Changelog

Versions follow Semantic Versioning (<major>.<minor>.<patch>). Backward incompatible (breaking) changes will only be introduced in major versions with advance notice in the Deprecations section of releases.

To be included in v1.2.3.dev298+gc4af16a56 (if present)

v1.2.3.dev298+gc4af16a56 [UNRELEASED DRAFT]

(2025-10-10)

Bug fixes

  • The bundled libssh 0.11.2 no longer fails, when the SFTP server announces protocol version 3, but does not provide error message and language tag in the SSH_FXP_STATUS message – by @Jakuje.

    Related issues and pull requests on GitHub: #222.

  • Fixed reading files over SFTP that go over the pre-defined chunk size.

    Prior to this change, the files could end up being corrupted, ending up with the last read chunk written to the file instead of the entire payload.

    – by @Jakuje

    Related issues and pull requests on GitHub: #638.

  • Repetitive calls to exec_channel() no longer crash and return reliable output – by @Jakuje.

    Related issues and pull requests on GitHub: #658.

  • Uploading large files over SCP no longer fails – by @Jakuje.

    Related issues and pull requests on GitHub: #661.

  • Improved performance of SFTP transfers by using larger transfer chunks – by @Jakuje.

    Related issues and pull requests on GitHub: #664.

  • Fixed crash when more operations were called after session.close() – by @Jakuje.

    Related issues and pull requests on GitHub: #709.

Features

  • The underlying SSH_OPTIONS_KEY_EXCHANGE option of libssh is now available as key_exchange_algorithms – by @NilashishC.

    Related issues and pull requests on GitHub: #675.

Deprecations (removal in next major release)

  • The project stopped being tested under Ubuntu 20.04 VM since GitHub has sunset their CI images – by @webknjaz.

    Related issues and pull requests on GitHub: #708.

Removals and backward incompatible breaking changes

  • Dropped support for Python 3.6, 3.7 and 3.8 – by @Qalthos and @webknjaz.

    Related issues and pull requests on GitHub: #532, #718.

  • PyPI no longer ships year-versioned manylinux wheels. One may have to update their version of pip to pick up the new ones.

    – by @webknjaz

    Related issues and pull requests on GitHub: #562.

Improved documentation

  • Added a Communication section to the main documentation page – by @Andersson007.

    Related issues and pull requests on GitHub: #640.

  • Fixed the argument order in the scp.put() usage example – by @kucharskim.

    Related issues and pull requests on GitHub: #646.

Packaging updates and notes for downstreams

  • PyPI now only ships PEP 660-compatible manylinux wheels – by @webknjaz.

    Related issues and pull requests on GitHub: #562.

  • The pytest-forked dependency of build, development and test environments was removed – by @Jakuje.

    Related issues and pull requests on GitHub: #658, #760.

  • The wheels are now built in cached container images with a correctly set platform identifier.

    – by @webknjaz

    Related issues and pull requests on GitHub: #692.

  • The manylinux build scripts now limit cmake below version 4 – by @webknjaz.

    Related issues and pull requests on GitHub: #713.

  • Stopped skipping SCP tests in the RPM spec – by @Jakuje.

    Related issues and pull requests on GitHub: #714.

  • Started bundling a copy of libssh 0.11.1 in platform-specific wheels published on PyPI – by @Jakuje.

    Related issues and pull requests on GitHub: #735.

  • Updated the bundled copy of OpenSSL to the latest version 3.5.0 in manylinux wheels – by @Jakuje.

    Related issues and pull requests on GitHub: #738.

  • Updated the bundled version of libssh to 0.11.2 in platform-specific wheels published on PyPI – by @Jakuje.

    Related issues and pull requests on GitHub: #753.

  • The RPM spec file no longer makes use of unpackaged dists from PyPI on RHEL. The configuration is almost identical to the one for Fedora. Only the setuptools-scm spec is temporarily patched to allow older versions under RHEL.

    – by @webknjaz

    Related issues and pull requests on GitHub: #759.

  • A workaround has been applied to the in-tree build backend that prevents Cython from hanging when libssh header files are missing – by @webknjaz.

    The patch makes cythonize() single-threaded because multiprocessing gets stuck. The upstream will eventually fix this by migrating to concurrent.futures.

    Related issues and pull requests on GitHub: #762, #769, #770.

  • Updated the bundled version of libssh to 0.11.3 in platform-specific wheels published on PyPI – by @Jakuje.

    Related issues and pull requests on GitHub: #766.

Contributor-facing changes

  • The manylinux build scripts have been adjusted to resolve the dependency conflict between certain packaging and setuptools versions – by @webknjaz.

    Previously, this was making some of the CI jobs crash with a traceback when building said wheels.

    Related commits on GitHub: 1dfbf70fdfd99ae75068fdb3630790c96101a96a.

  • The Git archives are now immutable per the packaging recommendations. This allows downstreams safely use GitHub archive URLs when re-packaging – by @webknjaz.

    Related commits on GitHub: ea34887831a0c6547b32cd8c6a035bb77b91e771.

  • Manylinux wheels are no longer built using custom shell scripts. Instead, this is delegated to the cibuildwheel tool.

    – by @webknjaz

    Related issues and pull requests on GitHub: #562.

  • Updated the version of libssh to the latest release v0.11.1 in the cached manylinux build environment container images – by @Jakuje.

    Related issues and pull requests on GitHub: #636.

  • All the uses of actions/upload-artifact@v3 and actions/download-artifact@v3 have been updated to use v4. This also includes bumping re-actors/checkout-python-sdist to release/v2 as it uses actions/download-artifact internally.

    – by @NilashishC and @webknjaz

    Related issues and pull requests on GitHub: #676.

  • The dumb-pypi-produced static package index now renders correct URLs to the distribution packages – by @webknjaz.

    Related issues and pull requests on GitHub: #678, #679, #749.

  • The CI is now configured to use tox run --installpkg when testing pre-built dists. This replaces the previously existing tox-level hacks in test-binary-dists and test-source-dists environments that have now been removed.

    – by @webknjaz

    Related issues and pull requests on GitHub: #688.

  • The wheel building workflows have been updated to set the OCI image platform identifiers to legal values like linux/arm64.

    – by @webknjaz

    Related issues and pull requests on GitHub: #692.

  • The CI is now configured to always set job timeout values. This will ensure that the jobs that get stuck don’t consume all 6 hours just hanging, improving responsiveness and the overall CI/CD resource usage.

    – by @webknjaz

    Related issues and pull requests on GitHub: #706.

  • The linting is now configured to check schemas of the Read The Docs configuration file and the GitHub Actions CI/CD workflow files in addition to enforcing timeouts.

    – by @webknjaz

    Related issues and pull requests on GitHub: #707.

  • The multiarch/qemu-user-static image got replaced with tonistiigi/binfmt because the latter is no longer maintained and the former includes the fixed version of QEMU.

    – by @webknjaz

    Related issues and pull requests on GitHub: #713.

  • Added Fedora 41 and 42 to CI configuration – by @Jakuje.

    Related issues and pull requests on GitHub: #715.

  • Removed needless step from CI adjusting centos8 repositories – by @Jakuje.

    Related issues and pull requests on GitHub: #716.

  • The CI/CD infrastructure no longer pre-builds custom manylinux images for building wheel targeting manylinux1, manylinux2010 and manylinux2014 tags.

    – by @webknjaz

    Related issues and pull requests on GitHub: #730.

  • The host OS is now ARM-based when building manylinux_*_*_aarch64 images for CI/CD – by @webknjaz.

    Related issues and pull requests on GitHub: #731.

  • False negative warnings reported by coveragepy when are now disabled. They are evident when pytest-cov runs with the pytest-xdist integration. pytest 8.4 gives them more visibility and out filterwarnings = error setting was turning them into errors before this change.

    – by @webknjaz

    Related issues and pull requests on GitHub: #732.

  • GitHub Actions CI/CD no longer runs jobs that install source distributions into the tox environments for testing – by @webknjaz.

    This is a temporary workaround for an upstream bug in tox and said jobs are non-essential.

    Related issues and pull requests on GitHub: #733.

  • Updated the pre-built libffi version to 3.4.8 in the cached manylinux build environment container images – by @Jakuje.

    Related issues and pull requests on GitHub: #734.

  • Reverted workaround keeping the old CMake version installed as the new libssh works with newer versions – by @Jakuje.

    Related issues and pull requests on GitHub: #737.

  • The CI infrastructure now produces manylinux_2_31_armv7l base images with libssh and openssl pre-built – by @Jakuje and @webknjaz.

