@skip_after_libpq(16) uses compile-time libpq version

[df7cb]

While compatibility with PG16 has been fixed in #1582, it's not entirely done yet: In Debian, when testing if upgrading libpq5 from 15 to 16 is safe, the problems fixed in #1582 reappear:

 46s test_ssl_attribute (tests.test_connection.TestConnectionInfo.test_ssl_attribute) ... FAIL
 46s test_ssl_in_use (tests.test_connection.TestConnectionInfo.test_ssl_in_use) ... ok
 46s test_ssl_not_supported (tests.test_connection.TestConnectionInfo.test_ssl_not_supported) ... skipped 'skipped because libpq 150003'

https://ci.debian.net/data/autopkgtest/unstable/amd64/p/psycopg2/37551454/log.gz

This happens when the psycopg2 compiled against libpq5 15 is run with libpq5 16. @skip_after_libpq(16) does not trigger because it uses psycopg2.__libpq_version__ which is statically initialized:

    if (0 > PyModule_AddIntConstant(module,
        "__libpq_version__", PG_VERSION_NUM))
    { return -1; }

In short, this constant shouldn't be a constant, but be loaded at run time.

I tried replacing PG_VERSION_NUM with PQlibVersion(), but that does not seem to be enough, there are other places with more version numbers, and setup.py even redefines its own PG_VERSION _NUM at which point I gave up.

Could someone with more insight into which version number is supposed to mean what check what needs to be done to fix @skip_after_libpq(16) to look at the run-time libpq version? Thanks.

[df7cb]

Fwiw, switching that test to use @skip_after_postgres won't help since the server version in that test is still 15, only libpq5 is used from 16.

[df7cb]

Afaict the problem is a5382d7 which rounds libpq_version() down to __libpq_version__.

[dvarrazzo]

In short, this constant shouldn't be a constant, but be loaded at run time.

The runtime version is available in libpq_version(). The __libpq_version__ is meant exactly to represent the libpq version psycopg was compiled with, and hence which version-depending features were compiled at build time.

[dvarrazzo]

@df7cb could you be so kind to test if the changeset in 55d8899 fixes the problem?

[df7cb]

ERROR: test_ssl_attribute (tests.test_connection.TestConnectionInfo.test_ssl_attribute)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/myon/projects/postgresql/psycopg2/psycopg2/tests/test_connection.py", line 1927, in test_ssl_attribute
    return self.skipTest("libpq runtime version == %s", ext.libpq_version())
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: TestCase.skipTest() takes 2 positional arguments but 3 were given

it works when I change , to %:

return self.skipTest("libpq runtime version == %s" % ext.libpq_version())

test_ssl_attribute (tests.test_connection.TestConnectionInfo.test_ssl_attribute) ... skipped 'libpq runtime version == 160000'
test_ssl_in_use (tests.test_connection.TestConnectionInfo.test_ssl_in_use) ... ok
test_ssl_not_supported (tests.test_connection.TestConnectionInfo.test_ssl_not_supported) ... skipped 'skipped because libpq 150003'

Thanks!

[dvarrazzo]

Oh, silly mistake. Thank you, will commit it with your fix.