fix: use local keys for package-repos in core24

Fixes #4743

snapcraft/application.py

@@ -43,7 +43,7 @@
 
 from .legacy_cli import _LIB_NAMES, _ORIGINAL_LIB_NAME_LOG_LEVEL
 from .parts import plugins
-from .parts.yaml_utils import extract_parse_info
+from .parts.yaml_utils import extract_parse_info, get_snap_project
 
 APP_METADATA = AppMetadata(
     name="snapcraft",
@@ -230,6 +230,18 @@ def _create_dispatcher(self) -> craft_cli.Dispatcher:
             default_command=craft_app_commands.lifecycle.PackCommand,
         )
 
+    @override
+    def _get_local_keys_path(self) -> pathlib.Path | None:
+        if self._snapcraft_yaml_path is None:
+            return None
+
+        snap_project = get_snap_project()
+        keys_dir = snap_project.assets_dir / "keys"
+        if keys_dir.is_dir():
+            return keys_dir
+
+        return None
+
 
 def create_app() -> Snapcraft:
     """Create a Snapcraft application with the proper commands."""

tests/spread/core24/package-repositories/test-apt-key-fingerprint/snap/snapcraft.yaml

@@ -25,3 +25,5 @@ package-repositories:
     suites: [focal]
     key-id: 78E1918602959B9C59103100F1831DDAFC42E99D
     url: http://ppa.launchpad.net/snappy-dev/snapcraft-daily/ubuntu
+    # Set an invalid keyserver here to force the use of the local key
+    key-server: keyserver.invalid.com

tests/unit/test_application.py

@@ -17,6 +17,7 @@
 import json
 import os
 import sys
+from pathlib import Path
 from textwrap import dedent
 
 import craft_cli
@@ -467,3 +468,35 @@ def test_run_envvar_invalid(snapcraft_yaml, base, monkeypatch):
         "'SNAPCRAFT_REMOTE_BUILD_STRATEGY'. Valid values are 'disable-fallback' and "
         "'force-fallback'"
     )
+
+
+@pytest.mark.parametrize(
+    ("project_location", "assets_dir", "expected_keys_path"),
+    [
+        # These locations come from yaml_utils._SNAP_PROJECT_FILES
+        # snapcraft.yaml locations where the keys are expected to be in snap/keys
+        ("snapcraft.yaml", "snap", "snap/keys"),
+        ("snap/snapcraft.yaml", "snap", "snap/keys"),
+        (".snapcraft.yaml", "snap", "snap/keys"),
+        # snapcraft.yaml location where the keys are expected to be somewhere else
+        ("build-aux/snap/snapcraft.yaml", "build-aux/snap", "build-aux/snap/keys"),
+    ],
+)
+def test_local_keys_path(new_dir, project_location, assets_dir, expected_keys_path):
+    """Check that _get_local_keys_path() is correct given the location of snapcraft.yaml."""
+    snap_dir = new_dir / Path(project_location).parent
+    snap_dir.mkdir(exist_ok=True, parents=True)
+
+    # The project itself doesn't really matter, but must exist
+    project_yaml = snap_dir / "snapcraft.yaml"
+    project_yaml.write_text(PARSE_INFO_PROJECT)
+
+    app = application.create_app()
+    keys_dir = Path(assets_dir) / "keys"
+
+    # If the keys dir doesn't exist the method should return None
+    assert not keys_dir.is_dir()
+    assert app._get_local_keys_path() is None
+
+    keys_dir.mkdir(exist_ok=True, parents=True)
+    assert app._get_local_keys_path() == Path(expected_keys_path)