From 08cbe0ad646302052747acbc259666c8e57cf29c Mon Sep 17 00:00:00 2001
From: "Calum H. (IMB11)" <contact@cal.engineer>
Date: Sat, 14 Mar 2026 23:08:13 +0000
Subject: [PATCH] fix: switching vers fix

---
 apps/app-frontend/src/pages/instance/Mods.vue | 37 +++++++++++++++++--
 1 file changed, 34 insertions(+), 3 deletions(-)

diff --git a/apps/app-frontend/src/pages/instance/Mods.vue b/apps/app-frontend/src/pages/instance/Mods.vue
index 15a015cb19..a6e3316983 100644
--- a/apps/app-frontend/src/pages/instance/Mods.vue
+++ b/apps/app-frontend/src/pages/instance/Mods.vue
@@ -92,6 +92,7 @@ import { get_project_versions, get_version } from '@/helpers/cache.js'
 import { profile_listener } from '@/helpers/events.js'
 import {
 	add_project_from_path,
+	add_project_from_version,
 	duplicate,
 	edit,
 	get,
@@ -351,6 +352,34 @@ async function updateProject(mod: ContentItem) {
 	}
 }
 
+async function switchProjectVersion(mod: ContentItem, version: Labrinth.Versions.v2.Version) {
+	try {
+		await remove_project(props.instance.path, mod.file_path!)
+		const newPath = await add_project_from_version(props.instance.path, version.id)
+
+		const profile = await get(props.instance.path).catch(handleError)
+		if (profile) {
+			await installVersionDependencies(profile, version).catch(handleError)
+		}
+
+		mod.file_path = newPath
+		if (mod.version) {
+			mod.version.id = version.id
+			mod.version.version_number = version.version_number
+		}
+
+		trackEvent('InstanceProjectSwitchVersion', {
+			loader: props.instance.loader,
+			game_version: props.instance.game_version,
+			id: mod.project?.id,
+			name: mod.project?.title ?? mod.file_name,
+			project_type: mod.project_type,
+		})
+	} catch (err) {
+		handleError(err as Error)
+	}
+}
+
 async function handleUpdate(id: string) {
 	const item = projects.value.find((p) => p.file_name === id)
 	if (!item?.has_update || !item.project?.id || !item.version?.id) return
@@ -570,9 +599,11 @@ async function handleModalUpdate(
 	} else if (updatingProject.value) {
 		const mod = updatingProject.value
 
-		mod.update_version_id = selectedVersion.id
-
-		await updateProject(mod)
+		if (mod.has_update && mod.update_version_id === selectedVersion.id) {
+			await updateProject(mod)
+		} else {
+			await switchProjectVersion(mod, selectedVersion)
+		}
 
 		resetUpdateState()
 	}