PEP 843: Export Statement for DRY Re-exports

[NeilGirdhar]

Basic requirements (all PEP Types)

• Read and followed PEP 1 & PEP 12
• File created from the latest PEP template
• PEP has next available number, & set in filename (pep-NNNN.rst), PR title (PEP 123: <Title of PEP>) and PEP header
  • Tip: find the next available number with pepotron — run uvx pepotron next (or pipx install pepotron then pep next)
• Title clearly, accurately and concisely describes the content in 79 characters or less
• Core dev/PEP editor listed as Author or Sponsor, and formally confirmed their approval
• Author, Status (Draft), Type and Created headers filled out correctly
• PEP-Delegate, Topic, Requires and Replaces headers completed if appropriate
• Required sections included
  • Abstract (first section)
  • Copyright (last section; exact wording from template required)
• Code is well-formatted (PEP 7/PEP 8) and is in code blocks, with the right lexer names if non-Python
• PEP builds with no warnings, pre-commit checks pass and content displays as intended in the rendered HTML
• Authors/sponsor added to .github/CODEOWNERS for the PEP

Standards Track requirements

• PEP topic discussed in a suitable venue with general agreement that a PEP is appropriate
• Suggested sections included (unless not applicable)
  • Motivation
  • Specification
  • Rationale
  • Backwards Compatibility
  • Security Implications
  • How to Teach This
  • Reference Implementation
  • Rejected Ideas
  • Open Issues
  • Acknowledgements
  • Footnotes
  • Change History
• Python-Version set to valid (pre-beta) future Python version, if relevant
• Any project stated in the PEP as supporting/endorsing/benefiting from the PEP formally confirmed such
• Right before or after initial merging, PEP discussion thread created and linked to in Discussions-To and Post-History

[read-the-docs-community]

Documentation build overview

📚 pep-previews | 🛠️ Build #34175771 | 📁 Comparing 8ea189a against latest (0475dc3)

  🔍 Preview build  

25 files changed · + 4 added · ± 21 modified

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• pep-0839/index.html
• pep-0841/index.html
• pep-0843/index.html
• pep-0844/index.html

± Modified

• index.html
• numerical/index.html
• pep-0000/index.html
• pep-0001/index.html
• pep-0345/index.html
• pep-0444/index.html
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[hugovk]

Please add the new PEP checklist to the top post, and start checking things off:

https://github.com/python/peps/blob/main/.github/PULL_REQUEST_TEMPLATE/Add%20a%20new%20PEP.md

[vstinner]

It would be better to get a sponsor for your PEP and merge the PR before mentioning your PEP on a public discussion: https://discuss.python.org/t/export-statement-for-dry-re-exports/108444.

[NeilGirdhar]

It would be better to get a sponsor for your PEP and merge the PR before mentioning your PEP on a public discussion: https://discuss.python.org/t/export-statement-for-dry-re-exports/108444.

Fair point, I'm definitely looking for a sponsor!

[warsaw]

I can't find the comment in the review now, but via email I saw this comment from @ZeroIntensity:

You should mark this as Replaces: 842. If this PEP is accepted, PEP 842 will be marked as "Superseded".

I don't think that's quite right though. Replaces and Superseded are really there to relate a new PEP that replaces an existing approved PEP. Since 842 isn't approved (yet), I wouldn't expect those headers to be added to this one.

Of 842, 843, and 844, I would expect whatever combination gets approved would just be marked Approved and the others (if any) would be marked Rejected. There's nothing to replace or supersede.

Maybe we need to clarify this in PEP 12?

[ZeroIntensity]

Yes, Jelle disagreed with me as well.

I still think Replaces/Superseded is the best choice for 842 if we merge this, because this PEP is just a subset of 842. If it becomes clear that 842 is doing too much, then I'll withdraw it and sponsor this -- hence why I think it "replaces" 842.

[hugovk]

Yeah, let's be careful about sticking to the boring old processes for stuff like this, better to have a broader discussion elsewhere if we want to change it.

PEP 12 says:

Add a Replaces header if your PEP obsoletes an earlier PEP. The value of this header is the number of the PEP that your new PEP is replacing. Only add this header if the older PEP is in “final” form, i.e. is either Accepted, Final, or Rejected. You aren’t replacing an older open PEP if you’re submitting a competing idea.

(Now I remember I've also suggested Replaced/Superseded-by on a non-final PEP before, so it's good the authors didn't take me up on the idea! 😅)

If PEP 842 is withdrawn: a withdrawal notice at the top is useful, and this can include some prose with reasoning and link to 843.

[ZeroIntensity]

Given the accumulating contention surrounding PEP 842, I would like to confirm my sponsorship of PEP 843.

[gvanrossum]

Please don’t force-push. It will be squashed when merged.

[ZeroIntensity]

This generally looks good. Let's try to get this up soon, since some people have been confused about why PEP 844 references a PEP that doesn't seem to exist.

[ZeroIntensity]

Please also fix the merge conflicts.

[ZeroIntensity]

LGTM. If you're ready to start the discussion, I can merge this.

[NeilGirdhar]

Sounds great, thanks for speedy review

[ZeroIntensity]

If any of the other reviewers see something they'd like changed, feel free to send a follow-up.