Accessibility: Media: Replace `@` with `at` in the displayed date format.

The `@` symbol makes sense in the context of email addresses, but does not have a universal meaning in the context of dates.

Props audrasjb, afercia.
Fixes #47893.

Accessibility: Comments: Replace `@` with `at` in the displayed date format.

The `@` symbol makes sense in the context of email addresses, but does not have a universal meaning in the context of dates.

Props birgire, afercia, audrasjb, SergeyBiryukov.
Fixes #47893.

Accessibility: Posts, Post Types: Replace `@` with `at` in the displayed date format.

The `@` symbol makes sense in the context of email addresses, but does not have a universal meaning in the context of dates.

Props birgire, afercia, audrasjb, SergeyBiryukov.
Fixes #47832.

Docs: Fix typo in `WP_Hook::resort_active_iterations()` description.

Props itowhid06.
Fixes #47999.

Upload: Reset the temp upload reference in Plupload when the file is not an image.

See #47872.

Posts, Post Types: Revert [46079] pending test failure investigation.

See #47824.

Posts, Post Types: Avoid a PHP warning when `the_content()` is called outside of the loop.

Fixes #47824.

Fix "white spaces at end of line" in docblock (IDE) woes after [46077].

See #32437.

Media: Improve handling of cases where an uploaded image matches exactly a defined intermediate size. In most of these cases the original image has been edited by the user and is "web ready", there is no need for an identical intermediate image.

Introduces the `wp_image_resize_identical_dimensions` filter so plugins and themes can determine whether a new image with identical dimensions should be created, defaults to false.

Props wpdennis, HKandulla, galbaras, azaozz.
See #32437.

Media: Add handling for "BIG" images. When the users upload a big image, typically a photo, scale it down to make it suitable for web use. Then use the scaled image as the "full" size, and keep the originally uploaded image for creating high quality sub-sizes in the future and in case the users want to download it later.

Introduces `wp_get_original_image_path()` that retrieves the path to the originally uploaded image in all cases, and `big_image_size_threshold` filter to set the pixel value above which images will be scaled. The same value is used as max-width and max-height when scaling.

See #47873.

Uploads: Improve the error message shown when all attempts to create image sub-sizes fail.

Props afercia.
See #47872.

Remove the extra call for wp-sanitize from the script loader.

Fixes #47986

Upgrade/Install: Escape the `%` in `width="100%"` in a `printf()` call in `Plugin_Upgrader_Skin::after()`.

Props afragen.
Fixes #47989.

Docs: Improve documentation for `do_meta_boxes` action.

Props felipeelia, killua99, SergeyBiryukov.
Fixes #46542.

REST API: Mark `WP_REST_Users_Controller::update_current_item()` and `::delete_current_item()` as public.

Props dkarfa.
Fixes #47967.

Docs: Remove extra spaces in various REST API DocBlocks.

See #47110.

Docs: Correct DocBlocks for `WP_REST_Posts_Controller::get_available_actions()` and `WP_REST_Revisions_Controller::get_parent()`.

Props dkarfa.
Fixes #47966.

Fix (unrelated) test after [46066].

See #43524.

Media: Add two new intermediate image sizes, 1536px and 2048px. They are meant to enhance the way WordPress displays images on the front-end on larger, high-density devices. They make it possible to generate more suitable `srcset` and `sizes` attributes, and not use the original, often non-optimized image.

Also change the default `max_srcset_image_width` value to match the new max size.

Props pierlo, azaozz.
See #43524.

Widgets: Fix "jumpiness" when reordering widgets by dragging them.

Props ketanumretiya030, mukesh27, andraganescu, audrasjb.
Fixes #46941.

Coding Standards: Fix WPCS issue in [45990].

Fix for URL sanitization that can lead to cross-site scripting (XSS) attacks.

Props irsdl, sstoqnov, whyisjake.

Improve handling the existing `rel` attribute in `wp_rel_nofollow_callback()`.

Props xknown, sstoqnov.

Update wp.a11y.speak() to sanitize HTML before display.

Props iandunn, adamsilverstein, sstoqnov, peterwilsoncc

Improve URL validation in `wp_validate_redirect()`.

Props vortfu, whyisjake, peterwilsoncc.

Bundled Theme: Twenty Nineteen: Use human-friendly color names.

For better accessibility, the Primary and Secondary theme colors have now more understandable names.
Changes the names "Primary" and "Secondary" to "Blue" and "Dark Blue". Fallbacks to the `hex` color codes when the theme is set to use a custom Primary color.

Props kjellr, aduth, audrasjb.
Fixes #46698.

Bundled Theme: Twenty Nineteen: Fix the nesting of the `main` element.

The `main` element must not appear as a descendant of the `section` element. Correct markup is the first requirement to make user agents and assistive technologies work properly.

Changes the `<section>` element that was wrapping the `<main>` element to a `<div>`.

Props albertomake, ryelle, desrosj, ianbelanger, audrasjb.
Fixes #47066.

Escape the output in `wp_ajax_upload_attachment()`.

Props whyisjake, sstoqnov.

Remove _convert_urlencoded_to_entities() from the get_the_content() callback.

Props vortfu, whyisjake, peterwilsoncc

Uploads: After an image is uploaded and PHP times out or runs out of memory during post-processing (the server response is HTTP 500 error), try to resize it three more times. Then, if all attempts fail, do a cleanup of any sub-sizes that may have been created and show an error message asking the user to scale the image and upload it again.

See #47872.

I18N: Fix typo in a function name in [45932].

See #44360.

I18N: Capitalize translator comments consistently, add trailing punctuation.

Includes minor code layout fixes.

See #44360.

Accessibility: Improve focus styles for legacy modal dialogs powered by jQuery UI.

Fixes #47944.

Accessibility: Audit usage of abbreviations.

Title attributes on abbreviations are only available to a minority of users. The
best option is to avoid unnecessary abbreviations when possible. In the other cases,
use an `<abbr>` element (which provides a hint to user agents on how to announce
and display the abbreviation) and provide an expansion in plain text on first use.

- `readme.html`: improves abbreviations and removes unnecessary `title` attributes
- options-general: removes unnecessary abbreviations and improves the remaining ones
- customizer schedule changeset date: removes unnecessary abbreviations and improves the remaining ones
- posts table date: uses a `span` element instead of an `abbr` element because this is not an abbreviation

Fixes #46980.

Formatting: Improve accuracy of `force_balance_tags()` and add support for custom element tags.

This changeset includes a major iteration on the regular expression used to balance tags, with comprehensive test coverage to ensure that all scenarios are supported or unsupported as expected.

Props dmsnell, westonruter, birgire.
Fixes #47014.

#43590: Use robots meta tag to better discourage search engines.

This changes the "discourage search engines" option to output a `noindex, nofollow` robots meta tag. `Disallow: /` is removed from the `robots.txt` to allow search engines to discover they are requested not to index the site.

Disallowing search engines from accessing a site in the `robots.txt` file can result in search engines listing a site with a fragment (a listing without content).

Props donmhico, jonoaldersonwp.
Fixes #43590.

I18N: Split translatable strings located on the same line preceded with a translator comment, where the first string needs that comment, but the second does not.

Props johnbillion.
See #44360.

I18N: Improve translator comments.

* Add missing translator comments.
* Fix placement of some translator comments. Translator comments should be on the line directly above the line containing the translation function call for optimal compatibility with various `.pot` file generation tools. The CS auto-fixing, which changed some inconsistent function calls to multi-line function calls, is part of the reason why this was no longer the case for a select group of translator comments.

Includes minor code layout fixes.

Polyglots, rejoice! All WordPress core files now have translator comments for all strings with placeholders!

Props jrf, subrataemfluence, GaryJ, webdados, Dency, swissspidy, alvarogois, marcomartins, mihaiiceyro, vladwtz, niq1982, flipkeijzer, michielatyoast, chandrapatel, thrijith, joshuanoyce, FesoVik, tessak22, bhaktirajdev, cleancoded, dhavalkasvala, garrett-eclipse, bibliofille, socalchristina, priyankkpatel, 5hel2l2y, adamsilverstein, JeffPaul, pierlo, SergeyBiryukov.
Fixes #44360.

Accessibility: Add a default title for the media modal dialog.

Makes sure the media modal dialog `h1` heading isn't empty when custom media frames don't set a title. This is particularly important now that the media modal is an ARIA dialog, as the title is referenced by an `aria-labelledby` attribute to properly label the dialog.

Props donmhico, audrasjb.
Fixes #47612.

Docs: Improve documentation for `auth_redirect()`.

Props atachibana.
Fixes #47956.

