[5.x] Add support for whereHas() etc to query builders

src/Fields/Fieldtype.php

@@ -350,6 +350,11 @@ public function isRelationship(): bool
         return $this->relationship;
     }
 
+    public function relationshipQueryBuilder()
+    {
+        return false;
+    }
+
     public function toQueryableValue($value)
     {
         return $value;

src/Fieldtypes/Entries.php

@@ -354,6 +354,14 @@ protected function getItemsForPreProcessIndex($values): SupportCollection
             : $augmented->whereAnyStatus()->get();
     }
 
+    public function relationshipQueryBuilder()
+    {
+        $collections = $this->config('collections');
+
+        return Entry::query()
+            ->when($collections, fn ($query) => $query->whereIn('collection', $collections));
+    }
+
     public function filter()
     {
         return new EntriesFilter($this);

src/Fieldtypes/Terms.php

@@ -446,4 +446,12 @@ protected function getItemsForPreProcessIndex($values): Collection
 
         return $this->config('max_items') === 1 ? collect([$augmented]) : $augmented->get();
     }
+
+    public function relationshipQueryBuilder()
+    {
+        $taxonomies = $this->taxonomies();
+
+        return Term::query()
+            ->when($taxonomies, fn ($query) => $query->whereIn('taxonomy', $taxonomies));
+    }
 }

src/Fieldtypes/Users.php

@@ -217,4 +217,9 @@ public function filter()
     {
         return new UserFilter($this);
     }
+
+    public function relationshipQueryBuilder()
+    {
+        return User::query();
+    }
 }

src/Query/Builder.php

@@ -13,6 +13,8 @@
 
 abstract class Builder implements Contract
 {
+    use Traits\QueriesRelationships;
+
     protected $columns;
     protected $limit;
     protected $offset = 0;

