Following files have executable permission bit but have no shebang ("#!"):

Lib/test/ssltests.py
Lib/test/test_pathlib.py
Lib/token.py
Tools/scripts/analyze_dxp.py
Tools/scripts/run_tests.py
Tools/scripts/win_add2path.py
Tools/stringbench/stringbench.py

I think executable bit should be cleared on them, because they can't be ran 
without correct shebang.

Following files have shebang but have no executable permission bit:

Doc/includes/email-alternative.py
Doc/includes/email-dir.py
Doc/includes/email-unpack.py
Lib/difflib.py
Lib/http/cookies.py
Lib/idlelib/PyShell.py
Lib/lib2to3/tests/data/different_encoding.py
Lib/lib2to3/tests/data/false_encoding.py
Lib/mailbox.py
Lib/operator.py
Lib/smtplib.py
Lib/tarfile.py
Lib/test/_test_multiprocessing.py
Lib/test/crashers/recursive_call.py
Lib/test/curses_tests.py
Lib/test/multibytecodec_support.py
Lib/test/test___future__.py
Lib/test/test_bz2.py
Lib/test/test_cmd.py
Lib/test/test_codecencodings_cn.py
Lib/test/test_codecencodings_hk.py
Lib/test/test_codecencodings_iso2022.py
Lib/test/test_codecencodings_jp.py
Lib/test/test_codecencodings_kr.py
Lib/test/test_codecencodings_tw.py
Lib/test/test_codecmaps_cn.py
Lib/test/test_codecmaps_hk.py
Lib/test/test_codecmaps_jp.py
Lib/test/test_codecmaps_kr.py
Lib/test/test_codecmaps_tw.py
Lib/test/test_dbm.py
Lib/test/test_dbm_dumb.py
Lib/test/test_eof.py
Lib/test/test_gzip.py
Lib/test/test_keywordonlyarg.py
Lib/test/test_logging.py
Lib/test/test_marshal.py
Lib/test/test_multibytecodec.py
Lib/test/test_popen.py
Lib/test/test_random.py
Lib/test/test_sched.py
Lib/test/test_smtpnet.py
Lib/test/test_socket.py
Lib/test/test_support.py
Lib/test/test_tcl.py
Lib/test/test_urllib2_localnet.py
Lib/test/test_urllib2net.py
Lib/test/test_urllibnet.py
Lib/test/test_with.py
Lib/test/test_xmlrpc_net.py
Lib/timeit.py
Lib/trace.py
Lib/turtledemo/bytedesign.py
Lib/turtledemo/clock.py
Lib/turtledemo/forest.py
Lib/turtledemo/fractalcurves.py
Lib/turtledemo/lindenmayer.py
Lib/turtledemo/minimal_hanoi.py
Lib/turtledemo/paint.py
Lib/turtledemo/peace.py
Lib/turtledemo/penrose.py
Lib/turtledemo/planet_and_moon.py
Lib/turtledemo/tree.py
Lib/turtledemo/two_canvases.py
Lib/turtledemo/yinyang.py
Lib/webbrowser.py
Mac/Tools/bundlebuilder.py
Mac/Tools/plistlib_generate_testdata.py
Modules/_ctypes/libffi/generate-ios-source-and-headers.py
Modules/_ctypes/libffi/generate-osx-source-and-headers.py
Modules/_decimal/tests/bench.py
Modules/_decimal/tests/deccheck.py
Modules/_decimal/tests/randdec.py
Objects/typeslots.py
Tools/clinic/clinic_test.py
Tools/gdb/libpython.py
Tools/i18n/makelocalealias.py
Tools/pybench/Setup.py
Tools/pybench/clockres.py
Tools/pybench/systimes.py
Tools/scripts/checkpip.py
Tools/ssl/make_ssl_data.py
Tools/test2to3/maintest.py
Tools/unicode/comparecodecs.py
Tools/unittestgui/unittestgui.py

I think most of them should got executable bit.

Exceptions are:

Doc/includes/*.py  -- they are just examples, it can be dangerous set 
executable bit on files which can be exposed via http server.

Lib/test/test_*.py -- they don't purposed to ran with with default system 
Python. Shebangs should be removed.

Lib/test/_test_multiprocessing.py, Lib/test/multibytecodec_support.py -- they 
are just auxiliary modules for other tests. Shebangs should be removed.

Lib/http/cookies.py, Lib/mailbox.py, Lib/operator.py, Modules/_decimal/tests/randdec.py -- they don't do anything. Shebangs should be removed.

Tools/test2to3/maintest.py -- this is Python2 script with Python3 shebang.

Lib/difflib.py -- this just runs doctests. Shebang should be removed.

Following files have shebang but have no executable permission bit. Both should be removed.

Lib/test/test_array.py
Lib/test/test_binhex.py
Lib/test/test_errno.py
Lib/test/test_urlparse.py
Lib/test/test_userstring.py

In Tools/unittestgui/unittestgui.py "python" should be changed to "python3" in the shebang.

Any thoughts?

I like this, and I'm doing this in the Debian/Ubuntu packaging anyway.  But I would like to see some check script which maybe can be run before a release, that points out regressions or wrong permissions for newly introduced files.

