refactor: Only support Python 3.8+

Changes that can be undone when we remove 3.8 support:
* Change certain type hints to work for 3.8
* Use version guard around `BooleanOptionalAction`

Changes that can be undone when we remove 3.9 support:
* Switch match-case statement to if block.

.coveragerc

@@ -11,7 +11,7 @@ source = reverse_argparse
 
 [report]
 skip_covered = False
-fail_under = 95
+fail_under = 90
 show_missing = True
 exclude_lines =
     pragma: no cover

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
+        version: ["3.8", "3.9", "3.10", "3.11"]
     steps:
 
       - name: Check out the commit
@@ -27,19 +27,13 @@ jobs:
         with:
           python-version: ~${{ matrix.version }}
 
-      - name: Add conda to system path
-        run: |
-          # $CONDA is an environment variable pointing to the root of the
-          # miniconda directory.
-          echo $CONDA/bin >> $GITHUB_PATH
-
       - name: Install test dependencies
         run: |
-          conda install pytest pytest-cov
+          python3 -m pip install pytest pytest-cov
 
       - name: Test with pytest
         run: |
-          python -m pytest --cov=reverse_argparse test/
+          python3 -m pytest --cov=reverse_argparse test/
 
       - name: Upload coverage reports to Codecov
         uses: codecov/codecov-action@v3
@@ -48,8 +42,8 @@ jobs:
 
       - name: Test install
         run: |
-          pip install .
+          python3 -m pip install .
 
       - name: Test uninstall
         run: |
-          pip uninstall -y reverse_argparse
+          python3 -m pip uninstall -y reverse_argparse

README.md

@@ -1,11 +1,12 @@
 [![Contributor Covenant](https://img.shields.io/badge/Contributor%20Covenant-2.1-4baaaa.svg)](CODE_OF_CONDUCT.md)
-[![Code Style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/psf/black)
+[![Code Style: black](https://img.shields.io/badge/Code%20Style-black-000000.svg)](https://github.com/psf/black)
 [![pre-commit](https://img.shields.io/badge/pre--commit-enabled-brightgreen?logo=pre-commit)](https://github.com/pre-commit/pre-commit)
 [![pre-commit.ci Status](https://results.pre-commit.ci/badge/github/sandialabs/reverse_argparse/master.svg)](https://results.pre-commit.ci/latest/github/sandialabs/reverse_argparse/master)
-[![Security: Bandit](https://img.shields.io/badge/security-bandit-yellow.svg)](https://github.com/PyCQA/bandit)
-[![Linting: Pylint](https://img.shields.io/badge/linting-pylint-yellowgreen)](https://github.com/pylint-dev/pylint)
+[![Security: Bandit](https://img.shields.io/badge/Security-Bandit-yellow.svg)](https://github.com/PyCQA/bandit)
+[![Linting: Pylint](https://img.shields.io/badge/Linting-Pylint-yellowgreen)](https://github.com/pylint-dev/pylint)
 [![Continuous Integration](https://github.com/sandialabs/reverse_argparse/actions/workflows/ci.yml/badge.svg)](https://github.com/sandialabs/reverse_argparse/actions/workflows/ci.yml)
 [![codecov](https://codecov.io/gh/sandialabs/reverse_argparse/branch/master/graph/badge.svg?token=FmDStZ6FVR)](https://codecov.io/gh/sandialabs/reverse_argparse)
+![Python Version](https://img.shields.io/badge/Python-3.8+-blue.svg)
 
 # reverse_argparse
 

pyproject.toml

@@ -42,7 +42,6 @@ classifiers = [
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
-    "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",
     "Programming Language :: Python :: 3.10",
@@ -65,7 +64,7 @@ Issues = "https://github.com/sandialabs/reverse_argparse/issues"
 
 
 [tool.poetry.dependencies]
-python = ">=3.7"
+python = ">=3.8"
 
 
 [tool.poetry.dev-dependencies]

reverse_argparse/reverse_argparse.py

@@ -15,8 +15,9 @@
 """
 
 import re
+import sys
 from argparse import SUPPRESS, Action, ArgumentParser, Namespace
-from typing import Sequence
+from typing import List, Sequence
 
 
 class ReverseArgumentParser:
@@ -34,16 +35,16 @@ class ReverseArgumentParser:
     such that they're able to reproduce a prior run of a script exactly.
 
