Enable Python warnings during tests and fix all in the code

piptools/repositories/base.py

@@ -12,6 +12,8 @@ class BaseRepository(object):
     def clear_caches(self):
         """Should clear any caches used by the implementation."""
 
+    @abstractmethod
+    @contextmanager
     def freshen_build_caches(self):
         """Should start with fresh build/source caches."""
 

piptools/repositories/local.py

@@ -56,8 +56,10 @@ def DEFAULT_INDEX_URL(self):
     def clear_caches(self):
         self.repository.clear_caches()
 
+    @contextmanager
     def freshen_build_caches(self):
-        self.repository.freshen_build_caches()
+        with self.repository.freshen_build_caches():
+            yield
 
     def find_best_match(self, ireq, prereleases=None):
         key = key_from_ireq(ireq)

piptools/repositories/pypi.py

@@ -87,29 +87,38 @@ def __init__(self, pip_args, cache_dir):
         self._dependencies_cache = {}
 
         # Setup file paths
-        self.freshen_build_caches()
+        self._build_dir = None
+        self._source_dir = None
         self._cache_dir = normalize_path(cache_dir)
         self._download_dir = fs_str(os.path.join(self._cache_dir, "pkgs"))
         if PIP_VERSION[:2] <= (20, 2):
             self._wheel_download_dir = fs_str(os.path.join(self._cache_dir, "wheels"))
 
         self._setup_logging()
 
+    @contextmanager
     def freshen_build_caches(self):
         """
         Start with fresh build/source caches.  Will remove any old build
         caches from disk automatically.
         """
         self._build_dir = TemporaryDirectory(fs_str("build"))
         self._source_dir = TemporaryDirectory(fs_str("source"))
+        try:
+            yield
+        finally:
+            self._build_dir.cleanup()
+            self._build_dir = None
+            self._source_dir.cleanup()
+            self._source_dir = None
 
     @property
     def build_dir(self):
-        return self._build_dir.name
+        return self._build_dir.name if self._build_dir else None
 
     @property
     def source_dir(self):
-        return self._source_dir.name
+        return self._source_dir.name if self._source_dir else None
 
     def clear_caches(self):
         rmtree(self._download_dir, ignore_errors=True)

piptools/resolver.py

@@ -170,7 +170,13 @@ def resolve(self, max_rounds=10):
 
             log.debug("")
             log.debug(magenta("{:^60}".format("ROUND {}".format(current_round))))
-            has_changed, best_matches = self._resolve_one_round()
+            # If a package version (foo==2.0) was built in a previous round,
+            # and in this round a different version of foo needs to be built
+            # (i.e. foo==1.0), the directory will exist already, which will
+            # cause a pip build failure.  The trick is to start with a new
+            # build cache dir for every round, so this can never happen.
+            with self.repository.freshen_build_caches():
+                has_changed, best_matches = self._resolve_one_round()
             log.debug("-" * 60)
             log.debug(
                 "Result of round {}: {}".format(
@@ -180,13 +186,6 @@ def resolve(self, max_rounds=10):
             if not has_changed:
                 break
 
-            # If a package version (foo==2.0) was built in a previous round,
-            # and in this round a different version of foo needs to be built
-            # (i.e. foo==1.0), the directory will exist already, which will
-            # cause a pip build failure.  The trick is to start with a new
-            # build cache dir for every round, so this can never happen.
-            self.repository.freshen_build_caches()
-
         del os.environ["PIP_EXISTS_ACTION"]
 
         # Only include hard requirements and not pip constraints

setup.cfg

@@ -56,6 +56,7 @@ universal = 1
 norecursedirs = .* build dist venv test_data piptools/_compat/*
 testpaths = tests piptools
 filterwarnings =
+    always
     ignore::PendingDeprecationWarning:pip\._vendor.+
     ignore::DeprecationWarning:pip\._vendor.+
 markers =

tests/conftest.py

@@ -41,6 +41,10 @@ def __init__(self):
         with open("tests/test_data/fake-editables.json", "r") as f:
             self.editables = json.load(f)
 
+    @contextmanager
+    def freshen_build_caches(self):
+        yield
+
     def get_hashes(self, ireq):
         # Some fake hashes
         return {

tests/test_cli_compile.py

@@ -196,7 +196,7 @@ def test_redacted_urls_in_verbose_output(runner, option):
         cli,
         [
             "--no-header",
-            "--no-index",
+            "--no-emit-index-url",
             "--no-emit-find-links",
             "--verbose",
             option,

tests/test_repository_pypi.py

@@ -109,23 +109,30 @@ def test_open_local_or_remote_file__remote_file(
     response_file_path.write_bytes(content)
 
     mock_response = mock.Mock()
-    mock_response.raw = response_file_path.open("rb")
-    mock_response.headers = {"content-length": content_length}
+    with response_file_path.open("rb") as fp:
+        mock_response.raw = fp
+        mock_response.headers = {"content-length": content_length}
 
-    with mock.patch.object(session, "get", return_value=mock_response):
-        with open_local_or_remote_file(link, session) as file_stream:
-            assert file_stream.stream.read() == content
-            assert file_stream.size == expected_content_length
+        with mock.patch.object(session, "get", return_value=mock_response):
+            with open_local_or_remote_file(link, session) as file_stream:
+                assert file_stream.stream.read() == content
+                assert file_stream.size == expected_content_length
 
-    mock_response.close.assert_called_once()
+        mock_response.close.assert_called_once()
 
 
 def test_pypirepo_build_dir_is_str(pypi_repository):
-    assert isinstance(pypi_repository.build_dir, str)
+    assert pypi_repository.build_dir is None
+    with pypi_repository.freshen_build_caches():
+        assert isinstance(pypi_repository.build_dir, str)
+    assert pypi_repository.build_dir is None
 
 
 def test_pypirepo_source_dir_is_str(pypi_repository):
-    assert isinstance(pypi_repository.source_dir, str)
+    assert pypi_repository.source_dir is None
+    with pypi_repository.freshen_build_caches():
+        assert isinstance(pypi_repository.source_dir, str)
+    assert pypi_repository.source_dir is None
 
 
 def test_relative_path_cache_dir_is_normalized(from_line):