cmdline: --conf -> --confdir, which specifies the config directory, not the yaml options file

This is a much more sensible behaviour for the flag.

CHANGELOG

@@ -9,6 +9,8 @@
     * Configure mitmproxy console keybindings with the keys.yaml file. See docs for more.
 
   ** Breaking Changes **
+    * The --conf command-line flag is now --confdir, and specifies the mitmproxy configuration
+    directory, instead of the options yaml file (which is at `config.yaml` under the configuration directory).
     * `allow_remote` got replaced by `block_global` and `block_private` (#3100)
     * No more custom events (#3093)
     * The `cadir` option has been renamed to `confdir`

mitmproxy/tools/cmdline.py

@@ -1,12 +1,8 @@
 import argparse
-import os
 
 from mitmproxy.addons import core
 
 
-CONFIG_PATH = os.path.join(core.CONF_DIR, "config.yaml")
-
-
 def common_options(parser, opts):
     parser.add_argument(
         '--version',
@@ -25,10 +21,10 @@ def common_options(parser, opts):
         help="Show all commands and their signatures",
     )
     parser.add_argument(
-        "--conf",
-        type=str, dest="conf", default=CONFIG_PATH,
+        "--confdir",
+        type=str, dest="confdir", default=core.CONF_DIR,
         metavar="PATH",
-        help="Read options from a configuration file"
+        help="Path to the mitmproxy config directory"
     )
     parser.add_argument(
         "--set",

mitmproxy/tools/main.py

@@ -23,6 +23,8 @@ from mitmproxy import proxy  # noqa
 from mitmproxy import log  # noqa
 from mitmproxy.utils import debug, arg_check  # noqa
 
+OPTIONS_FILE_NAME = "config.yaml"
+
 
 def assert_utf8_env():
     spec = ""
@@ -90,7 +92,11 @@ def run(
         arg_check.check()
         sys.exit(1)
     try:
-        unknown = optmanager.load_paths(opts, args.conf)
+        opts.confdir = args.confdir
+        unknown = optmanager.load_paths(
+            opts,
+            os.path.join(opts.confdir, OPTIONS_FILE_NAME),
+        )
         pconf = process_options(parser, opts, args)
         server: typing.Any = None
         if pconf.options.server: