[build, devscripts] Add devscript to set a build variant

Closes #4471

devscripts/make_readme.py

@@ -45,6 +45,10 @@ switch_col_width = len(re.search(r'(?m)^\s{5,}', options).group())
 delim = f'\n{" " * switch_col_width}'
 
 PATCHES = (
+    (   # Standardize update message
+        r'(?m)^(    -U, --update\s+).+(\n    \s.+)*$',
+        r'\1Update this program to the latest version',
+    ),
     (  # Headings
         r'(?m)^  (\w.+\n)(    (?=\w))?',
         r'## \1'

devscripts/set-variant.py

@@ -0,0 +1,36 @@
+#!/usr/bin/env python3
+
+# Allow direct execution
+import os
+import sys
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+
+import argparse
+import functools
+import re
+
+from devscripts.utils import compose_functions, read_file, write_file
+
+VERSION_FILE = 'yt_dlp/version.py'
+
+
+def parse_options():
+    parser = argparse.ArgumentParser(description='Set the build variant of the package')
+    parser.add_argument('variant', help='Name of the variant')
+    parser.add_argument('-M', '--update-message', default=None, help='Message to show in -U')
+    return parser.parse_args()
+
+
+def property_setter(name, value):
+    return functools.partial(re.sub, rf'(?m)^{name}\s*=\s*.+$', f'{name} = {value!r}')
+
+
+opts = parse_options()
+transform = compose_functions(
+    property_setter('VARIANT', opts.variant),
+    property_setter('UPDATE_HINT', opts.update_message)
+)
+
+write_file(VERSION_FILE, transform(read_file(VERSION_FILE)))

devscripts/update-version.py

@@ -43,6 +43,10 @@ VERSION_FILE = f'''\
 __version__ = {VERSION!r}
 
 RELEASE_GIT_HEAD = {GIT_HEAD!r}
+
+VARIANT = None
+
+UPDATE_HINT = None
 '''
 
 write_file('yt_dlp/version.py', VERSION_FILE)