src/Query/Traits/QueriesRelationships.php

@@ -0,0 +1,244 @@
+<?php
+
+namespace Statamic\Query\Traits;
+
+use Closure;
+use InvalidArgumentException;
+use Statamic\Support\Str;
+
+trait QueriesRelationships
+{
+    /**
+     * Add a relationship count / exists condition to the query.
+     *
+     * @param  string  $relation
+     * @param  string  $operator
+     * @param  int  $count
+     * @param  string  $boolean
+     * @return \Statamic\Query\Builder|static
+     *
+     * @throws \InvalidArgumentException
+     */
+    public function has($relation, $operator = '>=', $count = 1, $boolean = 'and', Closure $callback = null)
+    {
+        [$relationQueryBuilder, $relationField] = $this->getRelationQueryBuilderAndField($relation);
+
+        $maxItems = $relationField->config()['max_items'] ?? 0;
+        $negate = in_array($operator, ['!=', '<']);
+
+        if (! $callback) {
+            if ($maxItems == 1) {
+                $method = $boolean == 'and' ? 'whereNull' : 'orWhereNull';
+                if (! $negate) {
+                    $method = str_replace('Null', 'NotNull', $method);
+                }
+
+                return $this->$method($relation);
+            }
+
+            return $this->{$boolean == 'and' ? 'whereJsonLength' : 'orWhereJsonLength'}($relation, $operator, $count);
+        }
+
+        if ($count != 1) {
+            throw new InvalidArgumentException('Counting with subqueries in has clauses is not supported');
+        }
+
+        $ids = $relationQueryBuilder
+            ->where($callback)
+            ->get(['id'])
+            ->map(fn ($item) => Str::after($item->id(), '::'))
+            ->all();
+
+        if ($maxItems == 1) {
+            $method = $boolean == 'and' ? 'whereIn' : 'orWhereIn';
+            if ($negate) {
+                $method = str_replace('here', 'hereNot', $method);
+            }
+
+            return $this->$method($relation, $ids);
+        }
+
+        if (empty($ids)) {
+            return $this->{$boolean == 'and' ? 'whereJsonContains' : 'orWhereJsonContains'}($relation, ['']);
+        }
+
+        return $this->{$boolean == 'and' ? 'where' : 'orWhere'}(function ($subquery) use ($ids, $negate, $relation) {
+            foreach ($ids as $count => $id) {
+                $method = $count == 0 ? 'whereJsonContains' : 'orWhereJsonContains';
+                if ($negate) {
+                    $method = str_replace('Contains', 'DoesntContain', $method);
+                }
+
+                $subquery->$method($relation, [$id]);
+            }
+        });
+    }
+
+    /**
+     * Add a relationship count / exists condition to the query with an "or".
+     *
+     * @param  string  $relation
+     * @param  string  $operator
+     * @param  int  $count
+     * @return \Statamic\Query\Builder|static
+     */
+    public function orHas($relation, $operator = '>=', $count = 1)
+    {
+        return $this->has($relation, $operator, $count, 'or');
+    }
+
+    /**
+     * Add a relationship count / exists condition to the query.
+     *
+     * @param  string  $relation
+     * @param  string  $boolean
+     * @return \Statamic\Query\Builder|static
+     */
+    public function doesntHave($relation, $boolean = 'and', Closure $callback = null)
+    {
+        return $this->has($relation, '<', 1, $boolean, $callback);
+    }
+
+    /**
+     * Add a relationship count / exists condition to the query with an "or".
+     *
+     * @param  string  $relation
+     * @return \Statamic\Query\Builder|static
+     */
+    public function orDoesntHave($relation)
+    {
+        return $this->doesntHave($relation, 'or');
+    }
+
+    /**
+     * Add a relationship count / exists condition to the query with where clauses.
+     *
+     * @param  string  $relation
+     * @param  string  $operator
+     * @param  int  $count
+     * @return \Statamic\Query\Builder|static
+     */
+    public function whereHas($relation, Closure $callback = null, $operator = '>=', $count = 1)
+    {
+        return $this->has($relation, $operator, $count, 'and', $callback);
+    }
+
+    /**
+     * Add a relationship count / exists condition to the query with where clauses and an "or".
+     *
+     * @param  string  $relation
+     * @param  string  $operator
+     * @param  int  $count
+     * @return \Statamic\Query\Builder|static
+     */
+    public function orWhereHas($relation, Closure $callback = null, $operator = '>=', $count = 1)
+    {
+        return $this->has($relation, $operator, $count, 'or', $callback);
+    }
+
+    /**
+     * Add a relationship count / exists condition to the query with where clauses.
+     *
+     * @param  string  $relation
+     * @return \Statamic\Query\Builder|static
+     */
+    public function whereDoesntHave($relation, Closure $callback = null)
+    {
+        return $this->doesntHave($relation, 'and', $callback);
+    }
+
+    /**
+     * Add a relationship count / exists condition to the query with where clauses and an "or".
+     *
+     * @param  string  $relation
+     * @return \Statamic\Query\Builder|static
+     */
+    public function orWhereDoesntHave($relation, Closure $callback = null)
+    {
+        return $this->doesntHave($relation, 'or', $callback);
+    }
+
+    /**
+     * Add a basic where clause to a relationship query.
+     *
+     * @param  string  $relation
+     * @param  \Closure|string|array|\Illuminate\Contracts\Database\Query\Expression  $column
+     * @param  mixed  $operator
+     * @param  mixed  $value
+     * @return \Statamic\Query\Builder|static
+     */
+    public function whereRelation($relation, $column, $operator = null, $value = null)
+    {
+        return $this->whereHas($relation, function ($query) use ($column, $operator, $value) {
+            if ($column instanceof Closure) {
+                $column($query);
+            } else {
+                $query->where($column, $operator, $value);
+            }
+        });
+    }
+
+    /**
+     * Add an "or where" clause to a relationship query.
+     *
+     * @param  string  $relation
+     * @param  \Closure|string|array|\Illuminate\Contracts\Database\Query\Expression  $column
+     * @param  mixed  $operator
+     * @param  mixed  $value
+     * @return \Statamic\Query\Builder|static
+     */
+    public function orWhereRelation($relation, $column, $operator = null, $value = null)
+    {
+        return $this->orWhereHas($relation, function ($query) use ($column, $operator, $value) {
+            if ($column instanceof Closure) {
+                $column($query);
+            } else {
+                $query->where($column, $operator, $value);
+            }
+        });
+    }
+
+    /**
+     * Get the blueprints available to this query builder
+     *
+     * @return \Illuminate\Support\Collection
+     */
+    protected function getBlueprintsForRelations()
+    {
+        return collect();
+    }
+
+    /**
+     * Get the query builder and field for the relation we are querying (if they exist)
+     *
+     * @param  string  $relation
+     * @return \Statamic\Query\Builder
+     */
+    protected function getRelationQueryBuilderAndField($relation)
+    {
+        $relationField = $this->getBlueprintsForRelations()
+            ->flatMap(function ($blueprint) use ($relation) {
+                return $blueprint->fields()->all()->map(function ($field) use ($relation) {
+                    if ($field->handle() == $relation && $field->fieldtype()->isRelationship()) {
+                        return $field;
+                    }
+                })
+                    ->filter()
+                    ->values();
+            })
+            ->filter()
+            ->first();
+
+        if (! $relationField) {
+            throw new InvalidArgumentException("Relation {$relation} does not exist");
+        }
+
+        $queryBuilder = $relationField->fieldtype()->relationshipQueryBuilder();
+
+        if (! $queryBuilder) {
+            throw new InvalidArgumentException("Relation {$relation} does not support subquerying");
+        }
+
+        return [$queryBuilder, $relationField];
+    }
+}

