============
 dh_python3
============

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calculates Python dependencies, adds maintainer scripts to byte compile files, etc.
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:Manual section: 1
:Author: Piotr Ożarowski, 2012-2013

SYNOPSIS
========
  dh_python3 -p PACKAGE [-V [X.Y][-][A.B]] DIR [-X REGEXPR]

DESCRIPTION
===========

QUICK GUIDE FOR MAINTAINERS
---------------------------

 * build depend on dh-python
 * build-depend on python3 (Python application) or python3-all (Python module)
   or python3-all-dev (Python extension),
 * if necessary, describe supported Python 3 versions via X-Python3-Version field
   in debian/control,
 * build module/application using its standard build system (pybuild wrapper
   recommended, see pybuild.1 for more details), remember to build extensions
   for all supported Python 3 versions (loop over ``py3versions -vr``),
 * install files to the *standard* locations, add `--install-layout=deb` to
   setup.py's install command if your package is using distutils,
 * add `python3` to dh's --with option, or:
 * `include /usr/share/cdbs/1/class/python-distutils.mk` in debian/rules and
   depend on `cdbs (>= 0.4.90)`, or:
 * call ``dh_python3`` in the `binary-*` target,
 * add `${python3:Depends}` to Depends

NOTES
-----

dependencies
~~~~~~~~~~~~
dh_python3 tries to translate Python dependencies from the `requires.txt` file
to Debian dependencies. In many cases, this works without any additional
configuration because dh_python3 comes with a build-in mapping of Python module
names to Debian packages that is periodically regenerated from the Debian
archive. By default, the version information in the Python dependencies is
discarded. If you want dh_python3 to generate more strict dependencies (e.g. to
avoid ABI problems), or if the automatic mapping does not work correctly for
your package, you have to provide dh_python3 with additional rules for the
translation of Python module to Debian package dependencies.

For a package *python3-foo* that depends on a package *python3-bar*, there are
two files that may provide such rules:

#. If the *python3-foo* source package ships with a
   `debian/py3dist-overrides` file, this file is used by dh_python3
   during the build of *python3-foo*.

#. If the *python3-bar* source package ships with a
   `debian/python3-bar.pydist` file (and uses dh_python3), this file
   will be included in the binary package as
   `/usr/share/dh-python/dist/cpython3/python3-bar`. During the build
   of *python3-foo*, dh_python3 will then find and use the file.

Both files have the same format described in
`/usr/share/doc/dh-python/README.PyDist`. If all you want is to generate
versioned dependencies (and assuming that the *python3-bar* package provides
the *pybar* Python module), in most cases it will be sufficient to put the line
``pybar python3-bar; PEP386`` into either of the above files.

private dirs
~~~~~~~~~~~~
`/usr/share/foo`, `/usr/share/games/foo`, `/usr/lib/foo` and
`/usr/lib/games/foo` private directories are scanned for Python files
by default (where `foo` is binary package name). If your package ships
Python files in some other directory, add another dh_python3 call in
debian/rules with directory name as an argument - you can use different set of
options in this call. If you need to change options (f.e. a list of supported
Python 3 versions) for a private directory that is checked by default, invoke
dh_python3 with --skip-private option and add another call with a path to this
directory and new options.

debug packages
~~~~~~~~~~~~~~
In binary packages which name ends with `-dbg`, all files in
`/usr/lib/python3/dist-packages/` directory 
that have extensions different than `so` or `h` are removed by default.
Use --no-dbg-cleaning option to disable this feature.

pyinstall files
~~~~~~~~~~~~~~~
Files listed in debian/pkg.pyinstall file will be installed as public modules
(i.e. into .../dist-packages/ directory) for all requested Python versions.

Syntax: ``path/to/file [VERSION_RANGE] [NAMESPACE]``

debian directory is automatically removed from the path, so you can place your
files in debian/ directory and install them from this location (if you want to
install them in "debian" namespace, set NAMESPACE to debian). If NAMESPACE is
set, all listed files will be installed in .../dist-packages/NAMESPACE/
directory.

