Add oxlint rule to catch thrown un-awaited redirect helpers

.oxlintrc.json

@@ -1,6 +1,7 @@
 {
   "$schema": "./node_modules/oxlint/configuration_schema.json",
   "plugins": ["typescript", "import", "react"],
+  "jsPlugins": ["./oxlint-plugins/no-thrown-unawaited-redirect.mjs"],
   "ignorePatterns": [
     "**/dist/**",
     "**/build/**",
@@ -31,6 +32,7 @@
     "import/no-duplicates": "error",
     "import/namespace": "off",
     "react-hooks/exhaustive-deps": "off",
-    "react-hooks/rules-of-hooks": "off"
+    "react-hooks/rules-of-hooks": "off",
+    "trigger/no-thrown-unawaited-redirect": "error"
   }
 }

apps/webapp/app/routes/_app.orgs.$organizationSlug.projects.$projectParam.env.$envParam.branches/route.tsx

@@ -134,7 +134,7 @@ export async function action({ request, params }: ActionFunctionArgs) {
     );
 
     if (!project) {
-      throw redirectWithErrorMessage(redirectPath, request, "Project not found");
+      throw await redirectWithErrorMessage(redirectPath, request, "Project not found");
     }
 
     const currentPlan = await getCurrentPlan(project.organizationId);

apps/webapp/app/routes/_app.orgs.$organizationSlug.projects.$projectParam.env.$envParam.concurrency/route.tsx

@@ -155,7 +155,7 @@ export const action = async ({ request, params }: ActionFunctionArgs) => {
   );
 
   if (!project) {
-    throw redirectWithErrorMessage(redirectPath, request, "Project not found");
+    throw await redirectWithErrorMessage(redirectPath, request, "Project not found");
   }
 
   const formData = await request.formData();

apps/webapp/app/routes/_app.orgs.$organizationSlug.projects.$projectParam.env.$envParam.regions/route.tsx

@@ -103,14 +103,14 @@ export const action = async ({ request, params }: ActionFunctionArgs) => {
   );
 
   if (!project) {
-    throw redirectWithErrorMessage(redirectPath, request, "Project not found");
+    throw await redirectWithErrorMessage(redirectPath, request, "Project not found");
   }
 
   const formData = await request.formData();
   const parsedFormData = FormSchema.safeParse(Object.fromEntries(formData));
 
   if (!parsedFormData.success) {
-    throw redirectWithErrorMessage(redirectPath, request, "No region specified");
+    throw await redirectWithErrorMessage(redirectPath, request, "No region specified");
   }
 
   const service = new SetDefaultRegionService();

apps/webapp/app/routes/resources.orgs.$organizationSlug.select-plan.tsx

@@ -80,7 +80,7 @@ export const action = dashboardAction(
     });
 
     if (!organization) {
-      throw redirectWithErrorMessage(form.callerPath, request, "Organization not found");
+      throw await redirectWithErrorMessage(form.callerPath, request, "Organization not found");
     }
 
     let payload: SetPlanBody;
@@ -139,7 +139,7 @@ export const action = dashboardAction(
       }
       case "paid": {
         if (form.planCode === undefined) {
-          throw redirectWithErrorMessage(form.callerPath, request, "Not a valid plan");
+          throw await redirectWithErrorMessage(form.callerPath, request, "Not a valid plan");
         }
         payload = {
           type: "paid" as const,

apps/webapp/app/routes/vercel.onboarding.tsx

@@ -69,7 +69,7 @@ export async function loader({ request }: LoaderFunctionArgs) {
 
   if (!params.success) {
     logger.error("Invalid params for Vercel onboarding", { error: params.error });
-    throw redirectWithErrorMessage(
+    throw await redirectWithErrorMessage(
       "/",
       request,
       "Invalid installation parameters. Please try again from Vercel."
@@ -89,7 +89,7 @@ export async function loader({ request }: LoaderFunctionArgs) {
 