Twenty Nineteen: Remove unused jQuery argument passed to an IIFE that accepts no arguments.

Props Christian1012, hareesh-pillai.
Fixes #40333.

Twenty Seventeen: Remove unused jQuery argument passed to an IIFE that accepts no arguments.

Props Christian1012, hareesh-pillai.
See #40333.

Twenty Nineteen: Correct file name in JS DocBlocks.

See #47110.

Twenty Nineteen: Improve compatibility with custom colors in the separator block.

Props kjellr.
Fixes #47811.

Twenty Nineteen: Remove Baskerville Old Face from the font stack due to several shortcomings:

* Being difficult to read due to its mix of thin and thick strokes.
* Having poor language/extended character support.
* Not having other weights/styles (bold, italic, etc) and relying on browser approximations of those variants.

The next fonts down the stack (Garamond and Times) are more properly aligned to the appearance of the top-level serif font in the stack (Hoefler Text), and work better in its place.

Props kjellr, Rarst, justintadlock.
Fixes #45881.

Comments: In AJAX response when deleting a comment, account for ` ` as a thousands separator in `total_items_i18n` and `total_pages_i18n` numbers.

Props denisco, SergeyBiryukov.
Fixes #47953.

Docs: Simplify `get_plugin_data()` and `get_file_data()` description.

See #47110.

Docs: Update plugin headers example in `get_plugin_data()` to clarify that `Version` is not a required field.

Props casiepa.
See #47110, #meta4707.

Docs: Correct and improve inline docs relating to caching, terms, meta, and some misc tweaks.

See #47110

Date/Time: Restore the previous behavior of `date_i18n()` where invalid input would result in current time.

Make `wp_date()` return `false` on invalid timestamp input, for consistency with upstream PHP `date()` function.

Props Rarst.
Fixes #28636.

I18N: Add missing translator comment in help text on Reading Settings screen.

Props garrett-eclipse.
See #46708.

Administration: Add a note to "For each post in a feed, include [Full text / Summary]" option that how content is displayed in browsers depends on the theme.

Add a documentation link to learn more about feeds.

Props JarretC, SergeyBiryukov, pento, talldanwp, dinhtungdu, noisysocks, tobifjellner.
Fixes #46708.

Date/Time: Update XML-RPC tests for invalid date input to account for a more consistent `mysql2date()` error handling in [45908].

The tests were meant to check for the lack of a fatal error in case of invalid date input, not specifically mark a particular outcome as the correct one.

Props Rarst.
Fixes #28992.

Multisite: Improve performance by caching not found lookups for sites and networks.

With this change, the result of a site or network lookup by ID will be cached even if the ID does not exist. When a new site or network is created, the cache for the respective new ID is cleared.

Props mnelson4, nielsdeblaauw.
Fixes #42251.

Administration: Output valid HTML when `wp_die()` is called.

To better support HTML and string calls to `wp_die()` without
outputting invalid HTML, wraps error messages in `<div>` rather than `<p>`.

Adds `.wp-die-message` CSS class for styling.

Props dinhtungdu, jeremyfelt, audrasjb, SergeyBiryukov, afercia, audrasjb, noisysocks.
Fixes #47580.

Date/Time: Revamp `mysql2date()` to use `wp_date()` and handle invalid input in a consistent manner.

Add unit tests, improve documentation.

Props Rarst, pbearne.
Fixes #28992.

Coding Standards: Fix WPCS issue in [45906].

See #45322.

XML-RPC: Make sure editing a draft post with `wp.editPost` does not unintentionally cause its published date to be set.

Props redsweater.
Fixes #45322.

Site Health: Merge two similar strings explaining what drop-in plugins are.

Props garrett-eclipse, ramiy, Clorith.
Fixes #47247.

Site Health: Standardize on `SELECT VERSION()` query for checking the database server version, due to the MariaDB version declaration potentially causing issues in production environments.

Partially reverts [45691].

Props Clorith.
Fixes #47738.

REST API: Only cast scalar types to string when comparing new & old meta values.

Newly-supported array and object meta types should not be cast to strings.

Props TimothyBlynJacobs, caercam.
Fixes #47928.

Date/Time: Correct delta comparison in `test_should_return_wp_timestamp()`.

See #25768.

Date/Time: Introduce `wp_date()` to retrieve the date in localized format.

Convert `date_i18n()` into a wrapper for `wp_date()`.

`wp_date()` is intended as a replacement for `date_i18n()` without legacy quirks in it. It accepts a true Unix timestamp (not summed with timezone offset) and an arbitrary timezone.

Props Rarst, mboynes, MikeHansenMe, rmccue, nacin.
Fixes #28636.

Date/Time: Remove the last remaining `current_time( 'timestamp' )` instance in `wp_post_revision_title_expanded()`.

Timestamps don't carry any timezone information, using `$revision->post_modified_gmt` simplifies the logic.

Props Rarst.
See #40657.

Docs: Clarify that `$name` and `$value` parameters of `set_user_setting()` can contain hyphens.

Props tmatsuur.
Fixes #47938.

Docs: Remove a clarification from `do_robots()` description that doesn't really clarify anything.

See #47110.

Twenty Nineteen: Make sure center-aligned images in columns do not break beyond the column boundaries.

Props kjellr.
Fixes #47937.

Twenty Nineteen: Update `style-rtl.css` after [45773].

See #47850.

Docs: Reference `WP_Term_Query::__construct()` in `wp_list_categories()` DocBlock for additional accepted arguments.

Clarify that `wp_dropdown_categories()` always returns a string, regardless of the `echo` parameter.

See #47896, #47110.

Taxonomy: Standardize docs for `wp_list_categories()`.

Many of the parameters historically documented on this function are merely
passed through to `get_categories()` and its underlying functions. In order to
avoid unnecessary duplication of function arguments, we remove documentation of
these parameters, and replace it with reference to the wrapped functions.

Parameters that receive special treatment or are otherwise changed before
being passed through continue to be documented as part of `wp_list_categories()`.

Props audrasjb, itowhid06, birgire.
Fixes #47896.

Taxonomy: Fix unique-slug check for terms with parents.

`wp_unique_term_slug()` appends numeric suffixes when the requested slug is
already in use by a sibling term. Changes introduced in [32837] inadvertently
caused this suffixing to be skipped in cases where the requested slug is
suffixed with the parent slug, so that it became possible to have two terms
`childslug-parentslug` underneath to the same `parentslug`. We fix this
regression by ensuring that the numeric-suffix routine runs in all cases.

Props yashar_hv, saskak, dlh.
Fixes #46431.

Docs: Improve and update the description of `multi_resize()` to explain changes and expected use.

See #40439.

Menus: In `wp_setup_nav_menu_item()` and `Walker_Nav_Menu_Edit::start_el()`, check if the post or term associated with the menu item still exists to avoid a PHP notice.

If the associated post or term no longer exists, mark the menu item as invalid.

Props mehulkaklotar, kamrankhorsandi, cristiano.zanca, SergeyBiryukov.
Fixes #31703.

Users: Adjust [45806] to make sure `$all_userids` is always defined.

Props kbrownkd.
Fixes #47936.

Site Health: Add timezone to Site Health Info page.

Props justinahinon, sharaz, artisticasad, Rarst.
Fixes #47842.

Taxonomy: Ensure consistency of `hide_empty` in term queries when `taxonomy` is excluded.

When querying for terms in hierarchical categories using `hide_empty=true`,
results have historically included parent terms which are themselves
unattached to any objects (are "empty") but which have non-empty descendent
terms. Because this process involves walking the descendant tree, we avoid it
when we detect that the queried taxonomies are not hierarchical. (This
behavior was introduced in [5525].)

When the `taxonomy` parameter of `get_terms()` was made optional - see #35495,
[36614] - it affected the mechanism for avoiding unneccessary tree walks,
since there may not be any explicitly declared taxonomies to run through
`is_taxonomy_hierarchical()`. As a result, term queries excluding `taxonomy`
did not check descendants, and empty parents with non-empty children were not
included in `hide_empty` results.

We correct the behavior by crawling term descendants when the `taxonomy`
argument is absent, which means that we're querying for terms in all taxonomies.

Props smerriman.
Fixes #37728.

Date/Time: Rewrite and simplify `get_gmt_from_date()`, `get_date_from_gmt()`, and `iso8601_to_datetime()` using `wp_timezone()`.

Improve unit test coverage.

Props Rarst, goodevilgenius.
Fixes #31809.

Date/Time: Simplify the date comparing logic in `WP_Community_Events::trim_events()`.

The Events API returns event date without timezone information, so trying to parse it into a timestamp and compare to a WP timestamp is pointless.

