From 074b828717cef2e02d5a098957018a802cae72e2 Mon Sep 17 00:00:00 2001
From: Justineo <justice360@gmail.com>
Date: Fri, 29 May 2020 18:55:10 +0800
Subject: [PATCH] fix(#3294): use loadFileSync when loading plugins with
 syncImport: true

---
 lib/less-node/plugin-loader.js |  8 ++++++++
 lib/less/import-manager.js     | 36 ++++++++++++++++++++++++----------
 2 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/lib/less-node/plugin-loader.js b/lib/less-node/plugin-loader.js
index 8bdcb42ef..e55218192 100644
--- a/lib/less-node/plugin-loader.js
+++ b/lib/less-node/plugin-loader.js
@@ -30,6 +30,10 @@ class PluginLoader extends AbstractPluginLoader {
             context.prefixes = ['less-plugin-', ''];
         }
 
+        if (context.syncImport) {
+            return fileManager.loadFileSync(filename, basePath, context, environment);
+        }
+
         return new Promise((fulfill, reject) => {
             fileManager.loadFile(filename, basePath, context, environment).then(
                 data => {
@@ -45,7 +49,11 @@ class PluginLoader extends AbstractPluginLoader {
                 reject(err);
             });
         });
+    }
 
+    loadPluginSync(filename, basePath, context, environment, fileManager) {
+        context.syncImport = true;
+        return this.loadPlugin(filename, basePath, context, environment, fileManager);
     }
 }
 
diff --git a/lib/less/import-manager.js b/lib/less/import-manager.js
index 471484505..d811d04a5 100644
--- a/lib/less/import-manager.js
+++ b/lib/less/import-manager.js
@@ -138,6 +138,7 @@ export default environment => {
                     }
                 }
             };
+            let loadedFile;
             let promise;
             const context = utils.clone(this.context);
 
@@ -147,19 +148,34 @@ export default environment => {
 
             if (importOptions.isPlugin) {
                 context.mime = 'application/javascript';
-                promise = pluginLoader.loadPlugin(path, currentFileInfo.currentDirectory, context, environment, fileManager);
+
+                if (context.syncImport) {
+                    loadedFile = pluginLoader.loadPluginSync(path, currentFileInfo.currentDirectory, context, environment, fileManager);
+                } else {
+                    promise = pluginLoader.loadPlugin(path, currentFileInfo.currentDirectory, context, environment, fileManager);
+                }
             }
             else {
-                promise = fileManager.loadFile(path, currentFileInfo.currentDirectory, context, environment,
-                    (err, loadedFile) => {
-                        if (err) {
-                            fileParsedFunc(err);
-                        } else {
-                            loadFileCallback(loadedFile);
-                        }
-                    });
+                if (context.syncImport) {
+                    loadedFile = fileManager.loadFileSync(path, currentFileInfo.currentDirectory, context, environment);
+                } else {
+                    promise = fileManager.loadFile(path, currentFileInfo.currentDirectory, context, environment,
+                        (err, loadedFile) => {
+                            if (err) {
+                                fileParsedFunc(err);
+                            } else {
+                                loadFileCallback(loadedFile);
+                            }
+                        });
+                }
             }
-            if (promise) {
+            if (loadedFile) {
+                if (!loadedFile.filename) {
+                    fileParsedFunc(loadedFile);
+                } else {
+                    loadFileCallback(loadedFile);
+                }
+            } else if (promise) {
                 promise.then(loadFileCallback, fileParsedFunc);
             }
         }