Prevent dep optimizer race condition

.changeset/great-clocks-judge.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes a race condition where the Vite dep optimizer could lose React dependencies in dev mode when using Astro Actions

packages/astro/src/vite-plugin-integrations-container/index.ts

@@ -1,5 +1,5 @@
 import type { PluginContext } from 'rollup';
-import type { Plugin as VitePlugin } from 'vite';
+import type { Plugin as VitePlugin, ViteDevServer } from 'vite';
 import { normalizePath } from 'vite';
 import type { AstroLogger } from '../core/logger/core.js';
 import { runHookServerSetup } from '../integrations/hooks.js';
@@ -14,29 +14,45 @@ export default function astroIntegrationsContainerPlugin({
 	settings: AstroSettings;
 	logger: AstroLogger;
 }): VitePlugin {
+	let server: ViteDevServer | undefined;
 	return {
 		name: 'astro:integration-container',
-		async configureServer(server) {
-			if (server.config.isProduction) return;
-			await runHookServerSetup({ config: settings.config, server, logger });
+		async configureServer(_server) {
+			server = _server;
+			if (_server.config.isProduction) return;
+			await runHookServerSetup({ config: settings.config, server: _server, logger });
 		},
 		async buildStart() {
 			if (settings.injectedRoutes.length === settings.resolvedInjectedRoutes.length) return;
-			// Ensure the injectedRoutes are all resolved to their final paths through Rollup
 			settings.resolvedInjectedRoutes = await Promise.all(
-				settings.injectedRoutes.map((route) => resolveEntryPoint.call(this, route)),
+				settings.injectedRoutes.map((route) =>
+					resolveEntryPoint(route, server, this),
+				),
 			);
 		},
 	};
 }
 
 async function resolveEntryPoint(
-	this: PluginContext,
 	route: InternalInjectedRoute,
+	server: ViteDevServer | undefined,
+	pluginContext: PluginContext,
 ): Promise<ResolvedInjectedRoute> {
-	const resolvedId = await this.resolve(route.entrypoint.toString())
-		.then((res) => res?.id)
-		.catch(() => undefined);
+	const entrypoint = route.entrypoint.toString();
+	// In dev, resolve through the SSR environment's plugin container to avoid
+	// triggering the client dep optimizer's registerMissingImport, which can
+	// race against optimizer init and corrupt the metadata cache.
+	// In build, this.resolve() is safe since there's no dep optimizer race.
+	let resolvedId: string | undefined;
+	if (server) {
+		const resolved = await server.environments.ssr.pluginContainer.resolveId(entrypoint);
+		resolvedId = resolved?.id;
+	} else {
+		resolvedId = await pluginContext
+			.resolve(entrypoint)
+			.then((res) => res?.id)
+			.catch(() => undefined);
+	}
 	if (!resolvedId) return route;
 
 	const resolvedEntryPoint = new URL(`file://${normalizePath(resolvedId)}`);