Props Rarst.
Fixes #47463.

Build Tools: Pass the LOCAL_DIR environment variable through to the phpunit Docker container.

This allows code running inside the container to know whether it's supposed to be running in `build` or `src`.

See #47767.

Date/Time: Revert unintended changes from [45882].

Props TimothyBlynJacobs.
See #25768.

Date/Time: Introduce `current_datetime()` for better time operations.

Returning a `DateTimeImmutable` representation of the current moment in time, this allows for a more flexible and reliable use than `current_time()` provides.

Props Rarst.
Fixes #47464.

Date/Time: Rewrite and simplify `date_i18n()` using `wp_timezone()` to address multiple issues with certain date formats and timezones, while preserving some extra handling for legacy use cases.

Improve unit test coverage.

Props Rarst, remcotolsma, raubvogel.
Fixes #25768.

Coding Standards: Dynamic hooks should be named using interpolation not concatenation.

Props arena, desrosj.
Fixes #47052.

Coding Standards: Add missing `break` for the default case in `wp_privacy_anonymize_data()`.

Props itowhid06.
Fixes #47921.

Date/Time: Use `wp_timezone()` in `WP_Date_Query::build_mysql_datetime()` to address timezone issues.

Improve unit test coverage.

Props Rarst, Biranit, birgire, jave.web, SergeyBiryukov.
Fixes #41782.

Build Tools: Don't use git for package installs.

While NPM supports installing packages from git locations, this requires `git` to be in the path, which won't necessarily be true, particularly on Windows.

We can download the release versions for these packages, instead.

Fixes #47916.

Users: Adjust [45708] to make sure `wp_update_user()` does not issue a `WP_Error` if a single site was previously set up as Multisite and there's still a `spam` field in the user table.

Add a unit test.

Props azaozz, SergeyBiryukov.
Fixes #45747.

Administration: Adjust [45814] to address a backward compatibility issue for plugins passing multiple CSS classes to `add_settings_error()`.

Only add the `notice-` prefix for `error`, `success`, `warning`, `info` CSS classes, keep other classes as is.

Add unit tests for `settings_errors()`.

Props afercia, SergeyBiryukov.
Fixes #44941.

Docs: Correct type for the `$deprecated` argument of `get_terms()`.

Props itowhid06.
Fixes #47915.

Docs: Fix typo in `_wp_make_subsizes()` DocBlock.

Props itowhid06.
Fixes #47913. See #40439.

Customizer: Trim whitespace from custom link URLs.

This complements a similar fix for the Menus screen in [45655].

Props donmhico, audrasjb.
Fixes #47888. See #47723.

Docs: Update `@since` tag for new JS functions and variables introduced in [45572].

Props garrett-eclipse.
See #47145.

Twenty Seventeen: Fix tabs vs. spaces in [45764].

See #47414.

Twenty Eleven: Fix tabs vs. spaces in [45763].

See #47414.

Twenty Seventeen: Adjust [45764] to conform to CSS Coding Standards.

See #47414.

Twenty Eleven: Adjust [45763] to conform to CSS Coding Standards.

See #47414.

Tests: Remove `$wpdb` global reference from `test_wp_insert_user_with_empty_data()`.

See #47902.

Users: In `wp_insert_user()`, account for the `wp_pre_insert_user_data` filter returning empty data.

Props juliobox, SergeyBiryukov.
Fixes #47902.

Date/Time: Fix race conditions in `current_time()` tests.

* Restore default timezone before performing assertions to avoid affecting other tests in case of failure.
* Use delta comparison for timestamps to avoid race conditions.

Props SergeyBiryukov, desrosj.
Fixes #45821.

Date/Time: Use PHP `DateTime` class API in `current_time()`.

Only use the legacy WP timestamp approach (a sum of timestamp and timezone offset) for `timestamp` and `U` formats without the `$gmt` flag.

Otherwise, make sure the function returns correct local time for any format.

Props Rarst, jdgrimes.
Fixes #40653.

Coding Standards: Use long array syntax in `Tests_WP_Timezone::timezone_offset_provider()`.

Per https://make.wordpress.org/core/2019/07/12/php-coding-standards-changes/, arrays must be declared using long array syntax for clarity.

See #24730.

Coding Standards: Use `KB_IN_BYTES` in `get_file_data()`.

See #22405, #47632.

Date/Time: Introduce `wp_timezone_string()` and `wp_timezone()` for unified timezone retrieval.

* `wp_timezone_string()` retrieves the timezone from current settings as a string. Uses the `timezone_string` option to get a proper timezone if available, otherwise falls back to an offset.
* `wp_timezone()` retrieves the timezone from current settings as a `DateTimeZone` object. Timezone can be based on a PHP timezone string or a `±HH:MM` offset.

Props Rarst, remcotolsma, johnjamesjacoby, rmccue.
Fixes #24730.

Coding Standards: Fix WPCS violations in [45851].

See #25347.

Date/Time: In `wp_insert_post()`, when checking the post date to set `future` or `publish` status, use string comparison to work around far future dates (year 2038+) on 32-bit systems.

Props Rarst, nofearinc.
Fixes #25347.

Date/Time: In `WP_Date_Query::__construct()`, return early if `$date_query` is empty or not an array.

Props vishalkakadiya.
Fixes #47392.

Tests: Add an xdebug group for tests that require xdebug.

These tests are now also run as their own part of the Travis build, to ensure performance of other tests isn't affected by the presence of xdebug.

Fixes #40532.

Multisite: Remove truncation to allow clearers identification of longer site names

Previously the sites were truncated which meant longer names but with ending identifications were unable to be seen as different. This shows the full site name to allow easier understanding.

Props tferry, melinedo, afercia, jeremyfelt
Fixes: 47112

Privacy: Add descriptions for sections in a personal data export file.

Props garrett-eclipse, Venutius, karmatosed.
Fixes #45491.

Plugins: Adjust margin for plugin headings on "Add Plugins" screen to avoid overlapping with "Network Activate" button.

Props justinahinon, chetan200891.
Fixes #47600.

Pings/Trackbacks: In `wp_xmlrpc_server::pingback_ping()`, strip inline JS and CSS while trying to figure out the pingback context.

Props david.binda.
Fixes #47283.

Docs: Improve documentation for `wp_set_auth_cookie()` and related functions.

Props arafat, SergeyBiryukov.
Fixes #47886.

Docs: Add a missing return type.

See #47110

Add @ticket annotations for [45812].

Props birgire.
See #43709.

Build Tools: Improve `local-env` start behaviour under Docker Toolbox.

Docker Toolbox requires port forwarding to be configured, but generates error when trying to forward a port that's already been taken.

This change removes clashing port forwarding rules before adding our own.

See #47767.

Administration: Replace legacy `updated` message type in `add_settings_error()` calls with `success`.

See #44640.

Taxonomy: In `feed_links_extra()` and `get_the_archive_title()`, make sure the queried taxonomy term exists before accessing its properties.

Props donmhico, truchot, zaantar.
Fixes #46420.

Coding Standards: In `wlwmanifest_link()`, use concatenation instead of commas for `echo`, for consistency with `rsd_link()` and the rest of core.

See #47632.

REST API: Add @ticket annotation to test from [45813].

Props birgire.
See #42209.

Administration: In `add_settings_error()`, add `warning` and `info` as possible values for message type.

Account for these new values in `settings_errors()`, resulting in `notice-warning` and `notice-info` CSS classes.

Map legacy `error` and `updated` CSS classes to `notice-error` and `notice-success`.

Props donmhico, toddhalfpenny, flixos90, desrosj, javorszky, SergeyBiryukov.
Fixes #44640, #44941.

REST API: Always return post types list in taxonomies endpoint response as an array.

Prevents a non-sequential post type array such as [ 0 => 'post', 2 => 'page' ] from being improperly converted to an object in the taxonomy endpoint's response JSON.

Props TimothyBlynJacobs, birgire, spectacula.
Fixes #42209.

REST API: Prevent deletion of post revisions.

Allowing the client to delete revisions breaks the "audit trail" functionality. This is not allowed in WordPress and shouldn't be allowed through the API.
While not recommended, a plugin may opt-in to the previous behavior by setting a custom 'delete_post' capability for the revisions post type.

Props dlh, danielbachhuber, TimothyBlynJacobs, azaozz, kadamwhite.
Fixes #43709.

REST API: Cache results of get_item_schema on controller instances for performance.

Caches the output of get_item_schema() to avoid redundant recomputation of translatable strings and other computed values. This method is called many times per item in each REST request, and the results of the method should not vary between calls.
Additional schema fields are not cached.

