RLS: 2.0

[simonjayhawkins]

Tracking issue for the 2.0 release.

Note: pandas 2.0 is the next major release in the pandas semver-like release cycle and different from some historical discussion about the pandas future also named pandas 2.

Blockers

• Datetime parsing (PDEP-4): allow mixture of ISO formatted strings #50939

Scheduled

Feb 2023

References

• Milestone: https://github.com/pandas-dev/pandas/milestone/42
• Deprecations list: DEPR: log of deprecations in 1.x (to be removed in 2.0) #30228
• Breaking changes: API: Breaking Changes in 3.0 (without deprecations) #44823

[simonjayhawkins]

we don't have a master tracker for deprecations that should be in a released pandas before we release 2.0.

There are currently 91 issues labeled deprecate https://github.com/pandas-dev/pandas/issues?q=is%3Aopen+is%3Aissue+label%3ADeprecate, so need to start whittling this list down.

[jbrockmendel]

A few things on my radar screen that I think need to change in 2.0, which in many cases means deprecating in 1.5:

• BUG/API: DataFrame.iloc[:, foo] = bar inplaceness? #44353 -> DEPR: df.iloc[:, foo] = bar attempt to set inplace #45333
• API: make CategoricalIndex._concat consistent with pd.concat #41626
• DEPR: inplace dtype-changing methods on Categorical #37643

[mroeschke]

we don't have a master tracker for deprecations that should be in a released pandas before we release 2.0.

There are currently 91 issues labeled deprecate https://github.com/pandas-dev/pandas/issues?q=is%3Aopen+is%3Aissue+label%3ADeprecate, so need to start whittling this list down.

My interpretation is that issues labeled deprecate doesn't necessarily mean they need to all be decided upon (yes & implemented or no) by 2.0; just that they are up for consideration anytime.

[rhshadrach]

Agreed @mroeschke. I've been tagging deprecation issues where the conversation makes it clear there is no consensus as "Needs Discussion". There are currently only 46 issues that are tagged deprecation but not needs discussion. Maybe it'd be reasonable to whittle down this list by either (a) implementing or (b) tagging as needs discussion.

https://github.com/pandas-dev/pandas/issues?q=is%3Aopen+is%3Aissue+label%3ADeprecate+-label%3A%22Needs+Discussion%22

[lithomas1]

@pandas-dev/pandas-core Are there any objections for the next release to be 2.0?

[phofl]

I think the agreement on the august call was to wait with the final decision till 1.5.1 is out in case anything unexpected happens

[mroeschke]

As mentioned by @lithomas1 on Slack, do folks think we should push a 2.0.0.dev0 tag now that 2.0 is agreed to be the new version? The reasoning is to help downstream nightly/main users pin as we start enforcing deprecations.

[datapythonista]

I updated this issue description with the list of blockers for 2.0 I'm aware of (the known deprecations, plus a 1.4 deprecation that was not track or enforced). If there are other blockers to be considered, it'd be good to add them to the list before the call next week, so we can discuss them.

[mroeschke]

Updated the issue description after the outcome of the 2023-01-11 dev meeting (only blocker was the Int/Uint/FloatIndex removal)

[mroeschke]

Updated the issue description after the outcome of the 2023-02-08 dev meeting

@datapythonista would you still be willing to do a 2.0rc release sometime next week assuming the above PRs get merged? @lithomas1 expressed willingness to do a release if you are unable