Python: add messaging about deprecated options

python/extractor/semmle/cmdline.py

@@ -102,6 +102,8 @@ def make_parser():
     config_options.add_option("--colorize", dest="colorize", default=False, action="store_true",
                       help = """Colorize the logging output.""")
 
+    config_options.add_option("--dont-extract-stdlib", dest="extract_stdlib", action="store_false",
+        help="This flag is deprecated; not extracting the standard library is now the default.")
     config_options.add_option("--extract-stdlib", dest="extract_stdlib", default=False, action="store_true",
         help="Extract the standard library.")
 
@@ -224,10 +226,18 @@ def parse(command_line):
         max_import_depth = float('inf')
     options.max_import_depth = max_import_depth
 
+    if 'CODEQL_EXTRACTOR_PYTHON_DONT_EXTRACT_STDLIB' in os.environ:
+        options.extract_stdlib = False
+        print ("Warning: CODEQL_EXTRACTOR_PYTHON_DONT_EXTRACT_STDLIB is deprecated; the default is now to not extract the standard library.")
+
     if 'CODEQL_EXTRACTOR_PYTHON_EXTRACT_STDLIB' in os.environ:
         options.extract_stdlib = True
 
     options.prune = True
+
+    if option.extract_stdlib:
+        print ("Warning: The analysis will extract the standard library. This behavior is deprecated and will be removed in a future release. We expect it to be gone in CLI version 2.20.0.")
+
     return options, args
 
 def split_and_flatten(options_list, div):