fix(strict-deps): fail if venv is inconsistent

This runs `pip check` to ensure that all the packages in the charm
virtualenv have all of their required dependencies, failing the build
if they do not.

Fixes #1781

charmcraft/charm_builder.py

@@ -1,4 +1,4 @@
-# Copyright 2020-2023 Canonical Ltd.
+# Copyright 2020-2024 Canonical Ltd.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -61,18 +61,18 @@ def __init__(
         installdir: pathlib.Path,
         entrypoint: pathlib.Path,
         allow_pip_binary: bool = None,
-        binary_python_packages: list[str] = None,
-        python_packages: list[str] = None,
-        requirements: list[pathlib.Path] = None,
+        binary_python_packages: list[str] | None = None,
+        python_packages: list[str] | None = None,
+        requirements: list[pathlib.Path] | None = None,
         strict_dependencies: bool = False,
     ) -> None:
         self.builddir = builddir
         self.installdir = installdir
         self.entrypoint = entrypoint
         self.allow_pip_binary = allow_pip_binary
-        self.binary_python_packages = binary_python_packages
-        self.python_packages = python_packages
-        self.requirement_paths = requirements
+        self.binary_python_packages = binary_python_packages or []
+        self.python_packages = python_packages or []
+        self.requirement_paths = requirements or []
         self.strict_dependencies = strict_dependencies
         self.ignore_rules = self._load_juju_ignore()
         self.ignore_rules.extend_patterns([f"/{const.STAGING_VENV_DIRNAME}"])
@@ -227,7 +227,7 @@ def _calculate_dependencies_hash(self):
         return hashlib.sha1(deps_mashup.encode("utf8")).hexdigest()
 
     @instrum.Timer("Installing dependencies")
-    def _install_dependencies(self, staging_venv_dir):
+    def _install_dependencies(self, staging_venv_dir: pathlib.Path):
         """Install all dependencies in a specific directory."""
         # create virtualenv using the host environment python
         with instrum.Timer("Creating venv"):
@@ -309,6 +309,8 @@ def _install_strict_dependencies(self, pip_cmd: str) -> None:
                 binary_deps=self.binary_python_packages or [],
             )
         )
+        # Validate that the environment is consistent.
+        _process_run([pip_cmd, "check"])
 
     def handle_dependencies(self):
         """Handle from-directory and virtualenv dependencies."""

tests/integration/test_charm_builder.py

@@ -0,0 +1,84 @@
+# Copyright 2024 Canonical Ltd.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# For further info, check https://github.com/canonical/charmcraft
+"""Integration tests for CharmBuilder."""
+
+
+import pathlib
+
+import pytest
+from charmcraft import charm_builder
+
+
+@pytest.mark.parametrize(
+    "requirements",
+    [
+        ["ops==2.15.0"],  # Requires pyyaml and websocket-client
+    ]
+)
+def test_install_strict_dependencies_pip_check_error(
+    new_path: pathlib.Path, requirements: list[str]
+):
+    build_dir = new_path / "build"
+    install_dir = new_path / "install"
+    entrypoint = build_dir / "entrypoint.py"
+
+    build_dir.mkdir()
+    install_dir.mkdir()
+
+    requirements_file = build_dir / "requirements.txt"
+    requirements_file.write_text("\n".join(requirements))
+
+    builder = charm_builder.CharmBuilder(
+        builddir=build_dir,
+        installdir=install_dir,
+        entrypoint=entrypoint,
+        requirements=[requirements_file],
+        strict_dependencies=True
+    )
+
+    with pytest.raises(RuntimeError, match="failed with retcode 1") as exc_info:
+        builder.handle_dependencies()
+
+
+@pytest.mark.parametrize(
+    "requirements",
+    [
+        ["craft-platforms==0.1.0"],  # No dependencies
+    ]
+)
+def test_install_strict_dependencies_pip_check_success(
+    new_path: pathlib.Path, requirements: list[str]
+):
+    build_dir = new_path / "build"
+    install_dir = new_path / "install"
+    entrypoint = build_dir / "entrypoint.py"
+
+    build_dir.mkdir()
+    install_dir.mkdir()
+
+    requirements_file = build_dir / "requirements.txt"
+    requirements_file.write_text("\n".join(requirements))
+
+    builder = charm_builder.CharmBuilder(
+        builddir=build_dir,
+        installdir=install_dir,
+        entrypoint=entrypoint,
+        requirements=[requirements_file],
+        strict_dependencies=True
+    )
+
+    with pytest.raises(RuntimeError, match="failed with retcode 1") as exc_info:
+        builder.handle_dependencies()

tests/unit/test_charm_builder.py

@@ -1,4 +1,4 @@
-# Copyright 2023 Canonical Ltd.
+# Copyright 2023-2024 Canonical Ltd.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -105,6 +105,10 @@ def test_install_strict_dependencies_success(
         "--no-binary=:all:",
         "--requirement=requirements.txt",
     ]
-    fake_process.register(expected_command, returncode=0)
+    install_cmd = fake_process.register(expected_command, returncode=0)
+    check_cmd = fake_process.register(["/pip", "check"], returncode=0)
 
     builder._install_strict_dependencies("/pip")
+
+    assert install_cmd.call_count() == 1
+    assert check_cmd.call_count() == 1