Passing the binary causes it to fail trying to find the `false`
compressor when a binary for a given compressor is not installed.

Gbp-Dch: full
LP: #1926437

We disabled that in 2016, but it does not seem necessary anymore,
seems to break LTO and possibly reduces security.

Closes: #980719

The internal FileFd object now owned the PyObject* that gave us
the descriptor but we were never visiting that object during garbage
collection, so if there was a cycle, Python could not realize that.

Make the objects garbage collectable, by adding VISIT and CLEAR
calls for self->Fd, and by making the FileFd object support garbage
collection in the first place.

correctly

The lines that created self->Fd and that then made use of it were
swapped, causing a segmentation fault.

Also the life of the file object was tracked incorrectly, causing
the file to be closed if it was a temporary one.

Closes: #977000

apt_inst.DebFile provides two members `data` and `control` for
easy access to those tarballs. Each of those members stores a
reference to the DebFile as its owner:

           v-----------------\
        control ----\        |
                     -> deb -|
        data    ----/        |
           ^-----------------/

This means that whenever a DebFile is successfully constructed,
and no longer needed, it won't be collected until the GC runs,
which is bad, as the DebFile holds an open FileFd.

Introduce a __FileFd wrapper that holds the FileFd and becomes
the owner of both control and data, and replaces the direct use
of the FileFd in ArArchive/DebFile:

          v-----------------------------\
        control ----\                    \
                     -> __FileFd <- deb -|
        data    ----/                    /
          ^-----------------------------/

This avoids the reference cycle, ensuring the memory and file
descriptor are released by the reference counter as soon as
the reference count drops to 0.

A future version should move `apt_inst.__FileFd` to `apt_pkg.FileFd`
and expose all the methods, such that people can make use of FileFd's
extensive compression support.

We have a similar cycle in TagFile that we have yet to address,
the problem there is arguably more frustrating, as the buffer
I believe is stored inside the TagFile, and that's really shared
between the TagSection objects.

This is related to LP: #1899193 and CVE-2020-27351, but an additional
hardening measure - the fix for those bugs was for more direct leaks.

Fix various file descritor, and memory leaks in ArArchive, DebFile,
and TagFile by introducing a new PyApt_UniqueObject smart pointer
that is like a unique_ptr, but backportable to older releases, and
automatically clears subobjects, so objects with cycles like DebFile
and TagFile will be released on error paths.

LP: #1899193
GHSL-2020-170
CVE-2020-27351

Varying cases and one is just shortened to medium, but
oh well, it's all better than the previous words.

LP: #1849406

Do not hardcode Debian + Ubuntu codenames, use distro-info-data

See merge request apt-team/python-apt!52

Code cleanup I did not want to mix with the actual work.

Gbp-Dch: ignore

The new name is less confusing, and makes stuff easier, but
also harder for pinning, but who cares really.

and Ubuntu

Read the data from distro-info-data and expand templates
in-memory such that we don't have to duplicate data.

For Ubuntu, this changes some historical releases a bit more, but the
changes do seem correct, and the test suite still passes. Mostly just
some reorganization that was done in later releases passed down to older
releases.

LP: #1727470

Also remove the APT PPA

Mypy 0.790 complains that:

apt/package.py:473: error: Variable "builtins.NotImplemented" is not valid as a type
apt/package.py:473: note: See https://mypy.readthedocs.io/en/latest/common_issues.html#variables-vs-type-aliases

This worked fine in 0.782.

As a workaround, use Any instead of NotImplemented. Ugh

See https://github.com/python/mypy/issues/4791 for more
information.

Fix some issues reported by lintian

See merge request apt-team/python-apt!49

Fix sphinx docs

See merge request apt-team/python-apt!51

Fix a trivial "unused comment" complaint from mypy

Squash lots of warnings about improper C syntax by switching the docs
to use the sphinx cpp domain instead (which also required switching
c:data definitions to cpp:var as the latter domain lacks the "data"
definition).

The highlightlang directive was deprecated in favour of highlight.
Also fix a warning about parsing a code-block (which is actually an
e-mail snippet).

The HashStringList definition is already automatically including
:members: in its output, so the autoattribute:: redundantly re-defines
the "usable" attribute, leading to the warning.

At some point in its history, sphinx switched from using contents.rst to
index.rst as the master document and now warns that if projects aren't
using index.rst they need to explicitly set master_doc in their
configuration.

The defindex.html template has been obsolete for yonks and has been
removed, unremoved, deprecated, and finally (definitely?) removed as
of sphinx 3. See https://github.com/sphinx-doc/sphinx/issues/2986 for
the sordid history :)

Fixes: lintian: out-of-date-standards-version
See-also: https://lintian.debian.org/tags/out-of-date-standards-version.html

Fixes: lintian: debian-changelog-line-too-long
See-also: https://lintian.debian.org/tags/debian-changelog-line-too-long.html

Fixes: lintian: file-contains-trailing-whitespace
See-also: https://lintian.debian.org/tags/file-contains-trailing-whitespace.html

LP: #1874880

This includes, but might not be limited to:

- explicit version checks
- try/except ImportError wrapping of typing imports
- referencing imported types like `Type  # pyflakes` because
  older pyflakes stumbled upon them only being used in `# type`
  comments

Doing this via pybuild is somewhat nasty, as it does not
allow us to move all the common files into the common
package itself, so we have to hack around that.

I'd like to more declaratively state which files belong
into common, or for pybuild to figure that out itself
(it ain't hard), but meh, what can I do?

This fixes the problem where the wildcard that was
matching debug symbols "d-*" (formerly dm-*) also is
matching kfreebsd-, and hence caused FTBFS on freebsd.

Closes: #958118