Merge pull request #7664 from stealthycoin/missing-flit-core

Add error message when flit_core is not installed

backends/build_system/utils.py

@@ -12,6 +12,8 @@
 # language governing permissions and limitations under the License.
 import os
 import re
+import sys
+import shlex
 import json
 import shutil
 import subprocess
@@ -21,6 +23,7 @@
 
 from constants import ROOT_DIR
 from constants import IS_WINDOWS
+from constants import BOOTSTRAP_REQUIREMENTS
 
 
 PACKAGE_NAME = re.compile(r"(?P<name>[A-Za-z][A-Za-z0-9_\.\-]+)(?P<rest>.+)")
@@ -34,6 +37,39 @@
 }
 
 
+class UnmetDependenciesException(Exception):
+    def __init__(self, unmet_deps, in_venv, reason=None):
+        pip_install_command_args = ["-m", "pip", "install", "--prefer-binary"]
+        msg = "Environment requires following Python dependencies:\n\n"
+        for package, actual_version, required in unmet_deps:
+            msg += (
+                f"{package} (required: {required.constraints}) "
+                f"(version installed: {actual_version})\n"
+            )
+            pip_install_command_args.append(f'{package}{required.string_constraints()}')
+
+        if reason:
+            msg += f"\n{reason}\n"
+
+        msg += (
+            "\n"
+            "We recommend using --with-download-deps flag to automatically create a "
+            "virtualenv and download the dependencies.\n\n"
+            "If you want to manage the dependencies yourself instead, run the following "
+            "pip command:\n"
+        )
+        msg += f"{sys.executable} {shlex.join(pip_install_command_args)}\n"
+
+        if not in_venv:
+            msg += (
+                "\nWe noticed you are not in a virtualenv.\nIf not using --with-download-deps "
+                "we highly recommend using a virtualenv to prevent dependencies "
+                "from being installed into your global "
+                "Python environment.\n"
+            )
+        super().__init__(msg)
+
+
 @contextlib.contextmanager
 def cd(dirname):
     original = os.getcwd()
@@ -121,7 +157,11 @@ def _parse_req_line(line: str):
 
 
 def get_install_requires():
-    import flit_core.buildapi
+    try:
+        import flit_core.buildapi
+    except ImportError:
+        flit_core_exception = get_flit_core_unmet_exception()
+        raise flit_core_exception
 
     with cd(ROOT_DIR):
         requires = flit_core.buildapi.get_requires_for_build_wheel()
@@ -140,6 +180,23 @@ def get_install_requires():
     return dependencies
 
 
+def get_flit_core_unmet_exception():
+    in_venv = sys.prefix != sys.base_prefix
+    with open(BOOTSTRAP_REQUIREMENTS, 'r') as f:
+        flit_core_req = [
+            l for l in f.read().split('\n')
+            if 'flit_core' in l
+        ]
+    return UnmetDependenciesException(
+        [('flit_core', None, list(parse_requirements(flit_core_req))[0])],
+        in_venv,
+        reason=(
+            'flit_core is needed ahead of time in order to parse the '
+            'rest of the requirements.'
+        )
+    )
+
+
 class Utils:
     def isdir(self, path: str) -> bool:
         return os.path.isdir(path)

backends/build_system/validate_env.py

@@ -12,7 +12,6 @@
 # language governing permissions and limitations under the License.
 import re
 import sys
-import shlex
 from pathlib import Path
 import importlib.metadata
 
@@ -21,6 +20,8 @@
     PORTABLE_EXE_REQUIREMENTS,
 )
 from utils import get_install_requires, parse_requirements
+from utils import UnmetDependenciesException
+
 
 ROOT = Path(__file__).parents[2]
 PYPROJECT = ROOT / "pyproject.toml"
@@ -30,36 +31,6 @@
 EXTRACT_DEPENDENCIES_RE = re.compile(r'"(.+)"')
 