Props kadamwhite, joehoyle, TimothyBlynJacobs.
Fixes #47871.

REST API: Clarify arguments passed to rest route get & update callbacks.

Update doc block argument definitions to clarify that the REST API always passes an array to the `get_callback` and always passes an entity object to the `update_callback`.

Props TimothyBlynJacobs, salzano.
Fixes #44432.

REST API: Do not send response body if status is 204 or body is null.

Status code 204 should indicate no response body is sent. Previously, a "null" string was sent, which MacOS Safari would try to parse as JSON and thereby fail to complete the request.

Props TimothyBlynJacobs, andizer, matthias.thiel.
Fixes #43691.

REST API: Add test class file incorrectly omitted from [45807].

Props @TimothyBlynJacobs.
See #43392.

REST API: Support 'object' and 'array' types in register_meta() schemas.

Extends meta registration to support complex schema values, mirroring the functionality in the settings controller.
Error when trying to modify a meta key containing schema-nonconformant data.

Props @TimothyBlynJacobs, @birgire, @mnelson4, @flixos90.
Fixes #43392.

Users: When deleting users, exclude the current user from the content existence check.

The current user cannot be deleted, so the check is redundant in that context and should only be done for other users.

Props mt8.biz, SergeyBiryukov.
Fixes #47851.

Schema: Add an index to `wp_options.autoload`.

Most sites will be unaffected by this change, but those with a large number of rows in `wp_options`, only a small number of which have `autoload` set, will see a significant performance improvement.

Sites with a large number of rows in `wp_options`, with many of them having `autoload` set will unfortunately see a performance penalty on top of the already very slow queries they're running, but this should be the minority of cases.

Props DanBUK.
Fixes #24044.

Networks and Sites: Trim site domain when creating a new site on Add New Site screen before further validation.

Props dharmin16, jeremyfelt, aubreypwd.
Fixes #44808.

Docs: Add missing `@since` tag for `WP_Site_Health::has_late_cron()`.

See #47223.

Site Health Check: New tests file missed in [45801].

Site Health Check: Increase time allowance for cron checks.

Introduces `WP_Site_Health::has_late_cron()` for late wp-cron jobs and extends the time allowance before a job is considered missed.

In a standard configuration using loopback requests, a job is considered late once past due and missed over five minutes past due.

Late and missed time frames are extended if `DISABLE_WP_CRON` is defined as `true` to allow for crontab tasks running less frequently. A job is considered late once it's 15 minutes past due and missed over one hour past due.

A file for site health unit tests has been introduced with tests for cron in critical, late and missed states.

Props rockfire, afragen, peterwilsoncc.
Fixes #47223.

Build Tools: Change the PHPUnit Docker image's working directory to match the other images.

Also, pass the `WP_MULTISITE` environment variable along to the container.

See #47767.

Build Tools: Run `composer` commands in a Docker container on Travis.

This tidies up the `.travis.yml` file a little more.

See #47767.

Widgets: Allow for short-circuiting widget output in `the_widget()` using the `widget_display_callback` filter, for consistency with output via a registered sidebar.

Props MarcGuay, donmhico.
Fixes #34226.

Docs: Correct type for `query_var` argument of `register_taxonomy()`.

Props juiiee8487, audrasjb.
Fixes #47877.

Posts, Post Types: In `wp_trim_words()` make sure the `$num_words` parameter is always an integer, as documented, to avoid a PHP warning.

Props donmhico, pikamander2.
Fixes #47867.

Users: Make `wp_list_authors()` unit tests more readable.

See #23498.

Networks and Sites: Improve documentation and variable naming in `switch_to_blog()` and `restore_current_blog()`.

In `switch_to_blog()`:

* Rename `$blog_id` to `$prev_blog_id` for clarity.
* Rename `$new_blog` to `$new_blog_id` for consistency.
* Pass `$prev_blog_id` as a second parameter to `switch_blog` action, instead of the duplicated `$new_blog_id`. This only clarifies documentation and does not affect functionality, since the values are equal in the context where the DocBlock is located.

In `restore_current_blog()`:

* Rename `$blog` to `$new_blog_id` for clarity.
* Rename `$blog_id` to `$prev_blog_id` for clarity.

Props ChriCo, jeremyfelt, SergeyBiryukov.
Fixes #45594.

Plugins: Adjust the pause before running plugin search AJAX request on "Add Plugins" screen to allow more time for using browser's autocomplete.

Props donmhico, apermo.
Fixes #46021.

Coding Standards: Fix JSHint error in [45790].

See #41545.

Site Health: Simplify the language in Status Health Info page introduction, add a link to Status page.

Props birgire, mukesh27, subrataemfluence, leogermani.
Fixes #46946.

Comments: enable typing cmd/ctrl-enter to submit comment forms.

Add a key handler on the comment form that detects the cmd/ctrl-enter key press and submits the comment form. 

Props xyfi, Lindstromer, helen, splitti.
Fixes #41545.

Remove trailing white space in upgrade.php.

See #46349.

Admin email verification:

- Add the `admin_email_lifespan` option when installing. Fixes a bug where the verification screen is shown right after installation.
- Reset the same option when upgrading and the user doing the DB upgrade is not an admin. This will ensure the email verification is shown next time an admin logs in.
- Use `site_url()` instead of `network_site_url()` for the form action. The latter seems needed only for password reset.

See #46349.

Comments: Include post permalink in comment reply link.

Include the post's permalink when generating reply links in `get_comment_reply_link()` to account for comments displayed on index and archive pages.

This reapplies [32786] which was inadvertently reverted in [42360].

Props justinahinon, donmhico.
See #33383.
Fixes #47174.

Docs: Clarify custom-fields support requirement for viewing custom post meta in REST API.

Fixes #47866.

Build Tools: Remove the old `docker-compose.yml` file, now no longer used.

See #47767.

Build Tools: Add the `docker-compose.yml` file, missed in [45783].

See #47767.

Build Tools: Miscellaneous `local-env` improvements.

- Move the functionality for controlling `local-env` out of `package.json`, into JS scripts.
- Merge the `docker-compose` config files, and move it to the root directory. This allows `docker-compose.override.yml` to work for local overrides.
- Fix nginx redirecting to port 80 under some circumstances.
- `npm run env:install` now creates `wp-tests.config.php` for you.
- Cleaned up a bunch of cruft in `.travis.yml`.

See #47767.

Site Health: Add database charset and collation information to debug info.

Props sharaz, Clorith, SergeyBiryukov.
Fixes #47828.

Docs: Improve documentation for various feed link functions and filters.

Props atachibana, SergeyBiryukov.
Fixes #47862.

Docs: Improve documentation for `get_last_updated()`.

Props atachibana.
Fixes #47861.

Docs: Improve documentation for `get_page_by_title()`.

Props atachibana.
Fixes #47860.

Docs: Document the `show_split_view` argument for `wp_text_diff()`.

Convert `$args` array documentation to hash notation.

Props riddhiehta02, jeremyfelt, SergeyBiryukov.
Fixes #47224.

Widgets: Replace http with https in the link placeholder widget image

The existing placeholder can make the user think that they must use http. We should encourage the use of https. 
Also, the block editor uses https for its placeholders. Let's add some consistency.

Props Chaton666, audrasjb, mukesh27.
Fixes #46320.

Twenty Sixteen: Correct HelpHub URL in `readme.txt`.

See #47771.

Twenty Nineteen: Add missing `Installation` section to `readme.txt`, for consistency with other themes.

See #47857.

Twenty Nineteen: Add missing copyright information.

Props poena, kjellr.
Fixes #47857.

Twenty Nineteen: Correct license URI.

Props munyagu, shital-patel.
Fixes #47850.

Feeds: Introduce the `get_self_link()` function.

Corresponds to the `self_link()` template function.

This matches other feed template functions, using one function to get the value, and a different function to echo it.

Props jojotjebaby, mobeen-abdullah, donmhico, audrasjb, dshanske.
Fixes #44838.

REST API: In `get_rest_url()`, check if `$_SERVER['SERVER_NAME']` is set to avoid a PHP warning in CLI context.

Props paulschreiber.
Fixes #47854.

Bootstrap/Load: Change "Insufficient Requirements" `wp_die()` heading to "Requirements Not Met", which is more appropriate for the context it's used in.

Props yoavf.
Fixes #47575.

Emoji: Upgrade Twemoji to 12.1.2.

This upgrade adds support for the transgender flag: 🏳️‍⚧️

There's some additional housekeeping in this commit:

- Twemoji recently rearranged their repository and package, so `Gruntfile.js` needed tweaking to allow for that.
- As only new files were added in this Twemoji release, the CDN version didn't need updating.

