Fix #3741 — symlink support in new plugin manager

CHANGES.txt

@@ -7,6 +7,7 @@ Features
 Bugfixes
 --------
 
+* Fix the new plugin manager not loading plugins if the plugin folder is a symlink (Issue #3741)
 * Fix the ``nikola plugin`` command not working (Issue #3736)
 
 New in v8.3.0

nikola/plugin_manager.py

@@ -31,6 +31,8 @@
 import importlib.util
 import time
 import sys
+
+from collections import deque
 from dataclasses import dataclass
 from pathlib import Path
 from typing import Dict, List, Optional, Type, TYPE_CHECKING, Set
@@ -102,9 +104,15 @@ def locate_plugins(self) -> List[PluginCandidate]:
         """Locate plugins in plugin_places."""
         self.candidates = []
 
+        plugin_folders: deque = deque([place for place in self.plugin_places if place.exists() and place.is_dir()])
         plugin_files: List[Path] = []
-        for place in self.plugin_places:
-            plugin_files += place.rglob("*.plugin")
+        while plugin_folders:
+            base_folder = plugin_folders.popleft()
+            for item in base_folder.iterdir():
+                if item.is_dir():
+                    plugin_folders.append(item)
+                elif item.suffix == ".plugin":
+                    plugin_files.append(item)
 
         for plugin_file in plugin_files:
             source_dir = plugin_file.parent