From 53969121d20eab0f0d8a308761d493ab4e87732c Mon Sep 17 00:00:00 2001
From: brandonkelly <brandon@pixelandtonic.com>
Date: Mon, 22 Apr 2019 14:52:14 -0700
Subject: [PATCH] :empty: & :notempty: Matrix field query params must account
 for soft-deleted blocks

Resolves #4161
---
 CHANGELOG-v3.md       |  1 +
 src/fields/Matrix.php | 21 +++++++++++++++------
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG-v3.md b/CHANGELOG-v3.md
index 07edd2e2794..9b21805dd80 100644
--- a/CHANGELOG-v3.md
+++ b/CHANGELOG-v3.md
@@ -11,6 +11,7 @@
 - Fixed an error where re-saving a site would reset its sorting order. ([#4147](https://github.com/craftcms/cms/issues/4147))
 - Fixed a SQL error that could occur when updating to Craft 3.1. ([#3663](https://github.com/craftcms/cms/issues/3663))
 - Fixed an error that occurred when an SVG with `/` characters in its `id` attributes was passed to the `svg()` Twig function. ([#4155](https://github.com/craftcms/cms/issues/4155))
+- Fixed a bug where passing `:empty:` or `:notempty:` to a Matrix field param on an element query could return incorrect results for fields that had soft-deleted blocks. ([#4161](https://github.com/craftcms/cms/issues/4161))
 - Fixed a bug where Craft wasn’t returning a `1` exit code for console requests if the server was running under PHP 7. ([#4153](https://github.com/craftcms/cms/issues/4153))
 - Fixed a bug where `craft\services\Elements::duplicateElements()` would only ignore non-safe attributes passed to the `$newAttributes` argument.
 - Fixed a bug where `craft\elements\db\ElementQuery::exists()` and `offsetExists()` were ignoring cached query results.
diff --git a/src/fields/Matrix.php b/src/fields/Matrix.php
index 14ea4f55bd9..1946f9d48d5 100644
--- a/src/fields/Matrix.php
+++ b/src/fields/Matrix.php
@@ -437,13 +437,22 @@ public function modifyElementsQuery(ElementQueryInterface $query, $value)
         }
 
         if ($value === ':notempty:' || $value === ':empty:') {
-            $alias = 'matrixblocks_' . $this->handle;
-            $operator = ($value === ':notempty:' ? '!=' : '=');
+            $ns = $this->handle . '_' . StringHelper::randomString(5);
+            $condition = ['exists', (new Query())
+                ->from(TableName::MATRIXBLOCKS . " matrixblocks_$ns")
+                ->innerJoin(TableName::ELEMENTS . " elements_$ns", "[[elements_$ns.id]] = [[matrixblocks_$ns.id]]")
+                ->where("[[matrixblocks_$ns.ownerId]] = [[elements.id]]")
+                ->andWhere([
+                    "matrixblocks_$ns.fieldId" => $this->id,
+                    "elements_$ns.dateDeleted" => null,
+                ])
+            ];
 
-            $query->subQuery->andWhere(
-                "(select count([[{$alias}.id]]) from {{%matrixblocks}} {{{$alias}}} where [[{$alias}.ownerId]] = [[elements.id]] and [[{$alias}.fieldId]] = :fieldId) {$operator} 0",
-                [':fieldId' => $this->id]
-            );
+            if ($value === ':notempty:') {
+                $query->subQuery->andWhere($condition);
+            } else {
+                $query->subQuery->andWhere(['not', $condition]);
+            }
         } else if ($value !== null) {
             return false;
         }