Fixes #47852.

Bundled Themes: Audit and update version numbers passed to `wp_enqueue_script()` to ensure proper cache busting.

Props dswebsme, ianbelanger, justinahinon.
Fixes #46981.

Bundled Themes: Audit and update version numbers passed to `wp_enqueue_style()` to ensure proper cache busting.

Props dswebsme, ianbelanger, desrosj.
Fixes #46979.

Administration: Show a warning in Reading Settings when a Privacy Policy page is accidentally set as a Homepage or Posts page.

Props garrett-eclipse, subrataemfluence.
Fixes #46831.

Bump grunt-patch-wordpress to 2.0.0

Fixes #47845
Props pento, kadamwhite, netweb, jorbin

Twenty Seventeen: Correct height for a Button block without text.

Props ianbelanger, laurelfulford, nayana123.
Fixes #47414.

Twenty Eleven: Correct height for a Button block without text.

Props ianbelanger, laurelfulford, nayana123.
See #47414.

Build Tools: Switch all Travis PHPUnit jobs over to Docker-based PHP.

Additionally, there are a handful of related minor changes in this commit:
- `.travis.yml` has been tidied up a little.
- [45745] was incorrectly marking Travis jobs as passed when some PHPUnit runs failed.
- Add the `LOCAL_PHP_MEMCACHED` environment variable, for enabling Memcached.
- Add the `env:pull` NPM script, for refreshing Docker images.

See #47767.

Twenty Nineteen: Revise Latest Posts block styles to support post content options.

Props kjellr, ianbelanger.
Fixes #47340.

Twenty Nineteen: Remove duplicate `height` and `width` attributes from SVG icons.

The attributes are added via `TwentyNineteen_SVG_Icons::get_svg()`, there's no need to have them separately in SVG sources.

Props mukesh27, albertomake.
Fixes #47128.

Coding Standards: Use strict comparison in `wp-admin/edit.php`.

Props davidbaumwald.
Fixes #47201.

Remove trailing white space in upgrade.php after [45757].

See #46349.

Add admin email verification screen. Shown every six months after an admin has logged in.

Also includes WPCS fixes for wp-login.php.

Props andraganescu, boemedia, lessbloat, azaozz.
See #46349.

Administration: Correct "Quick Edit" link height in list tables for consistency with other action links.

Props jobthomas, burhandodhy.
Fixes #47815.

Coding Standards: Fix WPCS violation in [45754].

See #46570.

General: Correctly detect large floats in `is_serialized()`.

Props killerbishop, donmhico, hoythan.
Fixes #46570.

Feeds: Escape `&` characters in `atom_site_icon()` for XML, for consistency with `rss2_site_icon()`.

Props abhijitrakas, shawfactor.
Fixes #47482.

Coding Standards: Use strict comparison in `wp-admin/options-reading.php`.

Props subrataemfluence.
Fixes #46834.

Plugins: Use `include_once` for `wp-admin/includes/plugin-install.php` in `WP_Plugin_Install_List_Table::prepare_items()`.

This brings consistency with the other instances where the file is included, and allows for reusing its functions in custom code.

Props engelen, desrosj.
Fixes #38874.

Site Health: Use correct variable when checking PHP requirements for a plugin update in `WP_Plugins_List_Table::single_row()`.

Props diddledan, sharaz, vaishalipanchal.
Fixes #47835.

Docs: Correct `@type` annotation for `WP_Http_Curl` properties.

Props diddledan.
Fixes #46860.

Docs: Correct `@type` annotation for `WP_HTTP_Cookie::$expires`.

Props diddledan.
Fixes #46859.

Upgrade/Install: Make sure `translate_level_to_role()` always returns a value.

Props diddledan.
Fixes #46848.

Posts, Post Types: Update, not delete the `page_for_posts` option in `_reset_front_page_settings_for_post()` when a linked page is deleted or trashed.

Props diddledan.
Fixes #46850.

Build Tools: Add a WordPress Development Environment.

This commit adds the first iteration of a Docker-based config for setting up a local WordPress development environment.

Props pento, noisysocks, mcsf, pbearne, isabel_brison.
See #47767.

Posts, Post Types: Revert unintended change from [45742].

See #46503.

Administration: Display a warning at the top of "All Settings" screen.

Props zodiac1978, donmhico, pixolin.
Fixes #47718.

Docs: Add missing description for `$post` global.

Props immeet94.
Fixes #46503. See #47110.

Docs: Remove incorrect `@return` tags in `comment_reply_link()` and `post_reply_link()` DocBlocks.

Props atachibana.
Fixes #47826.

Docs: Add missing description for `$current_screen` global.

Props mukesh27.
Fixes #45604. See #47110.

Docs: Add missing description for `$wp_query` and `$wp_the_query` globals.

Props mukesh27.
See #45604, #47110.

Docs: Add missing description for `$wp_locale_switcher` global.

See #45604, #47110.

Docs: Add missing description for `$wp_locale` global.

Props mukesh27.
See #45604, #47110.

Docs: Add missing description for `$wp` global.

See #45604, #47110.

Docs: Add missing description for `$wp_rewrite` global.

See #45604, #47110.

Docs: Add missing description for `$wpdb`, `$wp_db_version`, and `$wp_current_db_version` globals.

Props mukesh27, utsav72640, immeet94, SergeyBiryukov.
See #45604.

Docs: Fix typo in a comment in `WP_Site_Health::get_test_theme_version()`.

See #47110.

Site Health: If `WP_DEFAULT_THEME` doesn't exist, use `WP_Theme::get_core_default_theme()` as a fallback.

Props ajayghaghretiya1, juliobox, SergeyBiryukov.
Fixes #47299.

Script Loader: Send a 400 Bad Request status code in `load-scripts.php` and `load-styles.php` if the required `load[]` parameter is not set.

Props compilenix.
Fixes #44108.

PHP 7.4 compatibility fix / accessing arrays/string using curly brace syntax

PHP used to allow both square brackets and curly braces to be used interchangeably for accessing array elements and string offsets. The curly bracket syntax is only allowed in a limited set of cases and can be confusing for people not used to it.
PHP 7.4 will deprecate the curly brace syntax for accessing array elements and string offsets and it is expected that support will be completely removed in PHP 8.0.
Ref: https://wiki.php.net/rfc/deprecate_curly_braces_array_access

See #47751.
Props jrf.

Accessibility: Improve the differences between revisions.

Color alone is not sufficient to visually communicate differences.

- adds `plus` and `minus` icons to the changed lines
- adds visually hidden text: `Added`, `Deleted`, and `Unchanged` to clarify the differences to assistive technologies users

Props birgire, audrasjb, kjellr, adamsilverstein.
Fixes #43532.

Accessibility: Remove title attributes from the Meta widget.

- removes the `Powered by WordPress, state-of-the-art semantic personal publishing platform.` title attribute
- removes the title attribute from the abbreviations: contrary to a common belief, title attributes on abbreviations are only available to a minority of users, see https://developer.paciellogroup.com/blog/2019/03/short-note-the-abbreviation-appreciation-society/
- changes the term `RSS` to `feed`, as `RSS` is a technical term not all users are supposed to be familiar with
- improves the `widget_meta_poweredby` filter documentation

Props nishitlangaliya, chetan200891, audrasjb.
See #46980, #24766.
Fixes #46978.

Menus: Fix the Custom Links text fallback.

When adding a Custom Link and leaving the "Link Text" field empty, WordPress used to set a default fallback text: "Menu Item".

The changes in [36379] broke this behavior making the fallback text: ` (Pending)`, with a leading space.

Pending major refactoring of the Menus page (which is going to use a block-based user interface) this change just restores the original behavior by adding the fallback text to the related AJAX response.

Props christophherr, Fencer04, thakkarhardik, backermann1978, audrasjb.
Fixes #38415.

Accessibility: Improve the way emojis are announced by screen readers.

Adds an ARIA `role="img"` to the emojis markup in the front end. While the ARIA role is technically redundant, it helps Safari and VoiceOver to properly announce the emojis as "image". Without the role, they announce a generic "group" role.
Tested with Safari 12.1.1 / VoiceOver 9.

Props pento.
See #37486.

Accessibility: Fix the `alt` attribute of the Gallery images within the Classic Editor.

Passes the images `alt` attribute value to the Gallery template used within the Classic Editor.

Props yarnboy, wpboss.
Fixes #47687.

Posts, Post Types: Check the result of `wp_update_post()` in `wp_trash_post()` and `wp_untrash_post()`.

Props abhijitrakas, manzoorwani.jk, siliconforks.
Fixes #47773.

