feat: pass the app_config to pre_parse_args() (#541)

This lets commands be able to always rely on `self.config` existing, even
when running `fill_parser()` for help output.

Fixes #530

craft_application/application.py

@@ -425,15 +425,18 @@ def _get_dispatcher(self) -> craft_cli.Dispatcher:
 
         try:
             craft_cli.emit.trace("pre-parsing arguments...")
+            app_config = self.app_config
             # Workaround for the fact that craft_cli requires a command.
             # https://github.com/canonical/craft-cli/issues/141
             if "--version" in sys.argv or "-V" in sys.argv:
                 try:
-                    global_args = dispatcher.pre_parse_args(["pull", *sys.argv[1:]])
+                    global_args = dispatcher.pre_parse_args(
+                        ["pull", *sys.argv[1:]], app_config
+                    )
                 except craft_cli.ArgumentParsingError:
-                    global_args = dispatcher.pre_parse_args(sys.argv[1:])
+                    global_args = dispatcher.pre_parse_args(sys.argv[1:], app_config)
             else:
-                global_args = dispatcher.pre_parse_args(sys.argv[1:])
+                global_args = dispatcher.pre_parse_args(sys.argv[1:], app_config)
 
             if global_args.get("version"):
                 craft_cli.emit.message(f"{self.app.name} {self.app.version}")

craft_application/commands/base.py

@@ -18,6 +18,7 @@
 
 import abc
 import argparse
+import warnings
 from typing import Any, Optional, Protocol, final
 
 from craft_cli import BaseCommand, emit
@@ -55,8 +56,11 @@ class AppCommand(BaseCommand):
 
     def __init__(self, config: dict[str, Any] | None) -> None:
         if config is None:
-            # This should only be the case when the command is not going to be run.
-            # For example, when requesting help on the command.
+            warnings.warn(
+                "Creating an AppCommand without a config dict is pending deprecation.",
+                PendingDeprecationWarning,
+                stacklevel=3,
+            )
             emit.trace("Not completing command configuration")
             return
 

docs/reference/changelog.rst

@@ -4,6 +4,15 @@
 Changelog
 *********
 
+4.4.0 (2024-Oct-XX)
+-------------------
+
+Application
+===========
+
+- ``AppCommand`` subclasses now will always receive a valid ``app_config``
+  dict.
+
 4.3.0 (2024-Oct-11)
 -------------------
 

pyproject.toml

@@ -4,7 +4,7 @@ description = "A framework for *craft applications."
 dynamic = ["version", "readme"]
 dependencies = [
     "craft-archives>=2.0.0",
-    "craft-cli>=2.6.0",
+    "craft-cli>=2.9.0",
     "craft-grammar>=2.0.0",
     "craft-parts>=2.1.1",
     "craft-platforms>=0.3.1",

tests/unit/commands/test_base.py

@@ -65,11 +65,11 @@ def test_get_managed_cmd(fake_command, verbosity, app_metadata):
 
 def test_without_config(emitter):
     """Test that a command can be initialised without a config.
-
-    This is necessary for providing per-command help.
+    This is pending deprecation but still supported.
     """
 
-    command = base.AppCommand(None)
+    with pytest.deprecated_call():
+        command = base.AppCommand(None)
 
     emitter.assert_trace("Not completing command configuration")
     assert not hasattr(command, "_app")

tests/unit/test_application.py

@@ -49,6 +49,7 @@
     services,
     util,
 )
+from craft_application.commands import AppCommand
 from craft_application.models import BuildInfo
 from craft_application.util import (
     get_host_architecture,  # pyright: ignore[reportGeneralTypeIssues]
@@ -2141,3 +2142,35 @@ def test_clean_platform(monkeypatch, tmp_path, app_metadata, fake_services, mock
         base=bases.BaseName("ubuntu", "24.04"),
     )
     mocked_clean.assert_called_once_with(mocker.ANY, mocker.ANY, expected_info)
+
+
+class AppConfigCommand(AppCommand):
+
+    name: str = "app-config"
+    help_msg: str = "Help text"
+    overview: str = "Overview"
+
+    def fill_parser(self, parser: argparse.ArgumentParser) -> None:
+
+        name = self._app.name
+        parser.add_argument(
+            "app-name",
+            help=f"The name of the app, which is {name!r}.",
+        )
+
+
+@pytest.mark.usefixtures("emitter")
+def test_app_config_in_help(
+    monkeypatch,
+    capsys,
+    app,
+):
+    app.add_command_group("Test", [AppConfigCommand])
+    monkeypatch.setattr(sys, "argv", ["testcraft", "app-config", "-h"])
+
+    with pytest.raises(SystemExit):
+        app.run()
+
+    expected = "app-name:  The name of the app, which is 'testcraft'."
+    _, err = capsys.readouterr()
+    assert expected in err