    Related issues and pull requests on GitHub: #740.

  • Started caching manylinux build images to be used for producing 2_34 tagged wheels in build-manylinux-container-images workflow – by @KB-perByte.

    Related issues and pull requests on GitHub: #741.

  • The reusable-cibuildwheel.yml workflow has been refactored to be more generic and ci-cd.yml now holds all the configuration toggles – by @webknjaz.

    Related issues and pull requests on GitHub: #750.

  • Updated the version of libssh to the latest release v0.11.2 in the cached manylinux build environment container images – by @Jakuje.

    Related issues and pull requests on GitHub: #752.

  • When building wheels, the source distribution is now passed directly to the cibuildwheel invocation – by @webknjaz.

    Related issues and pull requests on GitHub: #754.

  • Fixed link to python3-pytest for CentOS 9 Stream as it was recently moved from CRB to AppStream – by @Jakuje.

    Related issues and pull requests on GitHub: #758.

  • The CI/CD jobs for smoke-testing RPMs have been simplified and now, they execute the same steps for all distro types. They make use of pyproject-rpm-macros even under RHEL. Installing external RPMs is the only conditional step that is skipped on Fedora.

    – by @webknjaz

    Related issues and pull requests on GitHub: #759.

  • The requires setting has been removed from tox.ini, which works around the upstream tool bug. This enabled us to re-introduce CI jobs testing against sdist under Python 3.12 and newer – by @webknjaz.

    Related issues and pull requests on GitHub: #764.

  • Updated the version of libssh to the latest release v0.11.3 in the cached manylinux build environment container images – by @Jakuje.

    Related issues and pull requests on GitHub: #765.

  • Changed tests to use more lightweight ECDSA keys to avoid timeouts – by @Jakuje.

    Related issues and pull requests on GitHub: #768.


Released versions

v1.2.2

(2024-06-27)

Bug fixes

  • Downloading files larger than 64kB over SCP no longer fails – by @Jakuje.

    Related issues and pull requests on GitHub: #621.


v1.2.1

(2024-06-27)

Bug fixes

  • Downloading non-existent remote files via SCP no longer crashes the program – by @Jakuje.

    Related issues and pull requests on GitHub: #208, #325, #620.

Packaging updates and notes for downstreams

Contributor-facing changes


v1.2.0.post4

(2024-06-09)

Packaging updates and notes for downstreams

  • Substituting the gh role in source distribution long description has been simplify to stop attempting to make URLs to arbitrary GitHub addresses – by @webknjaz.

    Related commits on GitHub: f4ad1b76.

  • The in-tree PEP 517 build backend’s regular expression has been hotfixed to replace the “project” substitution correctly – by @webknjaz.

    Previously, it was generating a lot of noise instead of a nice description. But not anymore.

    Related issues and pull requests on GitHub: #92752210.


v1.2.0.post2

(2024-06-08)

Packaging updates and notes for downstreams

  • The automation now replaces the “project” RST substitution in the long description and GitHub Discussions/Releases – by @webknjaz.

    Related commits on GitHub: 13374a71.

  • The CI/CD automation has been fixed to include changelog updates into source distribution tarballs – by @webknjaz.

    Related commits on GitHub: 627f718d.


v1.2.0

(2024-06-07)

Bug fixes

  • ansible-pylibssh no longer crashes when received EOF or when channel is not explicitly closed – by @pbrezina.

    Previously, ansible-pylibssh crashed if channel.recv was called and libssh returned SSH_EOF error. It also crashed on some special occasions where channel was not explicitly closed and the session object was garbage-collected first.

    Related issues and pull requests on GitHub: #576.

Features

  • Started exposing the SSH_OPTIONS_PUBLICKEY_ACCEPTED_TYPES and SSH_OPTIONS_HOSTKEYS options publicly – by @Qalthos.

    Related issues and pull requests on GitHub: #527.

  • The request_exec() method was added to the Channel class. It exposes an interface for calling the respective low-level C-API of the underlying libssh library – by @pbrezina.

    Additionally, the following calls to libssh are now available in the same class: request_exec(), send_eof(), request_send_signal() and is_eof which is exposed as a property.

    Related issues and pull requests on GitHub: #576.

Improved documentation

  • Fixed spelling of “Connect” in the Session.connect() docstring – by @donnerhacke.