Taxonomy: Fix deprecated calls to `get_terms()`.

The taxonomy should be passed as part of `$args`, rather than as its own argument.

Props sgastard, mukesh27, SergeyBiryukov.
Fixes #47819.

Customize: Make the color picker close when clicking on the empty area on the right.

Props monikarao.
Fixes #47693.

Twenty Thirteen: Make `twentythirteen_author_bio_template()` use author templates if exist, fall back to regular template hierarchy otherwise.

See #32096.

Twenty Fifteen: Make `twentyfifteen_author_bio_template()` use author templates if exist, fall back to regular template hierarchy otherwise.

See #32096.

Twenty Thirteen: Prevent `author-bio.php` partial template from interfering with rendering an author archive of a user with the `bio` username.

Props rclations, ianbelanger, lordlod, SergeyBiryukov.
Fixes #32096.

Twenty Fifteen: Prevent `author-bio.php` partial template from interfering with rendering an author archive of a user with the `bio` username.

Props rclations, ianbelanger, lordlod, SergeyBiryukov.
See #32096.

Users: Clean user cache in `check_password_reset_key()` tests.

Props davidbaumwald, spacedmonkey.
See #45845.

Users: Replace raw SQL query in `check_password_reset_key()` with `get_user_by()`.

Props davidbaumwald, iworks, spacedmonkey.
Fixes #45845.

Users: Use `clean_user_cache()` in `wp_insert_user()`, `wp_update_user()`, `wp_set_password()`, `add_user_to_blog()`.

Props spacedmonkey.
Fixes #47021.

Users: Use `wp_update_user()` in `get_password_reset_key()`.

Props jayswadas, spacedmonkey, donmhico, SergeyBiryukov.
Fixes #45746.

Users: Reorganize `user_nicename`, `user_url`, `user_registered` setting in `wp_insert_user()` for consistency with the order or fields in the database.

See #45746.

Users: Use `get_password_reset_key()` in `wp_new_user_notification()`.

Props mrasharirfan, spacedmonkey.
Fixes #45745.

Taxonomy: Correct some strict comparisons after [45710].

See #47573.

Coding Standards: Use strict comparison in `wp-includes/taxonomy.php`.

Props andizer, SergeyBiryukov.
Fixes #47573.

Coding Standards: Fix WPCS violations after [45708].

See #45747.

Users: Deprecate `update_user_status()` in favor of `wp_update_user()`.

Props spacedmonkey, SergeyBiryukov.
Fixes #45747.

Database: Use a strict comparison for `has_filter()` check in `wpdb::placeholder_escape()`.

The filter is added with a priority of `0`, so a loose comparison had an unintended effect of adding the filter on every call.

Props withinboredom.
Fixes #47430.

REST API: Skip processing fields which are not present in the selected context.

In `WP_REST_Controller::get_fields_for_response()`, exclude fields which are not registered to appear in the request's context.

In conjunction with r45705 this prevents the unnecessary computation of the sample permalink when making a request that is not context=edit.

Props dlh.
Fixes #45605.

REST API: Generate sample permalink only when a dependent field is requested.

The sample permalink will now only be generated if the derivative `permalink_template` or `generated_slug` fields are to be included in the response, preventing an unnecessary database request for each post (via `wp_unique_post_slug()`) when those fields are not requested.

Props dlh.
See #45605.

Docs: Correct parameter documentation for `bulk_edit_custom_box` and `quick_edit_custom_box` actions.

Props abrain.
Fixes #47810.

Docs: Correct parameter type and description for `is_email` filter.

Props jenkoian.
Fixes #47793.

Docs: Correct `@return` value description for `get_term_link()`.

Props garrett-eclipse.
Fixes #47806.

Media: Reduces the bulk media options to have one primary button

This fixes where 2 primary buttons were showing for bulk actions within media trash.

Props garrett-eclipse, afercia, ianbelanger, SergeyBiryukov
Fixes #46757, #46758

Admin: Improve Dashboard icon contrast.

The icons used across the dashboard had too low contrast to pass AA WCAG guidelines. They’re now slightly darker for better contrast.

Props @melchoyce, @SergeyBiryukov, @chetan200891 , @kjellr 
Fixes #46935

Rewrite Rules: Check if `$wp_rewrite->flush_rules()` is callable before calling it in `flush_rewrite_rules()`.

Props bsetiawan88, markjaquith.
Fixes #47087.

Users: Use case-insensitive email address comparison when checking whether "Grant this user super admin privileges" checkbox should be displayed on Edit User screen.

Props trepmal.
Fixes #47119.

Coding Standards: Fix WPCS violations in `wp-admin/includes/class-walker-nav-menu-edit.php`.

Props sudhiryadav, audrasjb.
Fixes #46902.

Coding Standards: Fix WPCS violations in [45694].

See #47466.

Docs: Improve the DocBlocks for `got_mod_rewrite()`, `extract_from_markers()`, `insert_with_markers()`.

See #47110.

Rewrite Rules: Add a comment to `# BEGIN/END` `.htaccess` markers to clarify that the directives are dynamically generated, and should only be modified via WordPress filters.

Introduce `insert_with_markers_inline_instructions` filter to modify the default instructions text.

Props bradleyt, SergeyBiryukov.
Fixes #47466.

Permalinks: Improve appearance of URL examples on Permalink Settings screen.

Props luan-ramos, sarath.ar.
Fixes #41559.

Administration: Allow breaking long strings in `<code>` tags at any point, to avoid overflowing on mobile.

Props david.binda, mukesh27.
Fixes #47329.

Site Health: Consistently use `wpdb::db_version()` for checking the database server version, instead of partically replicating its functionality.

Props Clorith, wpfed.
Fixes #47738.

I18N: Display the logged out message in the user's locale

I18N: Following [45688], remove test for removed method.

See #44865.

I18N: Use RTL stylesheets when running from /src.

To run WordPress from /src you have to use the `--dev` flag which also builds the RTL stylesheets thus the admin notice and force to LTR is no longer required.

See #44492.
Fixes #44865.

REST API: Pass current request object to `rest_authentication_errors` filter in `WP_REST_Server::check_authentication()`.

Fixes #46907.

Tools: Remove internationalization tools (also known as `makepot.php`).

It has been a great pleasure to work with `makepot.php` over the past [https://i18n.trac.wordpress.org/changeset/4169/ 11 years] but now it's time to say goodbye.
The tools have been integrated into WP-CLI as [https://developer.wordpress.org/cli/commands/i18n/make-pot/ wp i18n make-pot] and [https://developer.wordpress.org/cli/commands/i18n/make-json/ wp i18n make-json]. The new commands were optimized to support current PHP versions and are more flexible and reliable when extracting strings for PHP, and JavaScript.

Access to the old tools continue to exist in previous branches or at https://i18n.svn.wordpress.org/tools/.

Fixes #45287.

I18N: Add support for custom `WP_PLUGIN_URL` in `load_script_textdomain()`.

Plugins may not be on the same host/path as the rest of the content. To support loading translations for this setup check if the script source matches `plugins_url()`.
Also fixes an undefined index notice when a custom content URL has no path.

Props odminstudios, ocean90.
Fixes #46336, #46387.

Accessibility: Toolbar: Make the `min-width` value for `#wpadminbar` at `782px` breakpoint consistent with that of `<body>`.

This ensures that the "My Account" toolbar item stays visible at high zoom levels.

Props isabel_brison, chetan200891.
Fixes #47603.

Accessibility: Taxonomy: When a new category or tag is being added, show a spinner and noop the button to avoid multiple requests.

Props andg, afercia, guddu1315, SergeyBiryukov.
Fixes #47607.

Administration: Merge CSS rules for `#adminmenu .wp-submenu a` in one place.

Props ozmatflc, AkSDvP.
Fixes #47780.

REST API: Make "Could not update meta value in database" error messages more helpful.

Props apermo, AkSDvP.
Fixes #46252.

Site Health: Show parent theme in its own accordion on Site Health Info screen; rename "Other Themes" to "Inactive Themes".

Props garrett-eclipse, mukesh27, Clorith, xkon, msaggiorato.
Fixes #46925.

Coding Standards: Fix newlines in `wp-includes/date.php`.

See #47775.

Coding Standards: Move `wp-includes/date.php` to `wp-includes/class-wp-date-query.php`.

This renames the file containing the `WP_Date_Query` class to conform to the coding standards.

This commit also includes:

- A new `date.php` that includes the new file, for anyone that may've been including the file directly.
- Replaces references to the old filename with the new filename.

Fixes #47775. See #47632.

I18N: Update translator comment missed in [45676].