src/Stache/Query/EntryQueryBuilder.php

@@ -131,4 +131,29 @@ protected function getWhereColumnKeyValuesByIndex($column)
             return $this->getWhereColumnKeysFromStore($collection, ['column' => $column]);
         });
     }
+
+    protected function getBlueprintsForRelations()
+    {
+        $wheres = collect($this->wheres);
+
+        $collections = $wheres->where('column', 'collection')
+            ->flatMap(function ($where) {
+                return $where['values'] ?? [$where['value']] ?? [];
+            })
+            ->unique();
+
+        if (! $collections->count()) {
+            $collections = Facades\Collection::all();
+        }
+
+        return $collections->flatMap(function ($collection) {
+            if (is_string($collection)) {
+                $collection = Facades\Collection::find($collection);
+            }
+
+            return $collection ? $collection->entryBlueprints() : false;
+        })
+            ->filter()
+            ->unique();
+    }
 }

src/Stache/Query/TermQueryBuilder.php

@@ -176,4 +176,21 @@ protected function getWhereColumnKeyValuesByIndex($column)
 
         return $items;
     }
+
+    protected function getBlueprintsForRelations()
+    {
+        $taxonomies = empty($this->taxonomies)
+            ? Facades\Taxonomy::handles()
+            : $this->taxonomies;
+
+        return $taxonomies->flatMap(function ($taxonomy) {
+            if (is_string($taxonomy)) {
+                $taxonomy = Facades\Taxonomy::find($taxonomy);
+            }
+
+            return $taxonomy ? $taxonomy->termBlueprints() : false;
+        })
+            ->filter()
+            ->unique();
+    }
 }

src/Stache/Query/UserQueryBuilder.php

@@ -3,6 +3,7 @@
 namespace Statamic\Stache\Query;
 
 use Statamic\Auth\UserCollection;
+use Statamic\Facades\User;
 
 class UserQueryBuilder extends Builder
 {
@@ -50,4 +51,9 @@ protected function getOrderKeyValuesByIndex()
             return [$orderBy->sort => $items];
         });
     }
+
+    protected function getBlueprintsForRelations()
+    {
+        return collect([User::make()->blueprint()]);
+    }
 }