Merge pull request #33 from elcaminoreal/add_error_and_subcommand

add better error behavior and subcommand detection

pyproject.toml

@@ -6,7 +6,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "gather"
-version = "2024.1.5.1"
+version = "2024.1.5.2"
 description = "A gatherer"
 readme = "README.rst"
 authors = [{name = "Moshe Zadka", email = "[email protected]"}]

src/gather/commands.py

@@ -116,7 +116,15 @@ def wrapped_dry_run(cmdargs, **kwargs):
     args.orig_run = orig_run
 
 
-def run_maybe_dry(*, parser, argv=sys.argv, env=os.environ, sp_run=subprocess.run):
+def run_maybe_dry(
+    *,
+    parser,
+    argv=sys.argv,
+    env=os.environ,
+    sp_run=subprocess.run,
+    is_subcommand=False,
+    prefix=None,
+):
     """
     Run commands that only take ``args``.
 
@@ -128,11 +136,26 @@ def run_maybe_dry(*, parser, argv=sys.argv, env=os.environ, sp_run=subprocess.ru
     * ``safe_run``: Run with logging
     * ``orig_run``: Original function
     """
+
+    def error(args):
+        parser.print_help()
+        raise SystemExit(1)
+
+    argv = list(argv)
+    if is_subcommand:
+        argv[0:0] = [prefix or "base-command"]
+        argv[1] = argv[1].rsplit("/", 1)[-1]
+        if prefix is not None:
+            argv[1] = argv[1].removeprefix(prefix + "-")
+
     args = parser.parse_args(argv[1:])
     args.orig_run = sp_run
     args.env = env
     _make_safe_run(args)
-    command = args.__gather_command__
+    try:
+        command = args.__gather_command__
+    except AttributeError:
+        command = error
     return command(
         args=args,
     )

src/gather/tests/test_commands.py

@@ -138,6 +138,32 @@ def test_custom_parser(self):
             contains_string("custom help message"),
         )
 
+
+class CommandMaybeDryTest(unittest.TestCase):
+
+    """Test run_maybe_dry"""
+
+    def test_error(self):
+        """Help message is printed out"""
+        parser = commands.set_parser(collected=MAYBE_DRY_COMMANDS_COLLECTOR.collect())
+        mock_output = mock.patch("sys.stdout", new=io.StringIO())
+        self.addCleanup(mock_output.stop)
+        fake_stdout = mock_output.start()
+        assert_that(
+            calling(commands.run_maybe_dry).with_args(
+                parser=parser,
+                argv=["command"],
+                env={},
+                sp_run=subprocess.run,
+            ),
+            raises(SystemExit),
+        )
+        output = fake_stdout.getvalue()
+        assert_that(
+            output,
+            contains_string("usage"),
+        )
+
     def test_with_dry(self):
         """Test running command in dry-run mode"""
         parser = commands.set_parser(collected=MAYBE_DRY_COMMANDS_COLLECTOR.collect())
@@ -203,3 +229,56 @@ def test_with_dry_fail(self):
                 ),
                 raises(subprocess.CalledProcessError),
             )
+
+    def test_with_subcommand(self):
+        """Test running command as subcommand"""
+        parser = commands.set_parser(collected=MAYBE_DRY_COMMANDS_COLLECTOR.collect())
+        with contextlib.ExitStack() as stack:
+            tmp_dir = pathlib.Path(stack.enter_context(tempfile.TemporaryDirectory()))
+            commands.run_maybe_dry(
+                parser=parser,
+                argv=[
+                    "write-safely",
+                    "--output-dir",
+                    os.fspath(tmp_dir),
+                    "--no-dry-run",
+                ],
+                is_subcommand=True,
+                env={},
+                sp_run=subprocess.run,
+            )
+            contents = {child.name: child.read_text() for child in tmp_dir.iterdir()}
+        assert_that(
+            contents,
+            all_of(
+                has_entry("unsafe.txt", "2"),
+                has_entry("safe.txt", "2"),
+            ),
+        )
+
+    def test_with_prefixed_subcommand(self):
+        """Test running command as subcommand"""
+        parser = commands.set_parser(collected=MAYBE_DRY_COMMANDS_COLLECTOR.collect())
+        with contextlib.ExitStack() as stack:
+            tmp_dir = pathlib.Path(stack.enter_context(tempfile.TemporaryDirectory()))
+            commands.run_maybe_dry(
+                parser=parser,
+                argv=[
+                    "command-write-safely",
+                    "--output-dir",
+                    os.fspath(tmp_dir),
+                    "--no-dry-run",
+                ],
+                is_subcommand=True,
+                prefix="command",
+                env={},
+                sp_run=subprocess.run,
+            )
+            contents = {child.name: child.read_text() for child in tmp_dir.iterdir()}
+        assert_that(
+            contents,
+            all_of(
+                has_entry("unsafe.txt", "2"),
+                has_entry("safe.txt", "2"),
+            ),
+        )