Added doc for TaxonomyNoEntries

Author: mnocon

code_samples/search/content/taxonomy_no_entries_criterion.php

@@ -0,0 +1,18 @@
+<?php
+
+declare(strict_types=1);
+
+use Ibexa\Contracts\Core\Repository\Values\Content\Query;
+use Ibexa\Contracts\Core\Repository\Values\Content\Query\Criterion\ContentTypeIdentifier;
+use Ibexa\Contracts\Core\Repository\Values\Content\Query\Criterion\LogicalAnd;
+use Ibexa\Contracts\Taxonomy\Search\Query\Criterion\TaxonomyNoEntries;
+
+$query = new Query();
+$query->query = new LogicalAnd([
+    new TaxonomyNoEntries('tags'),
+    new ContentTypeIdentifier('article'),
+    ]
+);
+
+/** @var \Ibexa\Contracts\Core\Repository\SearchService $searchService */
+$results = $searchService->findContent($query);

docs/content_management/taxonomy/taxonomy_api.md

@@ -71,3 +71,15 @@ and a `position` parameter, which is either `TaxonomyServiceInterface::MOVE_POSI
 
     Taxonomy entry management functions triggers events you can listen to.
     For more information, see [Taxonomy events](taxonomy_events.md).
+
+## Search
+
+You can search for content based on its taxonomy entry assignments by using the standard
+[`SearchService`](search_api.md) with taxonomy-specific Search Criteria:
+
+| Criterion | Description |
+|---|---|
+| [TaxonomyEntryId](taxonomy_entry_id.md) | Find content assigned to a specific taxonomy entry |
+| [TaxonomyNoEntries](taxonomy_no_entries.md) | Find content that has no entries assigned from a given taxonomy |
+
+You can also use the [TaxonomyEntryId Aggregation](taxonomyentryid_aggregation.md) to count content items per taxonomy entry.

docs/search/criteria_reference/isfieldempty_criterion.md

@@ -18,6 +18,9 @@ The `IsFieldEmpty` Criterion isn't available in [Repository filtering](search_ap
 
 The Richtext field type (`ezrichtext`) isn't searchable in the Legacy search engine.
 
+The `IsFieldEmpty` criterion doesn't work for [Taxonomy entry assignment](taxonomyentryassignmentfield.md) fields.
+For this use case, use [`TaxonomyNoEntries`](taxonomy_no_entries.md) instead.
+
 ## Example
 
 ### PHP

docs/search/criteria_reference/search_criteria_reference.md

@@ -68,6 +68,7 @@ Due to this storage limitation, searching content using the Country field type o
 | [Sibling](sibling_criterion.md)                               | Locations that are children of the same parent                                              | ✔       | ✔        | ✔  |          |
 | [Subtree](subtree_criterion.md)                               | Location subtree                                                                            | ✔       | ✔        | ✔  |          |
 | [TaxonomyEntryId](taxonomy_entry_id.md)                       | Content tagged with Entry ID                                                                | ✔       | ✔        | ✔  |          |
+| [TaxonomyNoEntries](taxonomy_no_entries.md)                   | Content with no entries assigned from a given taxonomy                                      | ✔       | ✔        | ✔  |          |
 | [UserEmail](useremail_criterion.md)                           | Email address of a User account                                                             | ✔       | ✔        | ✔  |          |
 | [UserId](userid_criterion.md)                                 | User ID                                                                                     | ✔       | ✔        | ✔  |          |
 | [UserLogin](userlogin_criterion.md)                           | User login                                                                                  | ✔       | ✔        | ✔  |          |

docs/search/criteria_reference/taxonomy_no_entries.md

@@ -0,0 +1,29 @@
+---
+description: TaxonomyNoEntries Search Criterion
+---
+
+# TaxonomyNoEntries Criterion
+
+The [`TaxonomyNoEntries` Search Criterion](https://example.com/api/php_api/php_api_reference/classes/Ibexa-Contracts-Taxonomy-Search-Query-Criterion-TaxonomyNoEntries.html) searches for content that has no entries assigned from the specified [taxonomy](taxonomy.md).
+
+Use it when you need to find content items to which no taxonomy entries have been assigned (for example, articles without tags).
+It is available for all supported search engines and in [repository filtering](search_api.md#repository-filtering)
+
+## Arguments
+
+- `taxonomy` - `string` representing the identifier of the taxonomy (for example, `tags` or `categories`)
+
+## Example
+
+### PHP
+
+The following example searches for articles that have no entries assigned in the `tags` taxonomy:
+
+```php hl_lines="11-14"
+[[= include_file('code_samples/search/content/taxonomy_no_entries_criterion.php') =]]
+```
+
+The criteria limit the results to content matching all of the conditions listed below:
+
+- content has no entries assigned in the `tags` taxonomy
+- content type is `article`

mkdocs.yml

@@ -568,6 +568,7 @@ nav:
             - Sibling: search/criteria_reference/sibling_criterion.md
             - Subtree: search/criteria_reference/subtree_criterion.md
             - TaxonomyEntryID: search/criteria_reference/taxonomy_entry_id.md
+            - TaxonomyNoEntries: search/criteria_reference/taxonomy_no_entries.md
             - UserEmail: search/criteria_reference/useremail_criterion.md
             - UserId: search/criteria_reference/userid_criterion.md
             - UserLogin: search/criteria_reference/userlogin_criterion.md