Twenty Fourteen, Fifteen, Seventeen: allow category display in post preview even when only 1 category

[lancewillett]

Steps to repeat

1. Using a site with only the category, "Uncategorized, switch to Twenty Fourteen or Twenty Fifteen.
2. Create new post draft, and in the post meta box for Categories add a new category.
3. Save (don't publish), and Preview.
4. The new category will not be in the preview.
5. If you publish, the end result shows two categories, as expected.

What I expected
For the post preview to show the 2nd category I added, after saving the post.

What happened instead
The category is not shown in the preview. And because of how twentyfifteen_categorized_blog() returns false for 1 or fewer categories, in this case it won't show the new category.

Screenshots
Attached.

Note: this occurs in Twenty Sixteen as well, bug logged in GitHub: ​https://github.com/WordPress/twentysixteen/pull/492

[SergeyBiryukov]

Replying to lancewillett:

Note: this occurs in Twenty Sixteen as well (but it's not in the develop src repo that I can see.)

Per comment:1:ticket:38468, Twenty Sixteen issues should be reported on GitHub: ​https://github.com/WordPress/twentysixteen/issues.

Looking at Twenty Seventeen though, seems like it would also be affected?

[lancewillett]

Looking at Twenty Seventeen though, seems like it would also be affected?

Good point, I missed it. Will add a patch here shortly.

Twenty Sixteen pull request added here: ​https://github.com/WordPress/twentysixteen/pull/492 — thanks for the reminder on that.

[davidakennedy]

Great find @lancewillett! I tested and can confirm the bug. I also tested the patch and it works well. I think this one should be good to go.

[davidakennedy]

In 40023:

Bundled Themes: Allow category display in post preview even when only one category

The category is not shown in the preview. And because of how themename_categorized_blog() function in each theme returns false for 1 or fewer categories, and in this case it won't show the new category.

The patch uses is_preview() to fix that in Twenty Fourteen, Fifteen and Seventeen.

Props lancewillett.

Fixes #39531.

[lancewillett]

@davidakennedy Can you review and merge my Twenty Sixteen patch also? ​https://github.com/WordPress/twentysixteen/pull/492

[SergeyBiryukov]

There's a consensus on merging Twenty Sixteen into core SVN in #36497, reopening to make sure it gets the fix as well.

[irebu]

i don't know why needed twentyfifteen_categorized_blog(), twentysexteen_categorized_blog(), twentyseventeen_categorized_blog(), i will delete it from tamplate, or change inside function get_categories(array(...)) to get_the_category()

[davidakennedy]

Allow category display in post preview even when only 1 category for Twenty Sixteen

[davidakennedy]

I ported over the patch from Lance on ​https://github.com/WordPress/twentysixteen/pull/492/files since Twenty Sixteen is no longer maintained on GitHub. Make sure @lancewillett gets props.

[SergeyBiryukov]

In 40908:

Twenty Sixteen: Allow category display in post preview even when there is only one category.

Props lancewillett, davidakennedy.
Fixes #39531.

[pento]

This seems to be a fairly low impact bug, so I'm moving it to 4.9. It doesn't need to be backported to the 4.8 branch.