handle OSS onboarding error gracefully (#8459)

* fix: handle OSS onboarding error gracefully in setup wizard

When creating a custom admin account fails on OSS builds (Enterprise-only
feature), show a helpful dialog instead of a generic error, guiding the
user to continue with default credentials.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: use more precise error check for OSS account creation

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: correct error message — not an EE feature, just not implemented in OSS

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: remove misleading "change from user settings" since set_password is also OSS-stubbed

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* fix: move default credentials info to frontend dialog only

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

backend/windmill-api/src/users_oss.rs

@@ -38,7 +38,7 @@ pub async fn create_user(
     mut _nu: NewUser,
 ) -> Result<(StatusCode, String)> {
     Err(Error::internal_err(
-        "Not implemented in Windmill's Open Source repository".to_string(),
+        "User creation is not implemented in the open-source version.".to_string(),
     ))
 }
 

frontend/src/routes/(root)/(logged)/user/(user)/instance_settings/+page.svelte

@@ -84,6 +84,8 @@
 	let enableHubSync = $state(true)
 	let accountSubmitting = $state(false)
 	let accountError = $state('')
+	let showOssAccountDialog = $state(false)
+	let ossAccountError = $state('')
 
 	// --- Resource type sync (triggered on entering account step) ---
 	let rtSyncStatus: 'idle' | 'loading' | 'success' | 'error' = $state('idle')
@@ -316,7 +318,13 @@
 					)
 			)
 		} catch (e: any) {
-			accountError = e?.body?.message || e?.body || e?.message || 'An error occurred'
+			const msg = e?.body?.message || e?.body || e?.message || 'An error occurred'
+			if (typeof msg === 'string' && msg.includes('User creation is not implemented in the open-source version')) {
+				ossAccountError = msg
+				showOssAccountDialog = true
+			} else {
+				accountError = msg
+			}
 		} finally {
 			accountSubmitting = false
 		}
@@ -639,3 +647,37 @@
 		</div>
 	</ConfirmationModal>
 {/if}
+
+{#if showOssAccountDialog}
+	<ConfirmationModal
+		open={showOssAccountDialog}
+		title="Not available in open-source"
+		confirmationText="Continue with default credentials"
+		on:canceled={() => {
+			showOssAccountDialog = false
+		}}
+		on:confirmed={() => {
+			showOssAccountDialog = false
+			sendUserToast('Setup complete. Please log in with the default credentials.')
+			goto(
+				'/user/logout?rd=' +
+					encodeURIComponent(
+						'/user/login?email=' +
+							encodeURIComponent('admin@windmill.dev') +
+							'&password=' +
+							encodeURIComponent('changeme')
+					)
+			)
+		}}
+	>
+		<div class="flex flex-col w-full space-y-4">
+			<Alert type="error" title="Backend error">
+				{ossAccountError}
+			</Alert>
+			<span>
+				Click "Continue" to finish setup and log in with the default credentials
+				(admin@windmill.dev / changeme).
+			</span>
+		</div>
+	</ConfirmationModal>
+{/if}