    Related issues and pull requests on GitHub: #474.

  • Added a tip to the installation guide on how to set compiler flags when installing from source – @webknjaz.

    Related issues and pull requests on GitHub: #499.

  • Fixed the example of invoking remote commands by using Channel.exec_command() in snippets – by @pbrezina.

    Its previously showcased version wasn’t functional.

    Related issues and pull requests on GitHub: #576.

Packaging updates and notes for downstreams

  • A flaw in the logic for copying the project directory into a temporary folder that led to infinite recursion when TMPDIR was set to a project subdirectory path. This was happening in Fedora and its downstream due to the use of pyproject-rpm-macros. It was only reproducible with pip wheel and was not affecting the pyproject-build users.

    – by @hroncok and @webknjaz

    Related commits on GitHub: 89c9b3a.

  • From now on, the published distribution package artifacts for the new releases are signed via Sigstore – by @webknjaz.

    This is happening as a part of the GitHub Actions CI/CD workflow automation and the signatures are uploaded to the corresponding GitHub Release pages.

    Related commits on GitHub: 986988a.

  • The platform-specific macOS wheels are now built using the Python interpreter from https://python.org. They are tagged with macosx_10_9 – by @webknjaz.

    Related issues and pull requests on GitHub: #333.

  • The toml build time dependency has been replaced with tomli – by @webknjaz.

    The tomli distribution is only pulled in under Python versions below 3.11. On 3.11 and higher, the standard library module tomllib is now used instead.

    Related issues and pull requests on GitHub: #501.

  • Started using the built-in setuptools-scm Git archive support under Python 3.7 and higher – @webknjaz.

    Related issues and pull requests on GitHub: #502.

  • Added support for Python 3.12 – by @Qalthos.

    It is now both tested in the CI and is advertised through the Trove classifiers.

    Related issues and pull requests on GitHub: #532.

  • The Cython build time dependency now has the minimum version of 3.0 under Python 3.12 and higher – by @webknjaz.

    The previous versions of Cython are still able to build the project under older Python versions.

    Related issues and pull requests on GitHub: #540.

  • PEP 660 is now enabled – @webknjaz.

    Previously, due to restrictive PEP 517 hook reimports, our in-tree build backend was losing non-PEP 517 hooks implemented in newer versions of setuptools but not the earlier ones. This is now addressed by reexporting everything that setuptools exposes with a wildcard.

    Related issues and pull requests on GitHub: #541.

  • The setuptools-scm build dependency CI pin was updated to 8.1.0 — this version fixes a date parsing incompatibility introduced by Git 2.45.0 (pypa/setuptools_scm#1038, pypa/setuptools_scm#1039) – by @webknjaz.

    Related issues and pull requests on GitHub: #601.

Contributor-facing changes

  • The Changelog page for the tagged release builds on Read The Docs does not attempt showing the draft section anymore – by @webknjaz.

    Related commits on GitHub: 852d259.

  • Adjusted the publishing workflow automation to pre-configure Git before attempting to create a tag when building a source distribution – by @webknjaz.

    Related commits on GitHub: f07296f.

  • The CI configuration for building the macOS platform-specific wheels switched to using cibuildwheel – by @webknjaz.

    Related issues and pull requests on GitHub: #333.

  • The OS-level tox package was upgraded to v3.28.0 in the UBI9 CI runtime – by @Qalthos.

    Related issues and pull requests on GitHub: #461, #473.

  • Fixed spelling of “Connect” in the Session.connect() docstring – by @donnerhacke.

    Related issues and pull requests on GitHub: #474.

  • The Packit CI access to the internet has been restored – by @Qalthos.

    Related issues and pull requests on GitHub: #507.

  • Started building manylinux_2_28 base images for testing and packaging in the CI/CD infrastructure – by @Qalthos.

    Related issues and pull requests on GitHub: #533.

  • Switched back to using Cython’s native plugin for measuring code coverage – by @webknjaz.

    Related issues and pull requests on GitHub: #538.

  • Added separate changelog fragment types for contributor- and downstream-facing patches – by @webknjaz.

    Their corresponding identifiers are contrib and packaging respectively. They are meant to be used for more accurate classification, where one would resort to using misc otherwise.

    Related issues and pull requests on GitHub: #539.

  • PEP 660 is now enabled – @webknjaz.