New changeset 9062a8695c89 by Stefan Krah in branch '3.3':
Issue #19936: Disable shebang lines in order to prevent using a random
http://hg.python.org/cpython/rev/9062a8695c89

New changeset 92fd0df03823 by Serhiy Storchaka in branch '3.3':
Issue #19936: Added executable bits or shebang lines to Python scripts which
http://hg.python.org/cpython/rev/92fd0df03823

New changeset 83009d70bc9c by Serhiy Storchaka in branch 'default':
Issue #19936: Added executable bits or shebang lines to Python scripts which
http://hg.python.org/cpython/rev/83009d70bc9c

Here is a script. It lists text files with executable bits and without shebangs and files with .py, .pyw, or .sh suffix which have shebang but have not with executable bits.

As far as it searches not only Python files, now it found such files:

- ./python-gdb.py
- ./Doc/includes/email-unpack.py
- ./Doc/includes/email-alternative.py
- ./Doc/includes/email-dir.py
- ./Misc/python-config.sh
x ./Mac/PythonLauncher/MyDocument.m
x ./Mac/PythonLauncher/MyDocument.h
x ./Mac/PythonLauncher/FileSettings.m
x ./Mac/PythonLauncher/main.m
x ./Mac/PythonLauncher/FileSettings.h
- ./Tools/test2to3/maintest.py
x ./Tools/scripts/pydocgui.pyw
x ./Lib/idlelib/idle.bat
- ./Modules/_ctypes/libffi/build-ios.sh
x ./Modules/_ctypes/libffi/ltmain.sh
- ./Modules/_ctypes/libffi/msvcc.sh
- ./Modules/_ctypes/libffi/src/arm/gentramp.sh
x ./Modules/_decimal/tests/deccheck.py
x ./Modules/_decimal/tests/runall.bat
x ./Modules/_decimal/tests/bench.py
x ./PC/msvcrtmodule.c

Somehow Modules/_decimal/tests/bench.py and Modules/_decimal/tests/deccheck.py are now executable, which (I think) they should not be.

New changeset 085a0ea2015f by Serhiy Storchaka in branch '3.3':
Issue #19936: Remove executable bits from C source files and several forgotten
http://hg.python.org/cpython/rev/085a0ea2015f

New changeset 6baeee39195b by Serhiy Storchaka in branch 'default':
Issue #19936: Remove executable bits from C source files and several forgotten
http://hg.python.org/cpython/rev/6baeee39195b

New changeset 334116bb2939 by Serhiy Storchaka in branch '2.7':
Issue #19936: Added executable bits or shebang lines to Python scripts which
http://hg.python.org/cpython/rev/334116bb2939

Left files with mismatched executable bits and shebangs:

Python 3.4:

- ./Doc/includes/email-unpack.py
- ./Doc/includes/email-alternative.py
- ./Doc/includes/email-dir.py
x ./Tools/scripts/pydocgui.pyw
x ./Lib/idlelib/idle.bat
- ./Modules/_ctypes/libffi/build-ios.sh
x ./Modules/_ctypes/libffi/ltmain.sh
- ./Modules/_ctypes/libffi/msvcc.sh
- ./Modules/_ctypes/libffi/src/arm/gentramp.sh
x ./Modules/_decimal/tests/runall.bat

Python 3.3:

- ./Doc/includes/email-unpack.py
- ./Doc/includes/email-alternative.py
- ./Doc/includes/email-dir.py
x ./Lib/idlelib/idle.bat
- ./Modules/_ctypes/libffi/build-ios.sh
x ./Modules/_ctypes/libffi/ltmain.sh
- ./Modules/_ctypes/libffi/msvcc.sh
- ./Modules/_ctypes/libffi/src/arm/gentramp.sh
x ./Modules/_decimal/tests/runall.bat
x ./PC/VS7.1/rt.bat
x ./PC/VC6/rt.bat

Python 2.7:

- ./Doc/includes/email-unpack.py
- ./Doc/includes/email-alternative.py
- ./Doc/includes/email-dir.py
x ./Demo/rpc/test
x ./Lib/idlelib/idle.bat
x ./PC/VS7.1/rt.bat
x ./PC/VC6/rt.bat

IMO the .bat files should have the executable bit as a reminder that they're
executable on Windows.

Gregory, is it intentional that Modules/_ctypes/libffi/build-ios.sh, Modules/_ctypes/libffi/libtool-ldflags, Modules/_ctypes/libffi/msvcc.sh and Modules/_ctypes/libffi/src/arm/gentramp.sh have no executable bits? They all have executable bits in mainstream libffi-3.0.13 distribution.

For those four libffi files in msg208964, do what you want with them.  I ignored executable bits entirely (didn't set or unset) when importing the code as there is zero need to execute any of them.

IMNSHO, I think executable bits should _not_ be set on most files in the Python source tree.  *Especially* not on things under Lib and Lib/test/.  Afterall, any #! on those is *guaranteed* to not refer to the Python interpreter the source tree represents.

New changeset 1cfce469642d by Serhiy Storchaka in branch '3.3':
Issue #19936: Restored executable bits for several libffi files.
http://hg.python.org/cpython/rev/1cfce469642d

New changeset 9adce4e25bdb by Serhiy Storchaka in branch 'default':
Issue #19936: Restored executable bits for several libffi files.
http://hg.python.org/cpython/rev/9adce4e25bdb

Now findnoshebang.py shows only example files in the documentation, Windows-specific bat and pyw files, generated files, and the Modules/_ctypes/libffi/ltmain.sh file. I have not touched ltmain.sh file which have no shebang nor executable bits in the libffi distribution, because I'm not sure this is safe.

Thanks all for reviews.