Add secret command-line option to print all help text

Suppress the help text for this option.

In order to find all subcommands, the code needs to introspect on the
parser, which is most easily achieved within stratis-cli source.

Canonicalize the order of the help text output alphabetically by
subparser name.

Add a test for the --print-all-help option and remove the old test because
it duplicates the --print-all-help option action.

Suppress the output from the help text unit test. It's fairly verbose and
after this PR the output will be available from the stratis-cli
command-line, so there will be almost no utility in having it stored in
every test run also.

Signed-off-by: mulhern <[email protected]>

src/stratis_cli/_parser/_parser.py

@@ -33,6 +33,7 @@
 from ._logical import LOGICAL_SUBCMDS
 from ._physical import PHYSICAL_SUBCMDS
 from ._pool import POOL_SUBCMDS
+from ._range import PrintHelpAction
 
 
 def print_help(parser):
@@ -213,6 +214,11 @@ def gen_parser():
     # version is special, it has explicit support in argparse
     parser.add_argument("--version", action="version", version=__version__)
 
+    # --print-all-help is special because it introspects on the parser
+    parser.add_argument(
+        "--print-all-help", action=PrintHelpAction, help=argparse.SUPPRESS, nargs=0
+    )
+
     _add_args(parser, GEN_ARGS)
 
     subparsers = parser.add_subparsers(title="subcommands")

src/stratis_cli/_parser/_range.py

@@ -18,6 +18,7 @@
 # isort: STDLIB
 import argparse
 import re
+import sys
 
 # isort: THIRDPARTY
 from justbytes import B, GiB, KiB, MiB, PiB, Range, TiB
@@ -98,3 +99,35 @@ class DefaultAction(argparse.Action):
     def __call__(self, parser, namespace, values, option_string=None):
         setattr(namespace, self.dest, values)
         setattr(namespace, self.dest + "_default", False)
+
+
+def gen_subparsers(parser, command_line):
+    """
+    Yield all subparser/command_lines pairs for this parser and this prefix
+    command line.
+
+    :param parser: an argparse parser
+    :param command_line: a prefix command line
+    :type command_line: list of str
+    """
+    yield (parser, command_line)
+    for action in (
+        action
+        for action in parser._actions  # pylint: disable=protected-access
+        if isinstance(
+            action, argparse._SubParsersAction  # pylint: disable=protected-access
+        )
+    ):
+        for name, subparser in sorted(action.choices.items(), key=lambda x: x[0]):
+            yield from gen_subparsers(subparser, command_line + [name])
+
+
+class PrintHelpAction(argparse.Action):
+    """
+    Print the help text for every subcommand.
+    """
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        for subparser, _ in gen_subparsers(parser, []):
+            subparser.print_help()
+        sys.exit(0)

tests/whitebox/integration/test_parser.py

@@ -15,6 +15,10 @@
 Test command-line argument parsing.
 """
 
+# isort: STDLIB
+from io import StringIO
+from unittest import mock
+
 # isort: LOCAL
 from stratis_cli import StratisCliErrorCodes
 
@@ -432,3 +436,16 @@ def test_stratis_list_default(self):
         for subcommand in [["pool"], ["filesystem"], ["blockdev"]]:
             for prefix in [[], ["--propagate"]]:
                 self.assertEqual(RUNNER(prefix + subcommand), 0)
+
+
+class TestAllHelp(RunTestCase):
+    """
+    Verify that --print-all-help option succeeds.
+    """
+
+    def test_print_all_help(self):
+        """
+        Test the --print-all-help option.
+        """
+        with mock.patch("sys.stdout", new=StringIO()):
+            self.check_system_exit(["--print-all-help"], 0)