014-10-01.02:11:45.785>
actor = 'python-dev'
assignee = 'berker.peksag'
closed = True
closed_date = <Date 2014-09-27.19:55:49.953>
closer = 'berker.peksag'
components = ['Build']
creation = <Date 2012-11-23.01:14:17.055>
creator = 'jhosmer'
dependencies = []
files = ['28076', '28077', '28078', '28079', '28080', '28081']
hgrepos = []
issue_num = 16537
keywords = ['patch']
message_count = 14.0
messages = ['176142', '176143', '176144', '176145', '176146', '176147', '176148', '176187', '216194', '227717', '227718', '227719', '227752', '228055']
nosy_count = 8.0
nosy_names = ['akuchling', 'brett.cannon', 'ezio.melotti', 'eric.araujo', 'python-dev', 'berker.peksag', 'serhiy.storchaka', 'jhosmer']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'compile error'
url = 'https://bugs.python.org/issue16537'
versions = ['Python 2.7', 'Python 3.4', 'Python 3.5']

[jhosmer]

When disabled_module_list contains all the module names that are not built by Modules/Setup.dist, self.extensions in setup.py will be an empty list and when build_extensions tries to determine the max length of all extension names it raises a ValueError with the following traceback:

Traceback (most recent call last):
  File "./setup.py", line 2143, in <module>
    main()
  File "./setup.py", line 2138, in main
    'Lib/smtpd.py']
  File "/Users/pythonforios/Python_for_iOS/trunk/Python_for_iOS/python2.7/Lib/distutils/core.py", line 152, in setup
    dist.run_commands()
  File "/Users/pythonforios/Python_for_iOS/trunk/Python_for_iOS/python2.7/Lib/distutils/dist.py", line 953, in run_commands
    self.run_command(cmd)
  File "/Users/pythonforios/Python_for_iOS/trunk/Python_for_iOS/python2.7/Lib/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/Users/pythonforios/Python_for_iOS/trunk/Python_for_iOS/python2.7/Lib/distutils/command/build.py", line 127, in run
    self.run_command(cmd_name)
  File "/Users/pythonforios/Python_for_iOS/trunk/Python_for_iOS/python2.7/Lib/distutils/cmd.py", line 326, in run_command
    self.distribution.run_command(command)
  File "/Users/pythonforios/Python_for_iOS/trunk/Python_for_iOS/python2.7/Lib/distutils/dist.py", line 972, in run_command
    cmd_obj.run()
  File "/Users/pythonforios/Python_for_iOS/trunk/Python_for_iOS/python2.7/Lib/distutils/command/build_ext.py", line 339, in run
    self.build_extensions()
  File "./setup.py", line 282, in build_extensions
    longest = max([len(e.name) for e in self.extensions])
ValueError: max() arg is an empty sequence
make: *** [sharedmods] Error 1

```py
disabled_module_list = [
# Modules not compatible/not applicable for the iOS
'dl', 'nis', 'gdbm', 'spwd', '_bsddb', '_curses', '_tkinter', 'readline', 'bsddb185', 'ossaudiodev', 'sunaudiodev', '_curses_panel', 'linuxaudiodev',  
# Modules appended to inittab before embedded initialization
'_multiprocessing', 'future_builtins', '_ctypes_test', '_testcapi', '_sqlite3', '_hashlib', '_hotshot', '_scproxy', '_pybsddb', 'imageop', '_ctypes', '_lsprof', '_heapq', '_yaml', '_json', 'math', 'zlib', '_io', 'bz2', 'dbm'
]
```


~~~ Example [Modules/Setup.dist](https://github.com/python/cpython/blob/main/Modules/Setup.dist): \~\~\~

DESTLIB=$(LIBDEST)
