Refactor argument parser construction

Each subparser is added in its own function

pipx/main.py

@@ -2,7 +2,6 @@
 # PYTHON_ARGCOMPLETE_OK
 
 """The command line interface to pipx"""
-
 import argcomplete  # type: ignore
 import argparse
 import functools
@@ -30,6 +29,7 @@
 
 
 __version__ = "0.14.0.0"
+__version_info__ = tuple(int(n) for n in __version__.split("."))
 
 
 def print_version() -> None:
@@ -266,21 +266,7 @@ def _autocomplete_list_of_installed_packages(
     return list(str(p.name) for p in sorted(venv_container.iter_venv_dirs()))
 
 
-def get_command_parser():
-    venv_container = VenvContainer(PIPX_LOCAL_VENVS)
-
-    autocomplete_list_of_installed_packages = functools.partial(
-        _autocomplete_list_of_installed_packages, venv_container
-    )
-
-    parser = argparse.ArgumentParser(
-        formatter_class=LineWrapRawTextHelpFormatter, description=PIPX_DESCRIPTION
-    )
-
-    subparsers = parser.add_subparsers(
-        dest="command", description="Get help for commands with pipx COMMAND --help"
-    )
-
+def _add_install(subparsers):
     p = subparsers.add_parser(
         "install",
         help="Install a package",
@@ -307,6 +293,8 @@ def get_command_parser():
     )
     add_pip_venv_args(p)
 
+
+def _add_inject(subparsers, autocomplete_list_of_installed_packages):
     p = subparsers.add_parser(
         "inject",
         help="Install packages into an existing Virtual Environment",
@@ -336,6 +324,8 @@ def get_command_parser():
     )
     p.add_argument("--verbose", action="store_true")
 
+
+def _add_upgrade(subparsers, autocomplete_list_of_installed_packages):
     p = subparsers.add_parser(
         "upgrade",
         help="Upgrade a package",
@@ -353,6 +343,8 @@ def get_command_parser():
     add_pip_venv_args(p)
     p.add_argument("--verbose", action="store_true")
 
+
+def _add_upgrade_all(subparsers):
     p = subparsers.add_parser(
         "upgrade-all",
         help="Upgrade all packages. "
@@ -371,6 +363,8 @@ def get_command_parser():
     )
     p.add_argument("--verbose", action="store_true")
 
+
+def _add_uninstall(subparsers, autocomplete_list_of_installed_packages):
     p = subparsers.add_parser(
         "uninstall",
         help="Uninstall a package",
@@ -379,13 +373,17 @@ def get_command_parser():
     p.add_argument("package").completer = autocomplete_list_of_installed_packages
     p.add_argument("--verbose", action="store_true")
 
+
+def _add_uninstall_all(subparsers):
     p = subparsers.add_parser(
         "uninstall-all",
         help="Uninstall all packages",
         description="Uninstall all pipx-managed packages",
     )
     p.add_argument("--verbose", action="store_true")
 
+
+def _add_reinstall_all(subparsers):
     p = subparsers.add_parser(
         "reinstall-all",
         formatter_class=LineWrapRawTextHelpFormatter,
@@ -410,13 +408,17 @@ def get_command_parser():
     p.add_argument("--skip", nargs="+", default=[], help="skip these packages")
     p.add_argument("--verbose", action="store_true")
 
+
+def _add_list(subparsers):
     p = subparsers.add_parser(
         "list",
         help="List installed packages",
         description="List packages and apps installed with pipx",
     )
     p.add_argument("--verbose", action="store_true")
 
+
+def _add_run(subparsers):
     p = subparsers.add_parser(
         "run",
         formatter_class=LineWrapRawTextHelpFormatter,
@@ -427,17 +429,17 @@ def get_command_parser():
         ),
         description=textwrap.dedent(
             f"""
-        Download the latest version of a package to a temporary virtual environment,
-        then run an app from it. The environment will be cached
-        and re-used for up to {TEMP_VENV_EXPIRATION_THRESHOLD_DAYS} days. This
-        means subsequent calls to 'run' for the same package will be faster
-        since they can re-use the cached Virtual Environment.
-
-        In support of PEP 582 'run' will use apps found in a local __pypackages__
-         directory, if present. Please note that this behavior is experimental,
-         and is a acts as a companion tool to pythonloc. It may be modified or
-         removed in the future. See https://github.com/cs01/pythonloc.
-        """
+            Download the latest version of a package to a temporary virtual environment,
+            then run an app from it. The environment will be cached
+            and re-used for up to {TEMP_VENV_EXPIRATION_THRESHOLD_DAYS} days. This
+            means subsequent calls to 'run' for the same package will be faster
+            since they can re-use the cached Virtual Environment.
+
+            In support of PEP 582 'run' will use apps found in a local __pypackages__
+             directory, if present. Please note that this behavior is experimental,
+             and is a acts as a companion tool to pythonloc. It may be modified or
+             removed in the future. See https://github.com/cs01/pythonloc.
+            """
         ),
     )
     p.add_argument(
@@ -466,6 +468,8 @@ def get_command_parser():
     )
     add_pip_venv_args(p)
 
+
+def _add_runpip(subparsers, autocomplete_list_of_installed_packages):
     p = subparsers.add_parser(
         "runpip",
         help="Run pip in an existing pipx-managed Virtual Environment",
@@ -483,6 +487,8 @@ def get_command_parser():
     )
     p.add_argument("--verbose", action="store_true")
 
+
+def _add_ensurepath(subparsers):
     p = subparsers.add_parser(
         "ensurepath",
         help=(
@@ -500,10 +506,38 @@ def get_command_parser():
             f"PATH already has {str(LOCAL_BIN_DIR)}"
         ),
     )
+
+
+def get_command_parser():
+    venv_container = VenvContainer(PIPX_LOCAL_VENVS)
+
+    autocomplete_list_of_installed_packages = functools.partial(
+        _autocomplete_list_of_installed_packages, venv_container
+    )
+
+    parser = argparse.ArgumentParser(
+        formatter_class=LineWrapRawTextHelpFormatter, description=PIPX_DESCRIPTION
+    )
+
+    subparsers = parser.add_subparsers(
+        dest="command", description="Get help for commands with pipx COMMAND --help"
+    )
+
+    _add_install(subparsers)
+    _add_inject(subparsers, autocomplete_list_of_installed_packages)
+    _add_upgrade(subparsers, autocomplete_list_of_installed_packages)
+    _add_upgrade_all(subparsers)
+    _add_uninstall(subparsers, autocomplete_list_of_installed_packages)
+    _add_uninstall_all(subparsers)
+    _add_reinstall_all(subparsers)
+    _add_list(subparsers)
+    _add_run(subparsers)
+    _add_runpip(subparsers, autocomplete_list_of_installed_packages)
+    _add_ensurepath(subparsers)
+
     parser.add_argument("--version", action="store_true", help="Print version and exit")
-    p = subparsers.add_parser(
-        "completions",
-        help=("Print instructions on enabling shell completions for pipx"),
+    subparsers.add_parser(
+        "completions", help="Print instructions on enabling shell completions for pipx"
     )
     return parser