From dc7c2683dae15c2c12619255ae983659fad477ef Mon Sep 17 00:00:00 2001
From: Megrax <geronimooo@foxmail.com>
Date: Tue, 4 Oct 2022 00:22:02 +0800
Subject: [PATCH] fix: add a warning if css urls not exist during build time
 (fix #9800)

---
 packages/vite/src/node/plugins/css.ts | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/packages/vite/src/node/plugins/css.ts b/packages/vite/src/node/plugins/css.ts
index 824dc8d571c91e..3403b854d16a62 100644
--- a/packages/vite/src/node/plugins/css.ts
+++ b/packages/vite/src/node/plugins/css.ts
@@ -217,6 +217,12 @@ export function cssPlugin(config: ResolvedConfig): Plugin {
         if (resolved) {
           return fileToUrl(resolved, config, this)
         }
+        if (config.command === 'build') {
+          // #9800 If we cannot resolve the css url, leave a warning.
+          config.logger.warnOnce(
+            `\n${url} doesn't exist at build time, it will remain unchanged to be resolved at runtime`
+          )
+        }
         return url
       }