PEP 715 – Disabling bdist_egg distribution uploads on PyPI
- William Woodruff <william at yossarian.net>
- Donald Stufft <donald at stufft.io>
- Donald Stufft <donald at stufft.io>
- Discourse thread
- Standards Track
- Discourse message
This PEP recommends deprecating and then disabling new uploads of the
bdist_egg distribution type on PyPI. In a parallel move, this PEP recommends
deprecating and then disabling new uploads of distribution filenames that have
After this PEP, PyPI will only accept new uploads of the
bdist_wheel types, corresponding to files with
.whl suffixes respectively.
This PEP does not recommend removing or otherwise affecting any previously
bdist_egg distributions or files with the
The groundwork for this proposal was established with PEP 527, which proposed deprecating and eventually removing upload support for a handful of un(der)used file extensions and distribution types.
In particular, PEP 527 proposed the removal of the
types, as well as the
.tbz file extensions on distribution filenames.
PEP 527 was fully enacted with PR #7529 to Warehouse, which was merged on 13 April 2020.
bdist_egg filetype identifies distributions in the
egg format. The
egg format was introduced by setuptools in 2004 and is roughly equivalent
in functionality to the
first introduced by PEP 427 in 2012
as the standardized format
for built distributions.
Despite its longevity, the egg format has had limited adoption on PyPI. Some observations from that issue:
- In the month of May 2023,
bdist_egguploads accounted for 0.2% of all distribution uploads to PyPI;
--eggoption in 2016;
setuptoolshas considered egg support deprecated since 2019;
buildonly supports the
Given the above, this PEP proposes the removal of the
under the same justifications presented in PEP 527, namely:
- Egg distributions are of limited use to the broader ecosystem and therefore represent a non-reciprocal maintenance burden;
- Having an additional built distribution format is confusing to end users, who may mistakenly pick it over the wheel format;
This PEP additionally offers an argument for removal rooted in standardization and duplication: the egg format is not standardized by any PEP or other community standard, and overlaps heavily with its standardized and well-supported alternative (wheel).
.egg file extension
.egg file extension is used exclusively for distributions of the
bdist_egg format. As such, it serves no purpose in a scenario where
PyPI disables new distribution uploads for
This PEP does NOT propose removing any existing files from PyPI, only disallowing new ones from being uploaded.
PyPI will provide a deprecation period of one month. At the beginning of the deprecation period, maintainers of projects that have uploaded one or more egg distributions since 1 Jan 2023 will receive a one-time email informing them of the upcoming end of support for egg distribution uploads.
During the deprecation period, users will continue to be allowed to upload egg distributions to new and existing projects. Uploading an egg distribution during this period will also send all maintainers of the project a similar email as above, reminding them of the upcoming end of support.
After the deprecation period, support for uploading egg distributions will cease to exist on PyPI.
The removal process above was based on that of PEP 527, with the following changes:
- All projects will be continue to be allowed to upload eggs during the deprecation period, not just those that have done so previously.
- Uploading an egg during the deprecation period will also trigger an email to maintainers, in addition to the one-time email at the beginning.
As noted in the rationale section, this PEP is expected to have no impact on the overwhelming majority of PyPI users and projects, and there has been substantial community coordination over the past 1 1/2 years to minimize the impact on the few last use cases.
This PEP does NOT propose the removal of any egg distributions that have already been uploaded to PyPI. All previously uploaded egg distributions will remain downloadable, ensuring that existing users will continue to be able to download them.
This PEP uses the removal process documented above, which specifies a deprecation period of 1 month for projects that have previously uploaded egg distributions to PyPI.
After the end of the deprecation period, support for uploading new egg distributions will cease to exist on PyPI.
This PEP does not identify any positive or negative security implications associated with removing upload support for egg distributions.
How To Teach This
As part of the removal process, PyPI will send emails to all maintainers of projects that have previously uploaded egg distributions in 2023.
Additionally, PyPI will write a post on the PyPI blog that publicly announces the deprecation period’s start and end.
This document is placed in the public domain or under the CC0-1.0-Universal license, whichever is more permissive.
Last modified: 2023-09-09 17:39:29 GMT