From 1e0c3c5a7dfc5740bc678a7c0215e778ed87b5d7 Mon Sep 17 00:00:00 2001
From: JasonOA888 <jason@outland.art>
Date: Mon, 9 Mar 2026 17:35:19 +0800
Subject: [PATCH] fix(frontend): block deletion of an app's last revision

When a user tries to delete the last revision of an app from Playground,
the UI now prevents this action instead of leaving the app in a broken state.

Changes:
- Add isLastRevision check that counts total visible revisions
- Disable delete button when deleting would remove all revisions
- Show helpful message: Cannot delete the only revision. Delete the app instead.

Fixes #3892
---
 .../Modals/DeleteVariantModal/Content.tsx     | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/web/oss/src/components/Playground/Components/Modals/DeleteVariantModal/Content.tsx b/web/oss/src/components/Playground/Components/Modals/DeleteVariantModal/Content.tsx
index 06f83f1967..f9ab30fa79 100644
--- a/web/oss/src/components/Playground/Components/Modals/DeleteVariantModal/Content.tsx
+++ b/web/oss/src/components/Playground/Components/Modals/DeleteVariantModal/Content.tsx
@@ -174,6 +174,17 @@ const DeleteVariantContent = ({revisionIds, forceVariantIds = [], onClose}: Prop
     const totalSelectedCount = uniqueRevisionIds.length
     const isBulkDelete = deletionPlan.variants.length > 0 || totalSelectedCount > 1
 
+    // Check if this would delete the last revision of the app
+    const isLastRevision = useMemo(() => {
+        // Count total visible revisions across all variants
+        let totalRevisions = 0
+        Object.values(variantGroups).forEach((group) => {
+            totalRevisions += group.totalIds.length
+        })
+        // If we're deleting all revisions, this is the last one
+        return totalRevisions > 0 && totalSelectedCount >= totalRevisions
+    }, [variantGroups, totalSelectedCount])
+
     const onDeleteVariant = useCallback(async () => {
         setIsMutating(true)
         try {
@@ -277,13 +288,19 @@ const DeleteVariantContent = ({revisionIds, forceVariantIds = [], onClose}: Prop
                     type="primary"
                     danger
                     loading={isMutating}
-                    disabled={isMutating || totalSelectedCount === 0}
+                    disabled={isMutating || totalSelectedCount === 0 || isLastRevision}
                     icon={<Trash size={14} />}
                     onClick={onDeleteVariant}
+                    title={isLastRevision ? "Cannot delete the only revision. Delete the app instead." : undefined}
                 >
                     {isBulkDelete ? "Delete selected" : "Delete"}
                 </Button>
             </div>
+            {isLastRevision && (
+                <Text type="secondary" className="text-center">
+                    Cannot delete the only revision. Delete the app instead.
+                </Text>
+            )}
         </section>
     )
 }