ENH Use allowed view button for readonly GridField

src/Forms/GridField/GridField.php

@@ -276,9 +276,18 @@ public function performReadonlyTransformation()
             }
         }
 
-        // If the edit button has been removed, replace it with a view button
+        // If the edit button has been removed, replace it with a view button if one is allowed
         if ($hadEditButton && !$copyConfig->getComponentByType(GridFieldViewButton::class)) {
-            $copyConfig->addComponent(GridFieldViewButton::create());
+            $viewButtonClass = null;
+            foreach ($allowedComponents as $componentClass) {
+                if (is_a($componentClass, GridFieldViewButton::class, true)) {
+                    $viewButtonClass = $componentClass;
+                    break;
+                }
+            }
+            if ($viewButtonClass) {
+                $copyConfig->addComponent($viewButtonClass::create());
+            }
         }
 
         $copy->extend('afterPerformReadonlyTransformation', $this);

tests/php/Forms/GridField/GridFieldReadonlyTest.php

@@ -20,6 +20,8 @@
 use SilverStripe\Forms\Tests\GridField\GridFieldTest\Team;
 use SilverStripe\Dev\SapphireTest;
 use SilverStripe\Forms\GridField\GridField;
+use SilverStripe\Forms\GridField\GridFieldViewButton;
+use SilverStripe\Forms\Tests\GridField\GridFieldReadonlyTest\GridFieldViewButtonReplacement;
 use SilverStripe\Versioned\VersionedGridFieldState\VersionedGridFieldState;
 
 class GridFieldReadonlyTest extends SapphireTest
@@ -31,11 +33,28 @@ class GridFieldReadonlyTest extends SapphireTest
         Cheerleader::class,
     ];
 
+    public function provideReadOnlyTransformation(): array
+    {
+        return [
+            [
+                'viewButtonClass' => null,
+            ],
+            [
+                'viewButtonClass' => GridFieldViewButton::class,
+            ],
+            [
+                'viewButtonClass' => GridFieldViewButtonReplacement::class,
+            ],
+        ];
+    }
+
     /**
      * The CMS can set the value of a GridField to be a hasMany relation, which needs a readonly state.
      * This test ensures GridField has a readonly transformation.
+     *
+     * @dataProvider provideReadOnlyTransformation
      */
-    public function testReadOnlyTransformation()
+    public function testReadOnlyTransformation(?string $viewButtonClass)
     {
         // Build a hasMany Relation via getComponents like ModelAdmin does.
         $components = Team::get_one(Team::class)
@@ -67,6 +86,18 @@ public function testReadOnlyTransformation()
             $gridConfig
         );
 
+        if ($viewButtonClass !== GridFieldViewButton::class) {
+            $allowedComponents = $gridConfig->getReadonlyComponents();
+            $viewButtonIndex = array_search(GridFieldViewButton::class, $allowedComponents);
+            if ($viewButtonIndex !== false) {
+                unset($readonlyComponents[$viewButtonIndex]);
+            }
+            if ($viewButtonClass !== null) {
+                $allowedComponents[] = $viewButtonClass;
+            }
+            $gridField->setReadonlyComponents($allowedComponents);
+        }
+
         // Model Admin sets the value of the GridField directly to the relation, which doesn't have a forTemplate()
         // function, if we rely on FormField to render into a ReadonlyField we'll get an error as HasManyRelation
         // doesn't have a forTemplate() function.

tests/php/Forms/GridField/GridFieldReadonlyTest/GridFieldViewButtonReplacement.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace SilverStripe\Forms\Tests\GridField\GridFieldReadonlyTest;
+
+use SilverStripe\Dev\TestOnly;
+use SilverStripe\Forms\GridField\GridFieldViewButton;
+
+class GridFieldViewButtonReplacement extends GridFieldViewButton implements TestOnly
+{
+
+}