Determine whether to add a subparser to completion by its presence in _get_subactions()

This is the logic argparse uses for showing a subparser in the list of
options, so shtab now matches that behavior. This is particularly important
for subparsers which pass `add_help=False` in order to provide their *own*
help implementation.

Author: jimporter

shtab/__init__.py

@@ -141,6 +141,16 @@ def wordify(string):
     return string.replace("-", "_").replace(".", " ").replace(" ", "_")
 
 
+def get_public_subcommands(sub):
+    """Get all the publicly-visible subcommands for a given subparser."""
+    # NOTE: public subcommands have their primary name listed in the result of
+    # `_get_subactions()`. We use this to get the parser for each subcommand and
+    # compare all the choices (including aliases!) to the set of known-public
+    # parsers.
+    public_parsers = {id(sub.choices[i.dest]) for i in sub._get_subactions()}
+    return {k for k, v in sub.choices.items() if id(v) in public_parsers}
+
+
 def get_bash_commands(root_parser, root_prefix, choice_functions=None):
     """
     Recursive subcommand parser traversal, returning lists of information on
@@ -204,6 +214,9 @@ def recurse(parser, prefix):
                 # choices (including subparsers & shtab `.complete` functions)
                 log.debug("choices:{}:{}".format(prefix, sorted(positional.choices)))
 
+                if isinstance(positional.choices, dict):
+                    public_cmds = get_public_subcommands(positional)
+
                 this_positional_choices = []
                 for choice in positional.choices:
                     if isinstance(choice, Choice):
@@ -222,7 +235,7 @@ def recurse(parser, prefix):
                     elif isinstance(positional.choices, dict):
                         # subparser, so append to list of subparsers & recurse
                         log.debug("subcommand:%s", choice)
-                        if positional.choices[choice].add_help:
+                        if choice in public_cmds:
                             discovered_subparsers.append(str(choice))
                             this_positional_choices.append(str(choice))
                             (
@@ -577,8 +590,9 @@ def format_positional(opt):
                 root_arguments.append(format_positional(opt))
         else:  # subparser
             log.debug("choices:{}:{}".format(root_prefix, sorted(sub.choices)))
+            public_cmds = get_public_subcommands(sub)
             for cmd, subparser in sub.choices.items():
-                if not subparser.add_help:
+                if cmd not in public_cmds:
                     log.debug("skip:subcommand:%s", cmd)
                     continue
                 log.debug("subcommand:%s", cmd)

tests/test_shtab.py

@@ -177,7 +177,7 @@ def test_custom_complete(shell, caplog):
 def test_subparser_custom_complete(shell, caplog):
     parser = ArgumentParser(prog="test")
     subparsers = parser.add_subparsers()
-    sub = subparsers.add_parser("sub")
+    sub = subparsers.add_parser("sub", help="help message")
     sub.add_argument("posA").complete = {"bash": "_shtab_test_some_func"}
     preamble = {"bash": "_shtab_test_some_func() { compgen -W 'one two' -- $1 ;}"}
     with caplog.at_level(logging.INFO):
@@ -194,6 +194,31 @@ def test_subparser_custom_complete(shell, caplog):
     assert not caplog.record_tuples
 
 
+@fix_shell
+def test_subparser_aliases(shell, caplog):
+    parser = ArgumentParser(prog="test")
+    subparsers = parser.add_subparsers()
+    sub = subparsers.add_parser("sub", aliases=["xsub", "ysub"], help="help message")
+    sub.add_argument("posA").complete = {"bash": "_shtab_test_some_func"}
+    preamble = {"bash": "_shtab_test_some_func() { compgen -W 'one two' -- $1 ;}"}
+    with caplog.at_level(logging.INFO):
+        completion = shtab.complete(parser, shell=shell, preamble=preamble)
+    print(completion)
+
+    if shell == "bash":
+        shell = Bash(completion)
+        shell.compgen('-W "${_shtab_test_subparsers[*]}"', "s", "sub")
+        shell.compgen('-W "$_shtab_test_pos_0_choices"', "s", "sub")
+        shell.compgen('-W "${_shtab_test_subparsers[*]}"', "x", "xsub")
+        shell.compgen('-W "$_shtab_test_pos_0_choices"', "x", "xsub")
+        shell.compgen('-W "${_shtab_test_subparsers[*]}"', "y", "ysub")
+        shell.compgen('-W "$_shtab_test_pos_0_choices"', "y", "ysub")
+        shell.test('"$($_shtab_test_sub_pos_0_COMPGEN o)" = "one"')
+        shell.test('-z "$_shtab_test_COMPGEN"')
+
+    assert not caplog.record_tuples
+
+
 @fix_shell
 def test_add_argument_to_optional(shell, caplog):
     parser = ArgumentParser(prog="test")
@@ -213,7 +238,7 @@ def test_add_argument_to_optional(shell, caplog):
 def test_add_argument_to_positional(shell, caplog, capsys):
     parser = ArgumentParser(prog="test")
     subparsers = parser.add_subparsers()
-    sub = subparsers.add_parser("completion")
+    sub = subparsers.add_parser("completion", help="help message")
     shtab.add_argument_to(sub, "shell", parent=parser)
     from argparse import Namespace