apply review comments, add test

src/poetry_plugin_export/command.py

@@ -1,15 +1,21 @@
 from __future__ import annotations
 
 from pathlib import Path
+from typing import TYPE_CHECKING
 
 from cleo.helpers import option
+from packaging.utils import NormalizedName
 from packaging.utils import canonicalize_name
 from poetry.console.commands.group_command import GroupCommand
 from poetry.core.packages.dependency_group import MAIN_GROUP
 
 from poetry_plugin_export.exporter import Exporter
 
 
+if TYPE_CHECKING:
+    from collections.abc import Iterable
+
+
 class ExportCommand(GroupCommand):
     name = "export"
     description = "Exports the lock file to alternative formats."
@@ -43,8 +49,8 @@ class ExportCommand(GroupCommand):
             flag=False,
             multiple=True,
         ),
-        option("with-credentials", None, "Include credentials for extra indices."),
         option("all-extras", None, "Include all sets of extra dependencies."),
+        option("with-credentials", None, "Include credentials for extra indices."),
     ]
 
     @property
@@ -95,6 +101,7 @@ def handle(self) -> int:
             )
             return 1
 
+        extras: Iterable[NormalizedName]
         if self.option("all-extras"):
             extras = self.poetry.package.extras.keys()
         else:

tests/command/test_command_export.py

@@ -227,6 +227,17 @@ def test_export_with_all_extras(tester: CommandTester, do_lock: None) -> None:
     assert f"qux==1.2.0 ; {MARKER_PY}" in output
 
 
+def test_extras_conflicts_all_extras(tester: CommandTester, do_lock: None) -> None:
+    tester.execute("--extras bar --all-extras")
+
+    assert tester.status_code == 1
+    assert (
+        tester.io.fetch_error()
+        == "You cannot specify explicit `--extras` while exporting using"
+        " `--all-extras`.\n"
+    )
+
+
 def test_export_with_urls(
     monkeypatch: MonkeyPatch, tester: CommandTester, poetry: Poetry
 ) -> None: