[update] Implement --update-to repo

Authored by: Grub4K, pukkandan

yt_dlp/__init__.py

@@ -939,7 +939,7 @@ def _real_main(argv=None):
             ydl.cache.remove()
 
         try:
-            updater = Updater(ydl, opts.update_self if isinstance(opts.update_self, str) else None)
+            updater = Updater(ydl, opts.update_self)
             if opts.update_self and updater.update() and actual_use:
                 if updater.cmd:
                     return updater.restart()

yt_dlp/options.py

@@ -323,7 +323,7 @@ def create_parser():
         help='Print program version and exit')
     general.add_option(
         '-U', '--update',
-        action='store_true', dest='update_self',
+        action='store_const', dest='update_self', const=CHANNEL,
         help=format_field(
             is_non_updateable(), None, 'Check if updates are available. %s',
             default=f'Update this program to the latest {CHANNEL} version'))
@@ -335,9 +335,9 @@ def create_parser():
         '--update-to',
         action='store', dest='update_self', metavar='[CHANNEL]@[TAG]',
         help=(
-            'Upgrade/downgrade to a specific version. CHANNEL and TAG defaults to '
-            f'"{CHANNEL}" and "latest" respectively if omitted; See "UPDATE" for details. '
-            f'Supported channels: {", ".join(UPDATE_SOURCES)}'))
+            'Upgrade/downgrade to a specific version. CHANNEL can be a repository as well. '
+            f'CHANNEL and TAG default to "{CHANNEL.partition("@")[0]}" and "latest" respectively if omitted; '
+            f'See "UPDATE" for details. Supported channels: {", ".join(UPDATE_SOURCES)}'))
     general.add_option(
         '-i', '--ignore-errors',
         action='store_true', dest='ignoreerrors',

yt_dlp/update.py

@@ -129,27 +129,36 @@ class Updater:
         self.ydl = ydl
 
         self.target_channel, sep, self.target_tag = (target or CHANNEL).rpartition('@')
-        if not sep and self.target_tag in UPDATE_SOURCES:  # stable => stable@latest
-            self.target_channel, self.target_tag = self.target_tag, None
+        # stable => stable@latest
+        if not sep and ('/' in self.target_tag or self.target_tag in UPDATE_SOURCES):
+            self.target_channel = self.target_tag
+            self.target_tag = None
         elif not self.target_channel:
-            self.target_channel = CHANNEL
+            self.target_channel = CHANNEL.partition('@')[0]
 
         if not self.target_tag:
-            self.target_tag, self._exact = 'latest', False
+            self.target_tag = 'latest'
+            self._exact = False
         elif self.target_tag != 'latest':
             self.target_tag = f'tags/{self.target_tag}'
 
-    @property
-    def _target_repo(self):
-        try:
-            return UPDATE_SOURCES[self.target_channel]
-        except KeyError:
-            return self._report_error(
-                f'Invalid update channel {self.target_channel!r} requested. '
-                f'Valid channels are {", ".join(UPDATE_SOURCES)}', True)
+        if '/' in self.target_channel:
+            self._target_repo = self.target_channel
+            if self.target_channel not in (CHANNEL, *UPDATE_SOURCES.values()):
+                self.ydl.report_warning(
+                    f'You are switching to an {self.ydl._format_err("unofficial", "red")} executable '
+                    f'from {self.ydl._format_err(self._target_repo, self.ydl.Styles.EMPHASIS)}. '
+                    f'Run {self.ydl._format_err("at your own risk", "light red")}')
+                self.restart = self._blocked_restart
+        else:
+            self._target_repo = UPDATE_SOURCES.get(self.target_channel)
+            if not self._target_repo:
+                self._report_error(
+                    f'Invalid update channel {self.target_channel!r} requested. '
+                    f'Valid channels are {", ".join(UPDATE_SOURCES)}', True)
 
     def _version_compare(self, a, b, channel=CHANNEL):
-        if channel != self.target_channel:
+        if self._exact and channel != self.target_channel:
             return False
 
         if _VERSION_RE.fullmatch(f'{a}.{b}'):
@@ -372,6 +381,12 @@ class Updater:
         _, _, returncode = Popen.run(self.cmd)
         return returncode
 
+    def _blocked_restart(self):
+        self._report_error(
+            'Automatically restarting into custom builds is disabled for security reasons. '
+            'Restart yt-dlp to use the updated version', expected=True)
+        return self.ydl._download_retcode
+
 
 def run_update(ydl):
     """Update the program file with the latest version from the repository