Examples:
 * ``foo.py`` installs .../dist-packages/foo.py for all supported Python versions
 * ``foo/bar.py 3.3-`` installs .../dist-packages/foo/bar.py for versions >= 3.3
 * ``foo/bar.py spam`` installs .../dist-packages/spam/bar.py
 * ``debian/*.py spam.egg 3.2`` installs .../python3.2/dist-packages/spam/egg/\*.py
   files

pyremove files
~~~~~~~~~~~~~~
If you want to remove some public modules (i.e. files in .../dist-packages/
directory) installed by build system (from all supported Python versions or
only from a subset of these versions), add them to debian/pkg.pyremove file.

Examples:
 * ``*.pth`` removes .pth files from .../dist-packages/
 * ``bar/baz.py 3.2`` removes .../python3.2/dist-packages/bar/baz.py

bcep files
~~~~~~~~~~
Byte-compilation exception patterns can be described in these files. Use it if
you want py3compile to skip specific files. This is the only way to skip .py
files in …/dist-packages/ directory (as `--exclude` passed to py3compile in
postinst is not used in rtupdate scripts and thus this option cannot be used
for non-private modules).

``re|-3.6|/usr/lib/python3/dist-packages/jinja2|.*/async(foo|bar).py``
will skip byte-compilation of `asyncfoo.py` and `asyncbar.py` in
`/usr/lib/python3/dist-packages/jinja2/` directory for each interpreter that
doesn't support `async` keyword (introduced in Python 3.6).

If you want to skip byte-compilation in a subdirectory for all interpreters, use:
``dir|-4.0|/usr/lib/python3/dist-packages/foo/tests/``.
VERSION_RANGE (`-4.0` in the example) is described in `README.PyDist` file.

`debian/python3-foo.bcep` file from source package will be included in the
binary package as `/usr/share/python3/bcep/python3-foo.bcep`

overriding supported / default Python versions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If you want to override system's list of supported Python versions or the
default one (f.e. to build a package that includes symlinks for older version
of Python or compile .py files only for given interpreter version), you can do
that via `DEBPYTHON3_SUPPORTED` and/or `DEBPYTHON3_DEFAULT` env. variables.

Example: ``3.2,3.3`` limits the list of supported Python versions to Python 3.2
and Python 3.3.


OPTIONS
=======
--version	show program's version number and exit

-h, --help	show help message and exit

--no-guessing-deps	disable guessing dependencies

--no-dbg-cleaning	do not remove any files from debug packages

--no-ext-rename		do not add magic tags nor multiarch tuples to extension file names

--no-shebang-rewrite	do not rewrite shebangs

--skip-private	don't check private directories

-v, --verbose	turn verbose mode on

-i, --indep	act on architecture independent packages

-a, --arch	act on architecture dependent packages

-q, --quiet	be quiet

-p PACKAGE, --package=PACKAGE	act on the package named PACKAGE

-N NO_PACKAGE, --no-package=NO_PACKAGE	do not act on the specified package

-V VERSION_RANGE	specify list of supported Python 3 versions. See
  py3compile(1) for examples

-X REGEXPR, --exclude=REGEXPR	exclude items that match given REGEXPR. You may
  use this option multiple times to build up a list of things to exclude from
  byte-compilation in private dirs. See also `bcep files`.

--compile-all	compile all files from given private directory in postinst/rtupdate
  not just the ones provided by the package (i.e. do not pass the --package
  parameter to py3compile/py3clean)

--accept-upstream-versions	accept upstream versions while translating
  Python dependencies into Debian ones

--depends=DEPENDS	translate given requirements into Debian dependencies
  and add them to ${python3:Depends}. Use it for missing items in requires.txt

--depends-section=SECTION	translate requirements from given sections of
  requres.txt file into Debian dependencies and add them to ${python3:Depends}.

--recommends=RECOMMENDS		translate given requirements into Debian dependencies
  and add them to ${python3:Recommends}

--recommends-section=SECTION	translate requirements from given sections of
  requres.txt file into Debian dependencies and add them to ${python3:Recommends}.

--suggests=SUGGESTS	translate given requirements into Debian dependencies
  and add them to ${python3:Suggests}

--suggests-section=SECTION	translate requirements from given sections of
  requres.txt file into Debian dependencies and add them to ${python3:Suggests}.

--requires=FILENAME	translate requirements from given file(s) into Debian
  dependencies and add them to ${python3:Depends}

--shebang=COMMAND	use given command as shebang in scripts

--ignore-shebangs	do not translate shebangs into Debian dependencies

SEE ALSO
========
* /usr/share/doc/python/python-policy.txt.gz
* /usr/share/doc/dh-python/README.PyDist
* pybuild(1)
* py3compile(1), py3clean(1)
* dh_python2(1), pycompile(1), pyclean(1)
* http://deb.li/dhp3 - most recent version of this document