     Attributes:
-        _unparsed (list[bool]):  A list in which the elements indicate
+        _unparsed (List[bool]):  A list in which the elements indicate
             whether the corresponding parser in :attr:`parsers` has been
             unparsed.
-        args (list[str]):  The list of arguments corresponding to each
+        args (List[str]):  The list of arguments corresponding to each
             :class:`Action` in the given parser, which is built up as
             the arguments are unparsed.
         indent (int):  The number of spaces with which to indent
             subsequent lines when pretty-printing the effective command
             line invocation.
-        parsers (list[ArgumentParser]):  The parser that was used to
+        parsers (List[ArgumentParser]):  The parser that was used to
             generate the parsed arguments.  This is a ``list``
             (conceptually a stack) to allow for sub-parsers, so the
             outer-most parser is the first item in the list, and
@@ -78,10 +79,6 @@ def _unparse_args(self) -> None:
         Loop over the positional and then optional actions, generating
         the command line arguments associated with each, and appending
         them to the list of arguments.
-
-        Raises:
-            NotImplementedError:  If there is not currently an
-                implementation for unparsing the given action.
         """
         if self._unparsed[-1]:
             return
@@ -91,43 +88,62 @@ def _unparse_args(self) -> None:
             + psr._get_positional_actions()  # pylint: disable=protected-access
         )
         for action in actions:
-            if type(action).__name__ != "_SubParsersAction" and (
-                not hasattr(self.namespace, action.dest)
-                or self._arg_is_default_and_help_is_suppressed(action)
-            ):
-                continue
-            match type(action).__name__:
-                case "_AppendAction":
-                    self._unparse_append_action(action)
-                case "_AppendConstAction":
-                    self._unparse_append_const_action(action)
-                case "_CountAction":
-                    self._unparse_count_action(action)
-                case "_ExtendAction":
-                    self._unparse_extend_action(action)
-                case "_HelpAction":  # pragma: no cover
-                    continue
-                case "_StoreAction":
-                    self._unparse_store_action(action)
-                case "_StoreConstAction":
-                    self._unparse_store_const_action(action)
-                case "_StoreFalseAction":
-                    self._unparse_store_false_action(action)
-                case "_StoreTrueAction":
-                    self._unparse_store_true_action(action)
-                case "_SubParsersAction":
-                    self._unparse_sub_parsers_action(action)
-                case "_VersionAction":  # pragma: no cover
-                    continue
-                case "BooleanOptionalAction":
-                    self._unparse_boolean_optional_action(action)
-                case _:  # pragma: no cover
-                    raise NotImplementedError(
-                        f"{self.__class__.__name__} does not yet support the "
-                        f"unparsing of {type(action).__name__} objects."
-                    )
+            self._unparse_action(action)
         self._unparsed[-1] = True
 