    This effectively means that the ecosystem-native editable install mode started working properly.

    Related issues and pull requests on GitHub: #541.

  • The duplicated jobs matrices for building manylinux wheels now reside in a single GitHub Actions CI/CD reusable workflow definition.

    @webknjaz

    Related issues and pull requests on GitHub: #559.

  • The duplicated jobs matrices of the text jobs now reside in a single GitHub Actions CI/CD reusable workflow definition.

    @webknjaz

    Related issues and pull requests on GitHub: #560.

  • Fixed the location of release workflow in the Release Guide document – by @Qalthos.

    Related issues and pull requests on GitHub: #565.

  • The setuptools-scm build dependency CI pin was updated to 8.1.0 — this version fixes a date parsing incompatibility introduced by Git 2.45.0 (pypa/setuptools_scm#1039, pypa/setuptools_scm#1038) – by @webknjaz.

    Related issues and pull requests on GitHub: #601.

  • The CI/CD configuration was fixed to allow publishing to PyPI and other targets disregarding the test stage outcome. This used to be a bug in the workflow definition that has now been fixed.

    – by @pbrezina and @webknjaz

    Related issues and pull requests on GitHub: #602.


v1.1.0 (2022-12-05)

Features

  • Started building manylinux wheels with libssh v0.9.6 – by @webknjaz (#441)

Deprecations (removal in next major release)

  • The project stopped being tested under Ubuntu 18.04 VM since GitHub is sunsetting their CI images – by @webknjaz (#381)

Documentation

Miscellaneous

  • Started testing RPM packaging spec with Packit service – by @webknjaz and @TomasTomecek (#227, #246)

  • Removed the remains of Python 2 compatiblity code from the in-tree PEP 517 build backend – by @webknjaz (#377)

  • Fixed removing expandvars from pyproject.toml in an RPM spec – by @webknjaz

    Before this patch, the sed invocation removed entire build-system.requires entry from there, in rare cases but this won’t be happening anymore. (#378)

  • Declared official support of CPython 3.11 – by @Qalthos (#396)

  • Started shipping sdists built with Cython v0.29.32 – by @webknjaz (#399)

  • Started building RPMs with Cython v0.29.32 – by @webknjaz (#402)

  • Added an SSH connection re-try helper to tests – by @webknjaz (#405)

v1.0.0 (2022-09-14)

Features

  • Added password_prompt argument to connect() to override the default prompt of “password:” when using keyboard-interactive authentication – by @Qalthos (#331)

  • Added support for :fd: socket option – by @sabedevops (#343)

Miscellaneous

  • Reworked build scripts to fix manylinux container generation – by @Qalthos (#321)

  • Reenable CI building on s390x – by @Qalthos (#322)

v0.4.0 (2022-04-26)

Bugfixes

  • Improved channel.exec_command to always use a newly created ssh_channel to avoid segfaults on repeated calls – by @Qalthos (#280)

  • Fixed password prompt match in pylibsshext.session.Session.authenticate_interactive() to strip whitespace, check that the prompt only ends with password:, and added a little extra logging – by @dalrrard (#311)

Backward incompatible changes

  • Dropped support for Python 2.7 and 3.5, and marked support for 3.10 – by @Qalthos (#314)

v0.3.0 (2021-11-03)

Bugfixes

  • Changed sftp.sftp_get to write files as bytes rather than assuming files are valid UTF8 – by @Qalthos (#216)

Features

  • Started building platform-specific manylinux2010, manylinux2014 and manylinux_2_24 wheels for AARCH64, ppc64le and s390x architectures as introduced by PEP 599 and PEP 600@webknjaz (#187)

  • Added gssapi-with-mic support for authentication – by @Qalthos (#195)

Documentation

  • Correct a link to the pip upgrade doc in our installation guide – @webknjaz (#225)

Miscellaneous

  • Started building AARCH64 base images with Buildah+Podman in GitHub Actions CI/CD – @webknjaz (#181)

  • Switched using pep517 lib to build CLI – @webknjaz (#199)

  • Restructured the in-tree PEP 517 build backend into multiple submodules moving the entry-point to pep517_backend.hooks that also facilitates extraction of user-defined config_settings passed by the end-user (packager) via the build CLI command – @webknjaz (#200)

  • Updated manylinux build script to build libssh with GSSAPI enabled – @Qalthos (#203)

