Method Py_FrozenMain missing in libpython3.9

[chba]

BPO	42591
Nosy	@vstinner, @encukou, @pablogsal, @miss-islington
PRs	bpo-42591: Export missing Py_FrozenMain() symbol #23730 [3.9] bpo-42591: Export missing Py_FrozenMain() symbol (GH-23730) #23734 bpo-43795: Remove Py_FrozenMain from the Limited API & Stable ABI  #26241 [3.10] bpo-43795: Remove Py_FrozenMain from the Limited API & Stable ABI (GH-26241) #26353

^{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 = None
closed_at = <Date 2020-12-14.23:33:30.176>
created_at = <Date 2020-12-07.16:00:33.880>
labels = ['library', '3.9', '3.10']
title = 'Method Py_FrozenMain missing in libpython3.9'
updated_at = <Date 2021-05-25.11:59:25.858>
user = 'https://bugs.python.org/chba'

bugs.python.org fields:

activity = <Date 2021-05-25.11:59:25.858>
actor = 'pablogsal'
assignee = 'none'
closed = True
closed_date = <Date 2020-12-14.23:33:30.176>
closer = 'vstinner'
components = ['Library (Lib)']
creation = <Date 2020-12-07.16:00:33.880>
creator = 'chba'
dependencies = []
files = []
hgrepos = []
issue_num = 42591
keywords = ['patch']
message_count = 15.0
messages = ['382651', '382817', '382818', '382819', '382829', '382835', '382836', '383021', '383022', '383121', '383123', '383154', '383156', '393878', '394333']
nosy_count = 5.0
nosy_names = ['vstinner', 'petr.viktorin', 'chba', 'pablogsal', 'miss-islington']
pr_nums = ['23730', '23734', '26241', '26353']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue42591'
versions = ['Python 3.9', 'Python 3.10']

[chba]

In Python 3.9.0 and 3.9.1rc1 (Packages from Ubuntu Devel Branch or Fedora) the Method
int Py_FrozenMain(int, char**)
is missing in libpython3.9.so

Thus, when trying the provided freeze example via
freeze.py hello.py & make
one gets the linker error
/usr/bin/ld: frozen.o: in function main': frozen/frozen.c:681: undefined reference to Py_FrozenMain' .

In previous Python 3.8.x the bug does not show.

Thanks,
Chris

[chba]

The same under Python 3.9.1 (Package from Debian bullseye/testing). As the method Py_FrozenMain is contained in the source code, maybe ist has something to do with the build process, a change in makefile? As far as I can see, the builder of the distribution packages call the makefile as provided.

Chris

[chba]

The file containing the source code is Python/frozenmain.c .

[vstinner]

I wrote PR 23730 to fix the issue. Would it be possible for you to test it?

Since Python 3.9, symbols which are not explicitly exported are no longer exported. Python now uses -fvisibility=hidden.

[chba]

Dear Victor,

a simple test with the tools/freeze/hello.py example was successfull with your patch and the newest cpython from github.

1. git clone https://github.com/python/cpython.git
2. Applied a patch of your pull request
   3. configure, make, amke install to xxx
3. freeze.py wants wants this for a very long time:
   ln -s /usr/local/lib/python3.10/config-3.10-x86_64-linux-gnu
   /usr/local/lib/python3.10/config-3.10
4. python3 cpython/Tools/freeze.py -o frozen hello.py
5. cd frozen; make; ./hello
   Helo world...

Thanks again,
Chris

[vstinner]

New changeset b5c7b38 by Victor Stinner in branch 'master':
bpo-42591: Export missing Py_FrozenMain() symbol (GH-23730)
b5c7b38

[vstinner]

a simple test with the tools/freeze/hello.py example was successfull with your patch and the newest cpython from github.

Oh great, thanks for your quick feedback! I applied your PR to master and I will backport it to 3.9.

[vstinner]

New changeset 6b2ed38 by Victor Stinner in branch '3.9':
bpo-42591: Export missing Py_FrozenMain() symbol (GH-23730) (GH-23734)
6b2ed38

[vstinner]

Thanks Christian Bachmaier for the bug report, it's now fixed.

[vstinner]

Christian Bachmaier:

Thus, when trying the provided freeze example via
freeze.py hello.py & make

Do you mean freeze.py from Tools/freeze/freeze.py? This tool seems to be broken for 4 years, since Python 3.6: bpo-42613.

4. freeze.py wants wants this for a very long time:
   ln -s /usr/local/lib/python3.10/config-3.10-x86_64-linux-gnu
   /usr/local/lib/python3.10/config-3.10

Oh, you fixed manually freeze.py?

[chba]

Do you mean freeze.py from Tools/freeze/freeze.py?

Yes, unfortunately I have to keep a large old system running and there are only few options left. It is a University learning system, where students upload program code and then a huge amount of automtic quality checks are executed within a sandbox. The grading is done in a half automtic way. A real alternative is not existing, we tried hard to find one...

This tool seems to
be broken for 4 years, since Python 3.6: bpo-42613.
4. freeze.py wants wants this for a very long time:
ln -s /usr/local/lib/python3.10/config-3.10-x86_64-linux-gnu
/usr/local/lib/python3.10/config-3.10

The symlink does the trick. So it may be easy for you to fix that, so it does operate out of the box again.

[vstinner]

Christian Bachmaier:

The symlink does the trick. So it may be easy for you to fix that, so it does operate out of the box again.

I pushed a fix in bpo-42613. It would be great if you could test it.

See my manual test: https://bugs.python.org/issue42613#msg383153

If you can test it, I can backport the fix to stable branches.

[chba]

Vistor Stinner:

If you can test it, I can backport the fix to stable branches.

Seems to work like a charm. Basically I used the same testing setup as previously on Dec 10th under Debian testing/bullseye without step 2, as master already contains your fix.

Victor, many thanks again, you are great!

[encukou]

Is this function actually usable in Windows? ISTM that you need to define three more functions, PyWinFreeze_ExeInit, PyWinFreeze_ExeTerm and PyInitFrozenExtensions.

Was adding this undocumented function to the Windows stable ABI deliberate? I see no discussion about that.

[pablogsal]

New changeset 68b9c20 by Miss Islington (bot) in branch '3.10':
bpo-43795: Remove Py_FrozenMain from the Limited API & Stable ABI (GH-26241) (GH-26353)
68b9c20