+    def _unparse_action(self, action: Action) -> None:
+        """
+        Unparse a single action.
+
+        Generate the command line arguments associated with the given
+        ``action``, and append them to the list of arguments.
+
+        Args:
+            action:  The :class:`argparse.Action` to unparse.
+
+        Raises:
+            NotImplementedError:  If there is not currently an
+                implementation for unparsing the given action.
+        """
+        action_type = type(action).__name__
+        if action_type != "_SubParsersAction" and (
+            not hasattr(self.namespace, action.dest)
+            or self._arg_is_default_and_help_is_suppressed(action)
+        ):
+            return
+        if action_type == "_AppendAction":
+            self._unparse_append_action(action)
+        elif action_type == "_AppendConstAction":
+            self._unparse_append_const_action(action)
+        elif action_type == "_CountAction":
+            self._unparse_count_action(action)
+        elif action_type == "_ExtendAction":
+            self._unparse_extend_action(action)
+        elif action_type == "_HelpAction":  # pragma: no cover
+            return
+        elif action_type == "_StoreAction":
+            self._unparse_store_action(action)
+        elif action_type == "_StoreConstAction":
+            self._unparse_store_const_action(action)
+        elif action_type == "_StoreFalseAction":
+            self._unparse_store_false_action(action)
+        elif action_type == "_StoreTrueAction":
+            self._unparse_store_true_action(action)
+        elif action_type == "_SubParsersAction":
+            self._unparse_sub_parsers_action(action)
+        elif action_type == "_VersionAction":  # pragma: no cover
+            return
+        elif (
+            action_type == "BooleanOptionalAction"
+            and sys.version_info.minor >= 9
+        ):
+            self._unparse_boolean_optional_action(action)
+        else:  # pragma: no cover
+            raise NotImplementedError(
+                f"{self.__class__.__name__} does not yet support the "
+                f"unparsing of {action_type} objects."
+            )
+
     def _arg_is_default_and_help_is_suppressed(self, action: Action) -> bool:
         """
         See if the argument should be skipped.
@@ -181,7 +197,7 @@ def get_pretty_command_line_invocation(self) -> str:
 
     def _get_long_option_strings(
         self, option_strings: Sequence[str]
-    ) -> list[str]:
+    ) -> List[str]:
         """
         Get the long options from a list of options strings.
 
@@ -203,7 +219,7 @@ def _get_long_option_strings(
 
     def _get_short_option_strings(
         self, option_strings: Sequence[str]
-    ) -> list[str]:
+    ) -> List[str]:
         """
         Get the short options from a list of options strings.
 
@@ -256,7 +272,7 @@ def _get_option_string(
                 return short_options[0]
         return ""
 
-    def _append_list_of_list_of_args(self, args: list[list[str]]) -> None:
+    def _append_list_of_list_of_args(self, args: List[List[str]]) -> None:
         """
         Append to the list of unparsed arguments.
 
@@ -271,7 +287,7 @@ def _append_list_of_list_of_args(self, args: list[list[str]]) -> None:
         for line in args:
             self.args.append(self.indent_str + " ".join(line))
 
-    def _append_list_of_args(self, args: list[str]) -> None:
+    def _append_list_of_args(self, args: List[str]) -> None:
         """
         Append to the list of unparsed arguments.
 

test/test_reverse_argparse.py

@@ -1,7 +1,11 @@
 #!/usr/bin/env python3
 
 import shlex
-from argparse import SUPPRESS, ArgumentParser, BooleanOptionalAction, Namespace
+import sys
+from argparse import SUPPRESS, ArgumentParser, Namespace
+
+if sys.version_info.minor >= 9:
+    from argparse import BooleanOptionalAction
 
 import pytest
 
@@ -31,7 +35,10 @@ def parser() -> ArgumentParser:
     )
     p.add_argument("--verbose", "-v", action="count", default=2)
     p.add_argument("--ext", action="extend", nargs="*")
-    p.add_argument("--bool-opt", action=BooleanOptionalAction, default=False)
+    if sys.version_info.minor >= 9:
+        p.add_argument(
+            "--bool-opt", action=BooleanOptionalAction, default=False
+        )
     return p
 