See #47771.

I18N: Update translator comments after [45674].

See #47771.

Bundled Themes: Replace Codex URLs with a corresponding HelpHub or DevHub article.

Props ianbelanger, tobifjellner, SergeyBiryukov.
See #47771.

General: First pass at replacing Codex URLs with a corresponding HelpHub or DevHub article.

Props ianbelanger, tobifjellner, SergeyBiryukov.
See #47771.

Upgrade/Install: Bring some consistency to installation screen styles.

* Include `forms.css` and `l10n.css`, for consistency with login screen and other admin screens.
* Remove redundant `@import` directives from `login.css` for files already declared as dependencies.
* Adjust margin on password strength meter for consistency with other fields.
* Increase font size for "You will need this password to log in" notice.
* Fix misaligned icon on "Hide" button for the password.

Props iseulde, [email protected], bassgang, cdog, johnbillion, nmenescardi, mukesh27, SergeyBiryukov.
Fixes #35776, #47757, #47758.

Docs: Clarify that `is_network_admin()` does not check if the site is a Multisite network; `is_multisite()` should be used for that.

Props svovaf, dilipbheda, tazotodua.
Fixes #47415.

Posts, Post Types: Introduce `is_sticky` filter in `is_sticky()` to provide more flexibility for custom sticky post implementations.

Props dehisok, greenshady.
Fixes #37629.

Code Editor: Check for correct `mode` value in `wp.codeEditor.initialize` to enable autocomplete support for PHP.

Props ediamin.
Fixes #47769.

Permalinks: Update URLs for "Changing File Permissions" documentation article.

Props patilswapnilv, ianbelanger, SergeyBiryukov.
Fixes #47768.

Coding Standards: Use correct variable in `wp_dropdown_categories()` after [45667].

See #45059.

Coding Standards: Rename `$r` variable used with `wp_parse_args()` to `$parsed_args` for clarity.

Props freewebmentor.
Fixes #45059.

Coding Standards: Move the remaining PHPCS errors to report as warnings, and add Travis tests.

The remaining error-level coding standards issues (specifically, associated with the sniffs `WordPress.PHP.YodaConditions.NotYoda`, `WordPress.NamingConventions.ValidVariableName.VariableNotSnakeCase`, `WordPress.DB.PreparedSQL.InterpolatedNotPrepared`, `WordPress.DB.PreparedSQL.NotPrepared`, and `WordPress.Files.FileName.InvalidClassFileName`) are marked as warnings, until they're all addressed.

This change allows us to run linting on Travis across the entire codebase, ensuring no other error-level violations can be introduced.

Additionally, PHPCS will now cache results locally, drastically improving performance for subsequent checks: scanning the entire codebase takes 1-2 minutes the first time, and less than one second for subsequent checks.

See #47632.

Coding Standards: Fix a filename replacement missed in [45663].

See #47632.

Coding Standards: Move `wp-includes/class-oembed.php` to `wp-includes/class-wp-oembed.php`.

This renames the file containing the `WP_oEmbed` class to conform to the coding standards.

This commit also includes:

- A new `class-oembed.php` that includes the new file, for anyone that may've been including the file directly.
- Replaces references to the old filename with the new filename.

See #47632.

Coding Standards: Move wp-admin/custom-background.php to wp-admin/includes/class-custom-background.php

This renames the file containing the Custom_Background class to conform to the coding standards.

This commit also includes:

- A new custom-background.php that includes the new file, for anyone that may've been including the file directly.
- Replaces a reference to the old filename with the new filename.

See #47632.

Coding Standards: Exclude a handful of incorrectly named files that won't be renamed.

See #47632.

Coding Standards: Improve spacing of `printf()` calls in the admin About pages.

Props garrett-eclipse.
Fixes #47734.

I18N: Make URLs to `https://wordpress.org/about/` and related pages translatable, as they can now be localized on Rosetta sites.

Props mukesh27.
Fixes #46386.

Customizer: Show all widgets when the search field is cleared.

When clicking the clear button on the widget search field, the search results should refresh to show all widgets.

Props Mahesh901122.
Fixes #47534.

Editor: Replace external Classic Editor plugin URL with a link to Add Plugins screen with Classic Editor pre-selected.

This applies to messages displayed when JavaScript is disabled in Block Editor, or an incompatible meta box is used.

Props garrett-eclipse, derweili, afercia.
Fixes #47487.

Coding Standards: Fix WPCS issues in [45655].

See #47723.

Menus: Trim whitespace from custom link URLs.

Props majemedia, SergeyBiryukov.
Fixes #47723.

Coding Standards: Move `wp-admin/custom-header.php` to `wp-admin/includes/class-custom-image-header.php`

This renames the file containing the `Custom_Image_Header` class to conform to the coding standards.

This commit also includes:
- A new `custom-header.php` that includes the new file, for anyone that may've been including the file directly.
- Replaces references to the old filename with the new filename.

See #47632.

Coding Standards: Exclude some class names from checks when they can't be renamed.

Renaming the classes would likely cause back compat issues, so the safest option is to allow this handful to continue unchanged.

See #47632.

Coding Standards: Fix WPCS issues in [45651].

See #38195.

Media: Add "Documents", "Spreadsheets", and "Archives" groups to file type filter in Media Library.

Props zodiac1978, swissspidy, karmatosed, SergeyBiryukov.
Fixes #38195.

Administration: In `admin-ajax.php`, send `X-Robots-Tag` header earlier, so that it applies before `wp_die()` when no action parameter was provided.

Props robi-bobi, harryfear, garrett-eclipse.
Fixes #47711.

Site Health: Use consistent verbiage for "Learn more" links.

Props ronakganatra, garrett-eclipse.
Fixes #47302.

Site Health: Replace "harddrive" with "device" on Site Health Info screen.

Props chetan200891, timhavinga, Cybr, Clorith.
Fixes #46965.

I18N: Merge duplicate "Your plugins/themes/translations are all up to date" strings.

Props ramiy.
Fixes #47252.

Media: Add a unit test for `wp_get_mime_types()`.

Props pbearne.
Fixes #47701.

Media: Sort the new sizes array by priority when creating image sub-sizes.

See #40439.

Customize: In `WP_Customize_Widgets::capture_filter_pre_update_option()`, return the filtered value instead of `null` when bailing early for ignored options.

Props dlh.
Fixes #47715.

Docs: Move the `do_mu_upgrade` DocBlock out of the preceding `if` statement.

Props ChriCo, dkarfa.
Fixes #47710.

Docs: Correct `@since` tag for `do_mu_upgrade` hook, for consistency with `after_mu_upgrade` and `wpmu_upgrade_site`.

See #47110.

Comments: Fix typo in comment reply observer options.

Props maguiar.
Fixes #47706. See #46260.

Code Modernisation: Revert [45624].

Changing the method signatures on `Walker` causes back compat issues.

See #47678.

Code Modernisation: Fix known instances of array access on data types that can't be accessed as arrays.

PHP 7.4 addes a warning when trying access a null/bool/int/float/resource (everything but array, string and object) as if it were an array.

This change fixes all of these warnings visible in unit tests.

Props jrf.
See #47704.

Code Modernisation: Document when the Hash polyfills can be removed.

The Hash extension cannot be disabled as of PHP 7.4. So, while we can't remove these polyfills yet, we can document when we'll be able to.

Props jrf.
Fixes #47698.

Code Modernisation: Remove the SPL autoloader polyfill.

As of PHP 5.3, the SPL extension cannot be disabled, so we no longer need this polyfill.

The file is kept with a `_deprecated_file()` call, to alert any plugins or themes that may be loading it directly.

Props jrf, ayeshrajans.
See #47698, #46630.

Code Modernisation: Remove the `array_replace_recursive()` polyfill.

This function was added in PHP 5.3.0, so we no longer need the polyfill.

Props jrf.
See #47698.

WPDB: Allow custom data to be added to logged queries.

This adds a new method, `wpdb::log_query()`, and a new filter, `log_query_custom_data`. The custom data is stored as a new element in each entry of the `wpdb::$queries` array.

Props CrazyJaco, johnbillion, pento.
Fixes 42151.

I18N: Add context for theme filter strings in `WP_MS_Themes_List_Table::get_views()`.

Props audrasjb.
Fixes #47695.

Upgrade/Install: Remove debugging artifacts from `wp-admin/upgrade.php` added in [1229].

Props rahulvaza.
Fixes #47074.

REST API: Allow `rest_get_avatar_urls()` to accept full user, post, or comment objects, rather than just an email address, to provide better flexibility for alternative avatar data.