 
-class UnmetDependenciesException(Exception):
-    def __init__(self, unmet_deps, in_venv):
-        pip_install_command_args = ["-m", "pip", "install", "--prefer-binary"]
-        msg = "Environment requires following Python dependencies:\n\n"
-        for package, actual_version, required in unmet_deps:
-            msg += (
-                f"{package} (required: {required.constraints}) "
-                f"(version installed: {actual_version})\n"
-            )
-            pip_install_command_args.append(f'{package}{required.string_constraints()}')
-
-        msg += (
-            "\n"
-            "We recommend using --with-download-deps flag to automatically create a "
-            "virtualenv and download the dependencies.\n\n"
-            "If you want to manage the dependencies yourself instead, run the following "
-            "pip command:\n"
-        )
-        msg += f"{sys.executable} {shlex.join(pip_install_command_args)}\n"
-
-        if not in_venv:
-            msg += (
-                "\nWe noticed you are not in a virtualenv.\nIf not using --with-download-deps "
-                "we highly recommend using a virtualenv to prevent dependencies "
-                "from being installed into your global "
-                "Python environment.\n"
-            )
-        super().__init__(msg)
-
-
 def validate_env(target_artifact):
     requirements = _get_requires_list(target_artifact)
     unmet_deps = _get_unmet_dependencies(requirements)

tests/backends/build_system/functional/test_utils.py

@@ -11,6 +11,7 @@
 # ANY KIND, either express or implied. See the License for the specific
 # language governing permissions and limitations under the License.
 import os
+import sys
 import json
 import platform
 from typing import List
@@ -21,6 +22,7 @@
 from build_system.utils import parse_requirements
 from build_system.utils import ParseError
 from build_system.utils import Requirement
+from build_system.utils import UnmetDependenciesException
 
 from tests.backends.build_system.markers import skip_if_windows, if_windows
 
@@ -241,4 +243,41 @@ def test_create_venv_windows(self, utils: Utils, tmp_path):
         )
 
     def assert_dir_has_content(self, path: str, expected_files: List[str]):
-        assert set(expected_files).issubset(set(os.listdir(path)))
+        assert set(l.lower() for l in expected_files).issubset(
+            set(l.lower() for l in os.listdir(path))
+        )
+
+
+@pytest.fixture
+def unmet_error(request):
+    error = UnmetDependenciesException([
+        ('colorama', '1.0', Requirement('colorama', '>=2.0', '<3.0')),
+    ], **request.param)
+    return str(error)
+
+
+class TestUnmetDependencies:
+    @pytest.mark.parametrize('unmet_error', [{'in_venv': False}], indirect=True)
+    def test_in_error_message(self, unmet_error):
+        assert (
+            "colorama (required: ('>=2.0', '<3.0')) (version installed: 1.0)"
+        ) in unmet_error
+        assert (
+            f"{sys.executable} -m pip install --prefer-binary 'colorama>=2.0,<3.0'"
+        ) in unmet_error
+
+    @pytest.mark.parametrize('unmet_error', [{'in_venv': False}], indirect=True)
+    def test_not_in_venv(self, unmet_error):
+        assert 'We noticed you are not in a virtualenv.' in unmet_error
+
+    @pytest.mark.parametrize('unmet_error', [{'in_venv': True}], indirect=True)
+    def test_in_venv(self, unmet_error):
+        assert 'We noticed you are not in a virtualenv.' not in unmet_error
+
+    @pytest.mark.parametrize(
+        'unmet_error',
+        [{'in_venv': False, 'reason': "custom reason message"}],
+        indirect=True,
+    )
+    def test_custom_reason(self, unmet_error):
+        assert 'custom reason message' in unmet_error

tests/backends/build_system/unit/test_validate_env.py

@@ -2,32 +2,4 @@
 
 import pytest
 
-from backends.build_system.validate_env import UnmetDependenciesException
 from backends.build_system.utils import Requirement
-
-
-@pytest.fixture
-def unmet_error(request):
-    error = UnmetDependenciesException([
-        ('colorama', '1.0', Requirement('colorama', '>=2.0', '<3.0')),
-    ], in_venv=request.param)
-    return str(error)
-
-
-class TestUnmetDependencies:
-    @pytest.mark.parametrize('unmet_error', [False], indirect=True)
-    def test_in_error_message(self, unmet_error):
-        assert (
-            "colorama (required: ('>=2.0', '<3.0')) (version installed: 1.0)"
-        ) in unmet_error
-        assert (
-            f"{sys.executable} -m pip install --prefer-binary 'colorama>=2.0,<3.0'"
-        ) in unmet_error
-
-    @pytest.mark.parametrize('unmet_error', [False], indirect=True)
-    def test_not_in_venv(self, unmet_error):
-        assert 'We noticed you are not in a virtualenv.' in unmet_error
-
-    @pytest.mark.parametrize('unmet_error', [True], indirect=True)
-    def test_in_venv(self, unmet_error):
-        assert 'We noticed you are not in a virtualenv.' not in unmet_error