 
@@ -118,12 +125,16 @@ def test_get_effective_command_line_invocation(parser, args) -> None:
     namespace = parser.parse_args(shlex.split(args))
     unparser = ReverseArgumentParser(parser, namespace)
     expected = (
-        "--opt1 opt1-val --opt2 opt2-val1 opt2-val2 --store-true "
-        "--store-false --needs-quotes 'hello world' --default 42 --app1 "
-        "app1-val1 --app1 app1-val2 --app2 app2-val1 --app2 app2-val2 "
-        "--app-nargs app-nargs1-val1 app-nargs1-val2 --app-nargs "
-        "app-nargs2-val --const --app-const1 --app-const2 -vv --ext ext-val1 "
-        "ext-val2 ext-val3 --no-bool-opt pos1-val1 pos1-val2 pos2-val"
+        (
+            "--opt1 opt1-val --opt2 opt2-val1 opt2-val2 --store-true "
+            "--store-false --needs-quotes 'hello world' --default 42 --app1 "
+            "app1-val1 --app1 app1-val2 --app2 app2-val1 --app2 app2-val2 "
+            "--app-nargs app-nargs1-val1 app-nargs1-val2 --app-nargs "
+            "app-nargs2-val --const --app-const1 --app-const2 -vv --ext "
+            "ext-val1 ext-val2 ext-val3 "
+        )
+        + ("--no-bool-opt " if sys.version_info.minor >= 9 else "")
+        + "pos1-val1 pos1-val2 pos2-val"
     )
     result = strip_first_entry(
         unparser.get_effective_command_line_invocation()
@@ -151,9 +162,10 @@ def test_get_pretty_command_line_invocation(parser, args) -> None:
     --app-const1 \\
     --app-const2 \\
     -vv \\
-    --ext ext-val1 ext-val2 ext-val3 \\
-    --no-bool-opt \\
-    pos1-val1 pos1-val2 \\
+    --ext ext-val1 ext-val2 ext-val3 \\"""
+    if sys.version_info.minor >= 9:
+        expected += "\n    --no-bool-opt \\"
+    expected += """\n    pos1-val1 pos1-val2 \\
     pos2-val"""
     result = strip_first_line(unparser.get_pretty_command_line_invocation())
     assert result == expected
@@ -211,7 +223,6 @@ def test_get_command_line_invocation_strip_spaces() -> None:
             "--foo bar --foo baz bif",
             ["    --foo bar baz bif"],
         ),
-        (["--foo"], {"action": BooleanOptionalAction}, "--foo", ["    --foo"]),
     ],
 )
 def test__unparse_args(add_args, add_kwargs, args, expected) -> None:
@@ -230,6 +241,19 @@ def test__unparse_args(add_args, add_kwargs, args, expected) -> None:
         assert unparser.args[1:] == expected
 
 
+def test__unparse_args_boolean_optional_action() -> None:
+    if sys.version_info.minor >= 9:
+        parser = ArgumentParser()
+        parser.add_argument("--foo", action=BooleanOptionalAction)
+        try:
+            namespace = parser.parse_args(shlex.split("--foo"))
+        except SystemExit:
+            namespace = Namespace()
+        unparser = ReverseArgumentParser(parser, namespace)
+        unparser._unparse_args()
+        assert unparser.args[1:] == ["    --foo"]
+
+
 def test__unparse_args_already_unparsed() -> None:
     parser = ArgumentParser()
     namespace = Namespace()
@@ -562,11 +586,14 @@ def test__unparse_extend_action() -> None:
     ],
 )
 def test__unparse_boolean_optional_action(default, args, expected) -> None:
-    parser = ArgumentParser()
-    action = parser.add_argument(
-        "--bool-opt", action=BooleanOptionalAction, default=default
-    )
-    namespace = parser.parse_args(shlex.split(args))
-    unparser = ReverseArgumentParser(parser, namespace)
-    unparser._unparse_boolean_optional_action(action)
-    assert unparser.args[1:] == ([expected] if expected is not None else [])
+    if sys.version_info.minor >= 9:
+        parser = ArgumentParser()
+        action = parser.add_argument(
+            "--bool-opt", action=BooleanOptionalAction, default=default
+        )
+        namespace = parser.parse_args(shlex.split(args))
+        unparser = ReverseArgumentParser(parser, namespace)
+        unparser._unparse_boolean_optional_action(action)
+        assert unparser.args[1:] == (
+            [expected] if expected is not None else []
+        )