Since the function uses `get_avatar_url()` internally, which already supports it, this should not have any backward compatibility concerns.

Props donmhico, dshanske, pputzer, joehoyle, TimothyBlynJacobs.
Fixes #40030.

TinyMCE: fix adding of too many undo levels for wpviews. The HTML changes several times when a wpview is added. We only want one undo level. Also fixes cases when the cursor is next to an embeddable URL in the Text tab and the user switches to the Visual tab.

See #45307.

Code Modernisation: Introduce the spread operator in `wpdb::prepare()`.

Rather than relying `func_get_args()` to retrieve arbitrary function arguments, we can now use the spread operator to assign them directly to a variable.

Props jrf.
See #47678.

Code Modernisation: Introduce the spread operator in `widgets.php`.

Rather than relying `func_get_args()` to retrieve arbitrary function arguments, we can now use the spread operator to assign them directly to a variable.

Props jrf.
See #47678.

Code Modernisation: Introduce the spread operator in `theme.php`.

Rather than relying `func_get_args()` to retrieve arbitrary function arguments, we can now use the spread operator to assign them directly to a variable.

Props jrf, pento.
See #47678.

Code Modernisation: Introduce the spread operator in `walk_page_dropdown_tree()`.

Rather than relying `func_get_args()` to retrieve arbitrary function arguments, we can now use the spread operator to assign them directly to a variable.

Props jrf.
See #47678.

Customize: Fix text direction for color picker in RTL.

Props vjik for the report.
Fixes #47688. See #23740.

Code Modernisation: Introduce the spread operator in `add_post_type_support()`.

Rather than relying `func_get_args()` to retrieve arbitrary function arguments, we can now use the spread operator to assign them directly to a variable.

Props jrf, pento.
See #47678.

Code Modernisation: Introduce the spread operator in `Walker`.

Rather than relying `func_get_args()` to retrieve arbitrary function arguments, we can now use the spread operator to assign them directly to a variable.

Props jrf.
See #47678.

Code Modernisation: Introduce the spread operator in `WP_User`.

Rather than relying `func_get_args()` to retrieve arbitrary function arguments, we can now use the spread operator to assign them directly to a variable.

Props jrf.
See #47678.

Code Modernisation: Introduce the spread operator in `capabilities.php`.

Rather than relying `func_get_args()` to retrieve arbitrary function arguments, we can now use the spread operator to assign them directly to a variable.

Props jrf.
See #47678.

Editor: Make registered editor stylesheets (editor-style.css) available to the front-end.

Props webmandesign, azaozz.
Fixes #34882.

TinyMCE: fix flickering inline toolbar when showing a tooltip. Take two.

Fixes #44911.

Block Editor: Avoid a PHP warning when a theme adds an editor style with an empty filename.

Fixes #45739.

Block Editor: Fix the link to the classic editor when incompatible meta boxen are detected.

Props tmatsuur, mukesh27.
Fixes #45935.

Coding Standards: Remove extra whitespace in list tables' `column_cb()` methods.

See #47632.

Coding Standards: Remove extra whitespace in `wp-admin/includes/image-edit.php`.

See #47632.

I18N: Move code out of translatable string in a `_deprecated_argument()` message in `wp_stream_image()`, `wp_save_image_file()`, and `image_edit_apply_changes()`.

Props ramiy.
Fixes #47406.

Menus: Remove extra whitespace from URLs in `Walker_Nav_Menu_Edit::start_el()`.

Props alexeyskr, SergeyBiryukov.
Fixes #47666.

Filesystem API: Check correct variable in `WP_Filesystem_Direct::dirlist()` after [45611].

Props zinigor.
Fixes #47668. See #47632.

Coding Standards: Fix instances of `WordPress.NamingConventions.ValidVariableName.UsedPropertyNotSnakeCase`.

See #46732.

Coding Standards: Fix instances of `WordPress.PHP.NoSilencedErrors.Discouraged`.

Noteable changes:
- The `magic_quotes_runtime` and `magic_quotes_sybase` settings were removed in PHP 5.4, so no longer need to be set.
- Some functions that use external libraries can generate errors that can't be tested for, so are globally allowed to silence errors.
- Quite a few functions would cause errors if `safe_mode` was set. This setting was removed in PHP 5.4.
- Only a handful of `header()` calls needed corresponding `headers_sent()` checks for unit tests to pass, but more may need to be added as the nightlies builds are tested.

See #46732.

TinyMCE: fix flickering inline toolbar when hovering over the buttons there and the vertical scrollbar is not shown (the page height is less than the window height). Improves/removes the previous fix for similar flickering but only in RTL, see #42018.

Props joakimsilfverberg, mukesh27, kokers, Howdy_McGee, noisysocks, azaozz.
Fixes #44911.

Coding Standards: Add missing translator comments to the default themes.

All default themes now have translator comments for all strings with placeholders!

See #46732.

Theme Editor: Hide the recommendation to create a child theme when editing a child theme.

Props mukesh27, davidbaumwald.
Fixes #44889.

Coding Standards: Fix the remaining issues in `/tests`.

All PHP files in `/tests` now conform to the PHP coding standards, or have exceptions appropriately marked.

Travis now also runs `phpcs` on the `/tests` directory, any future changes to these files must conform entirely to the WordPress PHP coding standards. 🎉

See #47632.

Twenty Thirteen: Add styles for the new Group block.

Add styles for the new Group block to the theme, to make sure nested blocks display correctly when using the wide and full alignments. 

Props @kjellr.
Fixes #46778.

Twenty Nineteen: Add styles for the new Group block.

Add styles for the new Group block to the theme, to make sure nested blocks display correctly when using the wide and full alignments. 

Props @kjellr, @dianeco.
Fixes #46750.

Coding Standards: Add missing translator comments.

Twentys Eleven, Sixteen, and Seventeen now have translator comments for all their strings.

Also, WPCS now doesn't show missing translator comment warnings for test files.

See #47632.

Coding Standards: Fix all `WordPress.DB.PreparedSQLPlaceholders` issues.

See #47632.

Coding Standards: Fix all `WordPress.WhiteSpace.PrecisionAlignment` issues.

See #47632.

Coding Standards: Fix all `WordPress.CodeAnalysis.AssignmentInCondition` issues.

`WordPress.CodeAnalysis.AssignmentInCondition.FoundInWhileCondition` can be ignored, as this is allowed in Core.

See #47632.

Coding Standards: Upgrade WPCS to 2.1.1.

Noteable changes:
- WPCS now throws warnings when non-strict comparisons are used. There are quite a few of them in Core. 🙃
- WPCS now detects and warns for assignments in loop conditions.

See #47632.

Coding Standards: Mark the handful of hook names with uppercase characters or hyphens as ignored.

See #47632.

Text Changes: Use consistent question wording in database connection error messages.

Props Presskopp.
See #44878.

Text Changes: Use consistent question wording for plugin and theme deletion confirmations.

Props johnjamesjacoby, Presskopp.
Fixes #44878.

Twenty Nineteen: Fix markup errors in `twentynineteen_add_ellipses_to_nav()`:

* Add missing i18n for `aria-label` attribute.
* Remove redundant screen reader text superseded by `aria-label`.
* Remove unnecessary `id` and `class` attributes.

Props afercia, chetan200891, ianbelanger.
Fixes #47067.

Twenty Nineteen: Adjust markup in `twentynineteen_add_ellipses_to_nav()` for better readability.

See #47067.

Twenty Nineteen: Update `package.json` with the latest package versions to pass `npm audit`.

Props netweb.
Fixes #47631.

Script Loader: Remove unnecessary `jquery` dependency for `wp-sanitize.js`.

The file is written in plain JavaScript.

Props sstoqnov.
Fixes #47324.

Bundled Themes: Remove extra semicolons from CSS files.

Props shashank3105, ianbelanger.
Fixes #47178.

Query: Make sure `$climits` variable in `WP_Query::get_posts()` is always defined to avoid a PHP notice.

Props juiiee8487, agengineering.
Fixes #47638.

Coding Standards: Fix the `Squiz.PHP.DisallowMultipleAssignments` violations in `wp-includes`.

See #47632.

Formatting: Revert the changes to `wpautop()` in [45585,45587].

See #27350.

Coding Standards: Fix the `Squiz.PHP.DisallowMultipleAssignments` violations in `tests`.

See #47632.

Formatting: Improve performance of `wpautop()` on large paragraphs.

Following [45585], older versions of PHP could segfault when attempting to autop paragraphs with 10,000+ characters.

Rather than having to negative lookahead for every character in the paragraph (which could run into recursion limits), we can quickly jump ahead to the next tag and start checking from there.

See #27350.