   if (!params.data.code) {
     logger.error("Missing code parameter for Vercel onboarding");
-    throw redirectWithErrorMessage(
+    throw await redirectWithErrorMessage(
       "/",
       request,
       "Invalid installation parameters. Please try again from Vercel."
@@ -151,7 +151,11 @@ export async function loader({ request }: LoaderFunctionArgs) {
         organizationId: params.data.organizationId,
         userId,
       });
-      throw redirectWithErrorMessage("/", request, "Organization not found. Please try again.");
+      throw await redirectWithErrorMessage(
+        "/",
+        request,
+        "Organization not found. Please try again."
+      );
     }
 
     return typedjson({

oxlint-plugins/no-thrown-unawaited-redirect.mjs

@@ -0,0 +1,106 @@
+/**
+ * oxlint custom rule: no-thrown-unawaited-redirect
+ *
+ * Catches `throw someRedirectHelper(...)` where the helper is an *async* function
+ * that returns a Promise<Response> (e.g. `redirectWithErrorMessage`). Throwing the
+ * un-awaited call throws a *pending Promise* instead of a Response, so Remix renders
+ * the route's error boundary instead of performing the redirect.
+ *
+ * Correct forms are:
+ *   - `throw await redirectWithErrorMessage(...)`
+ *   - `return redirectWithErrorMessage(...)`
+ *
+ * Note: the plain synchronous `redirect(...)` from `remix-typedjson` returns a
+ * `Response` directly, so `throw redirect(...)` is the intended Remix control-flow
+ * pattern and is intentionally NOT flagged.
+ */
+
+// Async redirect helpers that return a Promise. Extend this list as new async
+// redirect helpers are added.
+const ASYNC_REDIRECT_HELPERS = new Set([
+  "redirectWithSuccessMessage",
+  "redirectWithErrorMessage",
+  "redirectBackWithErrorMessage",
+  "redirectBackWithSuccessMessage",
+  "redirectWithImpersonation",
+]);
+
+const FUNCTION_TYPES = new Set([
+  "ArrowFunctionExpression",
+  "FunctionDeclaration",
+  "FunctionExpression",
+]);
+
+function isInsideAsyncFunction(node, sourceCode) {
+  const ancestors = sourceCode.getAncestors(node);
+
+  for (let index = ancestors.length - 1; index >= 0; index--) {
+    const ancestor = ancestors[index];
+
+    if (FUNCTION_TYPES.has(ancestor.type)) {
+      return ancestor.async;
+    }
+  }
+
+  return false;
+}
+
+/** @type {import("eslint").Rule.RuleModule} */
+const noThrownUnawaitedRedirect = {
+  meta: {
+    type: "problem",
+    docs: {
+      description:
+        "Disallow throwing an un-awaited async redirect helper (throws a pending Promise instead of a Response).",
+    },
+    fixable: "code",
+    messages: {
+      unawaited:
+        'Throwing an un-awaited "{{name}}()" throws a pending Promise (Remix renders the error boundary instead of redirecting). Use "throw await {{name}}()" or "return {{name}}()".',
+    },
+    schema: [],
+  },
+  create(context) {
+    return {
+      ThrowStatement(node) {
+        const argument = node.argument;
+
+        // Already awaited (`throw await helper()`) -> fine.
+        if (!argument || argument.type === "AwaitExpression") {
+          return;
+        }
+
+        // Only care about direct calls: `throw helper(...)`.
+        if (argument.type !== "CallExpression") {
+          return;
+        }
+
+        const callee = argument.callee;
+        if (callee.type !== "Identifier" || !ASYNC_REDIRECT_HELPERS.has(callee.name)) {
+          return;
+        }
+
+        const canAutofix = isInsideAsyncFunction(node, context.sourceCode);
+
+        context.report({
+          node: argument,
+          messageId: "unawaited",
+          data: { name: callee.name },
+          fix: canAutofix ? (fixer) => fixer.insertTextBefore(argument, "await ") : undefined,
+        });
+      },
+    };
+  },
+};
+
+/** @type {import("eslint").ESLint.Plugin} */
+const plugin = {
+  meta: {
+    name: "trigger",
+  },
+  rules: {
+    "no-thrown-unawaited-redirect": noThrownUnawaitedRedirect,
+  },
+};
+
+export default plugin;