fix(expand-extensions): use the Application's project

Fixes LP bug https://bugs.launchpad.net/snapcraft/+bug/2083964

Instead of parsing the project again itself, expand-extensions now uses
the project provided by the application. The output is changed slightly,
but I believe it reflects a more accurate expansion.

snapcraft/commands/extensions.py

@@ -16,6 +16,7 @@
 
 """Snapcraft extension commands."""
 
+import argparse
 import textwrap
 from typing import Dict, List
 
@@ -114,25 +115,10 @@ class ExpandExtensionsCommand(AppCommand):
         """
     )
 
+    always_load_project = True
+
     @overrides
     def run(self, parsed_args):
-        snap_project = get_snap_project()
-
-        # load yaml file and trigger legacy behavior if base is core, core18, or core20
-        yaml_data = process_yaml(snap_project.project_file)
-
-        # process yaml before unmarshalling the data
-        arch = get_host_architecture()
-        yaml_data_for_arch = apply_yaml(yaml_data, arch, arch)
-
-        # `apply_yaml()` adds or replaces the architectures keyword with an Architecture
-        # object, which does not easily dump to a yaml file
-        yaml_data_for_arch.pop("architectures", None)
-        yaml_data_for_arch.pop("platforms", None)
-
-        # `parse-info` keywords must be removed before unmarshalling, because they are
-        # not part of the Project model
-        extract_parse_info(yaml_data_for_arch)
-
-        project_data = models.Project.unmarshal(yaml_data_for_arch)
-        emit.message(project_data.to_yaml_string())
+        emit.message(
+            self._services.project.to_yaml_string()
+        )

tests/unit/commands/test_expand_extensions.py

@@ -22,7 +22,7 @@
 import pytest
 from craft_platforms import DebianArchitecture
 
-from snapcraft import commands, const
+from snapcraft import application, commands, const
 
 
 @dataclass
@@ -45,7 +45,7 @@ def valid_core_data(request) -> CoreData:
 
 
 @pytest.mark.usefixtures("fake_extension")
-def test_expand_extensions_simple_core22(new_dir, emitter):
+def test_expand_extensions_simple_core22(new_dir, emitter, mocker):
     """Expand an extension for a simple snapcraft.yaml file."""
     with Path("snapcraft.yaml").open("w") as yaml_file:
         print(
@@ -73,8 +73,8 @@ def test_expand_extensions_simple_core22(new_dir, emitter):
             file=yaml_file,
         )
 
-    cmd = commands.ExpandExtensionsCommand(None)
-    cmd.run(Namespace())
+    mocker.patch("sys.argv", ["snapcraft", "expand-extensions"])
+    application.main()
     emitter.assert_message(
         dedent(
             f"""\
@@ -110,7 +110,7 @@ def test_expand_extensions_simple_core22(new_dir, emitter):
 
 
 @pytest.mark.usefixtures("fake_extension")
-def test_expand_extensions_simple(new_dir, emitter, valid_core_data):
+def test_expand_extensions_simple(new_dir, emitter, valid_core_data, mocker):
     """Expand an extension for a simple snapcraft.yaml file."""
     with Path("snapcraft.yaml").open("w") as yaml_file:
         print(
@@ -139,8 +139,8 @@ def test_expand_extensions_simple(new_dir, emitter, valid_core_data):
             file=yaml_file,
         )
 
-    cmd = commands.ExpandExtensionsCommand(None)
-    cmd.run(Namespace())
+    mocker.patch("sys.argv", ["snapcraft", "expand-extensions"])
+    application.main()
     emitter.assert_message(
         dedent(
             f"""\
@@ -216,8 +216,8 @@ def test_expand_extensions_complex_core22(new_dir, emitter, mocker):
             file=yaml_file,
         )
 
-    cmd = commands.ExpandExtensionsCommand(None)
-    cmd.run(Namespace())
+    mocker.patch("sys.argv", ["snapcraft", "expand-extensions"])
+    application.main()
     emitter.assert_message(
         dedent(
             f"""\
@@ -241,9 +241,17 @@ def test_expand_extensions_complex_core22(new_dir, emitter, mocker):
             grade: stable
             architectures:
             - build-on:
-              - {DebianArchitecture.from_host()}
+              - amd64
               build-for:
-              - {DebianArchitecture.from_host()}
+              - amd64
+            - build-on:
+              - arm64
+              build-for:
+              - arm64
+            - build-on:
+              - armhf
+              build-for:
+              - armhf
             apps:
               app1:
                 command: app1
@@ -279,7 +287,10 @@ def test_expand_extensions_complex(new_dir, emitter, mocker, valid_core_data):
                 build-base: {valid_core_data.build_base}
                 confinement: strict
                 grade: {valid_core_data.grade}
-                platforms: [amd64, arm64, armhf]
+                platforms:
+                  amd64:
+                  arm64:
+                  armhf:
 
                 apps:
                   app1:
@@ -301,9 +312,8 @@ def test_expand_extensions_complex(new_dir, emitter, mocker, valid_core_data):
             ),
             file=yaml_file,
         )
-
-    cmd = commands.ExpandExtensionsCommand(None)
-    cmd.run(Namespace())
+    mocker.patch("sys.argv", ["snapcraft", "expand-extensions"])
+    application.main()
     emitter.assert_message(
         dedent(
             f"""\
@@ -313,6 +323,22 @@ def test_expand_extensions_complex(new_dir, emitter, mocker, valid_core_data):
             description: expand a fake extension
             base: {valid_core_data.base}
             build-base: {valid_core_data.build_base}
+            platforms:
+              amd64:
+                build-on:
+                - amd64
+                build-for:
+                - amd64
+              arm64:
+                build-on:
+                - arm64
+                build-for:
+                - arm64
+              armhf:
+                build-on:
+                - armhf
+                build-for:
+                - armhf
             parts:
               nil:
                 plugin: nil

tests/unit/conftest.py

@@ -44,6 +44,12 @@ def reset_plugins():
     plugins.unregister_all()
 
 
+@pytest.fixture(autouse=True)
+def set_debug(monkeypatch):
+    # Instead of eating exceptions, calls to app.run() will raise them.
+    monkeypatch.setenv("CRAFT_DEBUG", "1")
+
+
 @pytest.fixture
 def snapcraft_yaml(new_dir):
     """Return a fixture that can write a snapcraft.yaml."""