From 67f52c24b0bc477d13dcb6bd13750e655574ea96 Mon Sep 17 00:00:00 2001
From: Adam Chalemian <adam@chal.net>
Date: Mon, 4 May 2026 10:07:55 -0400
Subject: [PATCH] fix(sync): skip adapter configureServer hooks during type
 generation
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The temp Vite server created by `astro build` for type generation only
resolves virtual modules — it never serves HTTP requests. Adapter
plugins (notably `@cloudflare/vite-plugin` via `@astrojs/cloudflare`)
were still firing `configureServer` and starting heavy runtimes
(miniflare/workerd), and Vite 7's per-environment config meant
`optimizeDeps.noDiscovery` only applied to the `client` environment so
adapters were re-injecting large `optimizeDeps.include` lists into
server environments.

Two changes in `createTempViteServer`:

1. Set `optimizeDeps: { noDiscovery: true, include: [] }` on every
   environment (`client`, `ssr`, `astro`, `prerender`).
2. Add an inline `astro:sync:strip-server-hooks` plugin that removes
   `configureServer` from non-Astro plugins in `configResolved`.
   Astro's own plugins are preserved.

On a representative project this drops the “Types Generated” phase
from ~3.6 s to ~125 ms.

Closes #16332
---
 .changeset/fast-sync-temp-server.md   |  5 +++++
 packages/astro/src/core/sync/index.ts | 32 +++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 .changeset/fast-sync-temp-server.md

diff --git a/.changeset/fast-sync-temp-server.md b/.changeset/fast-sync-temp-server.md
new file mode 100644
index 000000000000..bd170c55b6c7
--- /dev/null
+++ b/.changeset/fast-sync-temp-server.md
@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Skips adapter `configureServer` hooks and per-environment dependency pre-bundling during the temporary Vite server used by `astro build` for type generation. The temp server only resolves virtual modules — it never serves HTTP requests — so starting adapter runtimes (e.g. miniflare/workerd via `@astrojs/cloudflare`) and pre-bundling adapter `optimizeDeps.include` lists were both unnecessary. On a representative project this reduces the “Types Generated” phase from ~3.6 s to ~125 ms.
diff --git a/packages/astro/src/core/sync/index.ts b/packages/astro/src/core/sync/index.ts
index bf04261585f1..bcec400b72d3 100644
--- a/packages/astro/src/core/sync/index.ts
+++ b/packages/astro/src/core/sync/index.ts
@@ -234,6 +234,12 @@ async function createTempViteServer(
 		{ dev: true },
 	);
 
+	// Disable dependency optimization for all environments. The temp server only needs
+	// to resolve virtual modules for type generation, not pre-bundle dependencies.
+	// Setting this per-environment ensures adapter plugins (e.g. Cloudflare) see the
+	// flag and skip injecting their own optimizeDeps.include lists.
+	const noOptimize = { optimizeDeps: { noDiscovery: true, include: [] } };
+
 	const tempViteServer = await createServer(
 		await createVite(
 			{
@@ -241,6 +247,32 @@ async function createTempViteServer(
 				optimizeDeps: { noDiscovery: true },
 				ssr: { external: [] },
 				logLevel: 'silent',
+				environments: {
+					client: noOptimize,
+					ssr: noOptimize,
+					astro: noOptimize,
+					prerender: noOptimize,
+				},
+				plugins: [
+					// Strip `configureServer` hooks from non-Astro plugins. The temp
+					// server is only used to resolve modules for type generation — it
+					// never serves HTTP requests. Removing these hooks prevents adapter
+					// plugins from starting heavy runtimes (e.g. miniflare/workerd for
+					// Cloudflare). Astro's own plugins (prefixed with `astro:`) are
+					// preserved because some rely on configureServer to set up state
+					// needed by their other hooks.
+					{
+						name: 'astro:sync:strip-server-hooks',
+						enforce: 'pre',
+						configResolved(config) {
+							for (const plugin of config.plugins) {
+								if (plugin.configureServer && !plugin.name.startsWith('astro:')) {
+									delete plugin.configureServer;
+								}
+							}
+						},
+					},
+				],
 			},
 			{
 				routesList,