MACHDESTLIB=$(BINLIBDEST)
DESTPATH=
SITEPATH=
TESTPATH=
MACHDEPPATH=:plat-$(MACHDEP)
EXTRAMACHDEPPATH=
TKPATH=:lib-tk
OLDPATH=:lib-old
COREPYTHONPATH=$(DESTPATH)$(SITEPATH)$(TESTPATH)$(MACHDEPPATH)$(EXTRAMACHDEPPATH)$(TKPATH)$(OLDPATH)
PYTHONPATH=$(COREPYTHONPATH)

\*static\*

posix posixmodule.c
errno errnomodule.c
pwd pwdmodule.c
\_sre \_sre.c
\_codecs \_codecsmodule.c
zipimport zipimport.c
\_symtable symtablemodule.c
array arraymodule.c
cmath cmathmodule.c \_math.c
\_struct \_struct.c
time timemodule.c -lm
operator operator.c
\_weakref \_weakref.c
\_random \_randommodule.c
\_collections \_collectionsmodule.c
itertools itertoolsmodule.c
strop stropmodule.c
\_functools \_functoolsmodule.c
\_elementtree -I$(srcdir)/Modules/expat -DHAVE_EXPAT_CONFIG_H -DUSE_PYEXPAT_CAPI \_elementtree.c
datetime datetimemodule.c
\_bisect \_bisectmodule.c
unicodedata unicodedata.c
\_locale \_localemodule.c
fcntl fcntlmodule.c
grp grpmodule.c
select selectmodule.c
mmap mmapmodule.c
\_csv \_csv.c
\_socket socketmodule.c
SSL=/usr/local/OpenSSL_for_iOS
\_ssl \_ssl.c -DUSE_SSL -I$(SSL)/include -I$(SSL)/include/openssl -L$(SSL)/lib -lssl -lcrypto
crypt cryptmodule.c
termios termios.c
resource resource.c
audioop audioop.c
imageop imageop.c
\_md5 md5module.c md5.c
\_sha shamodule.c
\_sha256 sha256module.c
\_sha512 sha512module.c
timing timingmodule.c
syslog syslogmodule.c
binascii binascii.c
parser parsermodule.c
cStringIO cStringIO.c
cPickle cPickle.c
fpectl fpectlmodule.c
fpetest fpetestmodule.c
pyexpat expat/xmlparse.c expat/xmlrole.c expat/xmltok.c pyexpat.c -I$(srcdir)/Modules/expat -DHAVE_EXPAT_CONFIG_H -DUSE_PYEXPAT_CAPI
\_multibytecodec cjkcodecs/multibytecodec.c
\_codecs_cn cjkcodecs/_codecs_cn.c
\_codecs_hk cjkcodecs/_codecs_hk.c
\_codecs_iso2022 cjkcodecs/_codecs_iso2022.c
\_codecs_kr cjkcodecs/_codecs_kr.c
\_codecs_tw cjkcodecs/_codecs_tw.c
\_codecs_jp cjkcodecs/_codecs_jp.c
xxsubtype xxsubtype.c

[jhosmer]

setup.py patch for 2.7.3

[jhosmer]

setup.py patch for 3.0.1

[jhosmer]

setup.py patch for 3.1.5

[jhosmer]

setup.py patch for 3.2.3

[jhosmer]

setup.py patch for 3.3.0

[ezio-melotti]

Thanks for the patches.
3.1 and 2.6 only receive security fixes, and 3.0 is not maintained anymore, so I removed them from the versions. Usually it's enough to upload a single patch, especially if the fix is the same on all branches.
The patch should also include tests if possible.
Is also not necessary to add a comment when you add a file.

[merwok]

LGTM.

[akuchling]

Patch LGTM to me too; someone can probably just commit it.

[python-dev]

New changeset a169ee4f254a by Berker Peksag in branch '3.4':
Issue bpo-16537: Check whether self.extensions is empty in setup.py.
https://hg.python.org/cpython/rev/a169ee4f254a

New changeset 491a4d3e2bdd by Berker Peksag in branch 'default':
Issue bpo-16537: Check whether self.extensions is empty in setup.py.
https://hg.python.org/cpython/rev/491a4d3e2bdd

[python-dev]

New changeset 6946036f21ef by Berker Peksag in branch '2.7':
Issue bpo-16537: Check whether self.extensions is empty in setup.py.
https://hg.python.org/cpython/rev/6946036f21ef

[berkerpeksag]

Committed. Thanks for the patch, Jonathan!