From c97cf604ab4a902d89fe873b90dbeb9dabc940eb Mon Sep 17 00:00:00 2001
From: "claude[bot]" <209825114+claude[bot]@users.noreply.github.com>
Date: Mon, 9 Mar 2026 08:19:33 +0000
Subject: [PATCH] fix: guard iteration picker VirtualList against empty items
 array (#8273)

When a flow loops over an empty array, the VirtualList component crashes
trying to access index 0 in an empty range. Add a guard to only render
VirtualList when items.length > 0, showing a "No iterations" message
otherwise.

Fixes #8272

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: windmill-internal-app[bot] <windmill-internal-app[bot]@users.noreply.github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
---
 frontend/src/lib/components/flows/map/FlowJobsMenu.svelte | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/frontend/src/lib/components/flows/map/FlowJobsMenu.svelte b/frontend/src/lib/components/flows/map/FlowJobsMenu.svelte
index c945454e52..f6cd1607da 100644
--- a/frontend/src/lib/components/flows/map/FlowJobsMenu.svelte
+++ b/frontend/src/lib/components/flows/map/FlowJobsMenu.svelte
@@ -142,6 +142,7 @@
 
 					<div class="max-h-[300px]">
 						{#key items}
+							{#if items.length > 0}
 							<VirtualList height={300} width="100%" itemCount={items.length} itemSize={24}>
 								{#snippet header()}{/snippet}
 								{#snippet footer()}{/snippet}
@@ -170,6 +171,9 @@
 									</div>
 								{/snippet}
 							</VirtualList>
+							{:else}
+								<div class="text-xs text-tertiary py-2 px-2">No iterations</div>
+							{/if}
 						{/key}
 
 						<!-- {#each flowJobs ?? [] as id, idx (id)}