Clear the Image field to NULL, not to the 0 the constraint refuses

packages/web/management/languages/de_DE.UTF-8/LC_MESSAGES/messages.po

@@ -9271,6 +9271,9 @@ msgstr "Fehler beim Erstellen eines Tasks"
 msgid "The current user is invalid."
 msgstr "Task-Typ ist nicht gültig"
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/en_US.UTF-8/LC_MESSAGES/messages.po

@@ -9280,6 +9280,9 @@ msgstr "Failed to create task"
 msgid "The current user is invalid."
 msgstr "Task type is not valid"
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/es_ES.UTF-8/LC_MESSAGES/messages.po

@@ -9443,6 +9443,9 @@ msgstr "No se pudo crear la tarea"
 msgid "The current user is invalid."
 msgstr "tipo de tarea no es válida"
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/eu_ES.UTF-8/LC_MESSAGES/messages.po

@@ -9272,6 +9272,9 @@ msgstr "Fehler beim Erstellen eines Tasks"
 msgid "The current user is invalid."
 msgstr "Task-Typ ist nicht gültig"
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/fr_FR.UTF-8/LC_MESSAGES/messages.po

@@ -9265,6 +9265,9 @@ msgstr "Impossible de créer la tâche"
 msgid "The current user is invalid."
 msgstr "Type de tâche n'est pas valide"
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/it_IT.UTF-8/LC_MESSAGES/messages.po

@@ -8986,6 +8986,9 @@ msgstr "Impossibile creare un'attività"
 msgid "The current user is invalid."
 msgstr "Tipo di attività non è valido"
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/ja_JP.UTF-8/LC_MESSAGES/messages.po

@@ -8929,6 +8929,9 @@ msgstr "タスクの作成に失敗しました"
 msgid "The current user is invalid."
 msgstr ""
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/messages.pot

@@ -7905,6 +7905,9 @@ msgstr ""
 msgid "The current user is invalid."
 msgstr ""
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/pt_BR.UTF-8/LC_MESSAGES/messages.po

@@ -9267,6 +9267,9 @@ msgstr "Falha ao criar tarefa"
 msgid "The current user is invalid."
 msgstr "tipo de tarefa não é válido"
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/management/languages/zh_CN.UTF-8/LC_MESSAGES/messages.po

@@ -9267,6 +9267,9 @@ msgstr "无法创建任务"
 msgid "The current user is invalid."
 msgstr "任务类型无效"
 
+msgid "The database refused the update; nothing was changed"
+msgstr ""
+
 msgid "The default printer for hosts in this group. A host that has its own default keeps it."
 msgstr ""
 

packages/web/src/Pages/HostManagement.php

@@ -4226,9 +4226,18 @@ private function massEditSelection()
     private function massEditCoreFields()
     {
         return [
+            // NULL, not 0. `hosts`.`hostImage` carries a foreign key to
+            // `images`.`imageID` (ADR 0031, schema-constraints.php:145) and
+            // 0 is not exempt from a constraint just because it looks like
+            // an absence -- there is no image with id 0, so clearing to 0 is
+            // rejected outright and the whole mass edit fails. The column is
+            // nullable and the reconciler already swept every legacy 0 to
+            // NULL, so NULL is what "no image" actually IS on any 1.6
+            // database. Verified against a live install: 77 hosts hold NULL
+            // and none holds 0.
             'image' => [
                 'field' => 'imageID',
-                'empty' => 0,
+                'empty' => null,
                 'label' => _('Image'),
                 'kind' => 'image',
                 'tab' => 'general'
@@ -5143,8 +5152,18 @@ public function massEditPost()
                 // non-empty because an UPDATE with no assignments is either
                 // a syntax error or, worse, a statement whose WHERE is the
                 // only part left.
-                self::getClass('HostManager')
-                    ->update(['id' => $hosts], '', $updates);
+                // The return value is CHECKED. perform_update() answers
+                // false and writes a fault rather than throwing, so ignoring
+                // it reported "Updated 1 field(s) on 86 host(s)" for a write
+                // the database had refused -- which is how a clear that
+                // never landed reads as a clear that did.
+                if (!self::getClass('HostManager')
+                    ->update(['id' => $hosts], '', $updates)
+                ) {
+                    throw new \Exception(
+                        _('The database refused the update; nothing was changed')
+                    );
+                }
                 $affected = count($hosts);
             }
             // Row-backed fields count toward the same affectedCount: one

packages/web/src/Util/MassEdit.php

@@ -231,8 +231,11 @@ public static function resolveComposite(array $keys, $actions, $values)
      * @param array $resolved output of resolve()
      * @param array $spec     key => ['field' => <FOGController field name>,
      *                        'empty' => <what CLEAR writes, default ''>].
-     *                        A key absent from the spec is skipped: the spec
-     *                        is what says a key may touch a column at all.
+     *                        `empty` may be null, and null is written as
+     *                        NULL rather than treated as absent -- that is
+     *                        what a column with a foreign key needs. A key
+     *                        absent from the spec is skipped: the spec is
+     *                        what says a key may touch a column at all.
      *
      * @return array field name => value, ready for a manager update(). EMPTY
      *               when nothing was set or cleared -- and an empty map must
@@ -260,11 +263,23 @@ public static function columnUpdates(array $resolved, array $spec)
                 $updates[$spec[$key]['field']] = $instruction['value'];
             } elseif (self::CLEAR === $action) {
                 // Per field, because "empty" is not one value. A varchar
-                // column clears to '', an int foreign key to 0; writing ''
-                // into an int column stores 0 on a permissive server and
-                // errors on a strict one, so the answer belongs in the spec
-                // rather than in a cast here.
-                $updates[$spec[$key]['field']] = $spec[$key]['empty'] ?? '';
+                // column clears to '', a plain int to 0, and a column
+                // carrying a FOREIGN KEY to null -- 0 is not exempt from a
+                // constraint, so clearing `hosts`.`hostImage` to 0 is
+                // rejected outright unless an image with id 0 exists, which
+                // none does. The answer belongs in the spec rather than in a
+                // cast here.
+                //
+                // array_key_exists, NOT `?? ''`. Null is the whole point for
+                // the foreign-key case and `??` treats it as absent, so the
+                // coalesce silently turned every intended NULL back into ''
+                // -- which an int column then stores as 0, i.e. exactly the
+                // value that fails. A spec that genuinely omits `empty`
+                // still gets ''.
+                $updates[$spec[$key]['field']] =
+                    array_key_exists('empty', $spec[$key])
+                    ? $spec[$key]['empty']
+                    : '';
             }
         }