Previous Work

The groundwork for this proposal was established withPEP 527, whichproposed deprecating and eventually removing upload support for a handfulof un(der)used file extensions and distribution types.

In particular,PEP 527 proposed the removal of thebdist_dumb,bdist_rpm,bdist_dmg,bdist_msi, andbdist_wininst distributiontypes, as well as the.tar,.tar.bz2,.tar.xz,.tar.Z,.tgz, and.tbz file extensions on distribution filenames.

PEP 527 was fully enacted withPR #7529 to Warehouse,which was merged on 13 April 2020.

Thebdist_egg format

Thebdist_egg filetype identifies distributions in theegg format. Theegg format was introduced by setuptools in 2004 and is roughly equivalentin functionality to thewheel formatfirst introduced byPEP 427 in 2012asthe standardized formatforbuilt distributions.

Despite its longevity, the egg format has hadlimited adoption on PyPI.Some observations from that issue:

• In the month of May 2023,bdist_egg uploads accounted for 0.2% of alldistribution uploads to PyPI;
• pip deprecated its--egg option in 2016;
• setuptools has considered egg support deprecated since 2019;
• build only supports thesdist andbdist_wheel filetypes.

Given the above, this PEP proposes the removal of thebdist_egg formatunder the same justifications presented inPEP 527, namely:

• Egg distributions are of limited use to the broader ecosystem andtherefore represent a non-reciprocal maintenance burden;
• Having an additional built distribution formatis confusing to end users, who maymistakenly pick it over the wheel format;

This PEPadditionally offers an argument for removal rooted instandardization and duplication: the egg format is not standardized by anyPEP or other community standard, and overlaps heavily with its standardizedand well-supported alternative (wheel).

The.egg file extension

The.egg file extension is used exclusively for distributions of thebdist_egg format. As such, it serves no purpose in a scenario wherePyPI disables new distribution uploads forbdist_egg distributions.

Prior Art

The removal process above was based on that ofPEP 527, with the followingchanges:

• All projects will be continue to be allowed to upload eggsduring the deprecation period, not just those that have done so previously.
• Uploading an egg during the deprecation period will also trigger an emailto maintainers, in addition to the one-time email at the beginning.

Limited Impact

As noted in the rationale section, this PEP is expected to have no impacton the overwhelming majority of PyPI users and projects, and there has beensubstantial community coordinationover the past 1 1/2 years to minimize the impact on the few last use cases.

Hosted Files

This PEP doesNOT propose the removal of any egg distributions that havealready been uploaded to PyPI. All previously uploaded egg distributions willremain downloadable, ensuring that existing users will continue to be ableto download them.

Deprecation Period

This PEP uses the removal process documented above, which specifiesa deprecation period of 1 month for projects that have previously uploadedegg distributions to PyPI.

After the end of the deprecation period, support for uploading new eggdistributions will cease to exist on PyPI.