  • Added an initial RPM spec continuously tested in the CI – @webknjaz (#205)

  • Added additional details when SFTP write errors are raised – by @Qalthos (#216)

  • Made auditwheel only keep one platform tag in the produced wheel names – @webknjaz (#224)

  • Improved manylinux build scripts to expect dual-aliased manylinux tags produced for versions 1/2010/2014 along with their PEP 600 counterparts after auditwheel repair@webknjaz (#226)

  • Enabled self-test checks in the RPM spec for Fedora – @webknjaz (#228)

  • Enabled self-test checks in the RPM spec for CentOS – @webknjaz (#235)

  • Enabled self-test checks in the RPM spec for RHEL – @webknjaz (#236)

  • Added NAME = "VALUE" to flake8-eradicate whitelist to work around test false positive introduced in flake8-eradicate 1.1.0 – by @Qalthos (#258)

  • Stopped testing pylibssh binary wheels under Ubuntu 16.04 in GitHub Actions CI/CD because it is EOL now – @webknjaz (#260)

  • Fixed failing fast on problems with rpmbuild in GitHub Actions CI/CD under Fedora – @webknjaz (#261)

  • Declare python3-pip a build dependency under Fedora fixing the RPM creation job in GitHub Actions CI/CD under Fedora – @webknjaz (#262)

  • Replaced git protocols in pre-commit config with https now that GitHub has turned off git protocol access – @Qalthos (#266)

v0.2.0 (2021-03-01)

Bugfixes

  • Fixed undefined symbol: ssh_disconnect and related issues when building on certain distros – by @Qalthos (#63, #153, #158)

  • Fixed "Negative size passed to PyBytes_FromStringAndSize" when ssh_channel_read_nonblocking fails – by @Qalthos (#168)

Features

Documentation

Miscellaneous

v0.1.0 (2020-08-12)

Bugfixes

  • Enhanced sftp error handling code to match with libssh error messages – by @ganeshrn (#27)

  • Fixed session timeout issue, the data type of timeout is expected by ssh_options_set is of type long int – by @ganeshrn (#46)

  • Fixed sftp file get issue. On py2 The file write() method returns None on py2 if bytes are written to file successfully, whereas on py3 it returns total number of bytes written to file. Added a fix to check for the number of bytes written only in the case when write() does not return None – by @ganeshrn (#58)

  • Fixed double close issue, added logic to free the channel allocated memory within __dealloc__() – by @ganeshrn (#113)

Features

  • Added cython extension for libssh client API’s initial commit – by @ganeshrn (#1)

  • Added proxycommand support for session and update session exeception to LibsshSessionException – by @ganeshrn (#10)

  • Added support for host key checking with authentication – by @ganeshrn (#15)

  • Changed pylibssh dir to pylibsshext to avoid ns collision – by @ganeshrn (#25)

  • Added sftp get functionality to fetch file from remote host – by @amolkahat (#26)

  • Added support to receive bulk response for remote shell – by @ganeshrn (#40)

  • Added the support for keyboard-authentication method – by @Qalthos (#105)

Backward incompatible changes

  • Updated the package name to ansible-pylibssh to reflect that the library only intends to implement a set of APIs that are necessary to implement an Ansible connection plugin – by @ganeshrn (#1)

Documentation

Miscellaneous

  • Updated requirements file to replace requirements.txt with requirements-build.in – by @akasurde (#14)

  • Made tox’s main env pick up the in-tree PEP 517 build backend – by @webknjaz (#72)

  • Refactored sphinx RST parsing in towncrier extension – by @ewjoachim (#119)

  • Hotfixed the directive in the in-tree sphinx extension to always trigger the changelog document rebuilds so that it’d pick up any changelog fragments from disk – by @webknjaz (#120)

  • Turned the Townrier fragments README doc title into subtitle – by @webknjaz

    The effect is that it doesn’t show up in the side bar as an individual item anymore. (#125)

  • Integrated Markdown support into docs via the MyST parser – by @webknjaz (#126)

  • Switched the builder on Read the Docs to dirhtml so it now generates a dir-based URL layout for the website – by @webknjaz (#127)

  • Enabled sphinx.ext.autosectionlabel Sphinx extension to automatically generate reference targets for document sections that can be linked against using :ref: – by @webknjaz (#128)