[extractor] Import `_ALL_CLASSES` lazily

This significantly speeds up `import yt_dlp` in the absence of `lazy_extractors`

1 files changed, 4 insertions, 2 deletions

diff --git a/yt_dlp/YoutubeDL.py b/yt_dlp/YoutubeDL.py
index 7ba6441e1..1932af3fe 100644
--- a/yt_dlp/YoutubeDL.py
+++ b/yt_dlp/YoutubeDL.py
@@ -38,8 +38,6 @@ from .compat import (
 from .cookies import load_cookies
 from .downloader import FFmpegFD, get_suitable_downloader, shorten_protocol_name
 from .downloader.rtmp import rtmpdump_version
-from .extractor import _LAZY_LOADER
-from .extractor import _PLUGIN_CLASSES as plugin_extractors
 from .extractor import gen_extractor_classes, get_info_extractor
 from .extractor.openload import PhantomJSwrapper
 from .minicurses import format_text
@@ -3659,6 +3657,10 @@ class YoutubeDL:
         if not self.params.get('verbose'):
             return
 
+        # These imports can be slow. So import them only as needed
+        from .extractor.extractors import _LAZY_LOADER
+        from .extractor.extractors import _PLUGIN_CLASSES as plugin_extractors
+
         def get_encoding(stream):
             ret = str(getattr(stream, 'encoding', 'missing (%s)' % type(stream).__name__))
             if not supports_terminal_sequences(stream):