fix(datetime): selecting today with multiple date select now works

[liamdebeasi]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
  • Some docs updates need to be made in the ionic-docs repo, in a separate PR. See the contributing guide for details.
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Sean noted that https://github.com/ionic-team/ionic-framework/actions/runs/2776107067 was failing due to an unrelated test. Upon further investigation it was determined that selecting today's date with multiple="true" does not work on the first click.

When we call setActiveParts on clicking the day button, we pass in isActive. Presumably this was done to ensure that we can toggle dates:

ionic-framework/core/src/components/datetime/datetime.tsx

Line 1932 in 61e4ffe

isActive

. Unfortunately,isActive doesn’t necessarily mean the date is selected. It means it is either selected or highlighted as “today’s date”.

Future work should clean this up so it is easier to reason about.

What is the new behavior?

• We now pass in isActive && highlightActiveParts to differentiate between a today's date that is selected vs today's date that just has the outline.

Does this introduce a breaking change?

• Yes
• No

Other information