Add PackageFinder.create(), and simplify PackageFinder().

Author: cjerdonek

src/pip/_internal/cli/base_command.py

@@ -340,7 +340,7 @@ def _build_package_finder(
             )
             index_urls = []
 
-        return PackageFinder(
+        return PackageFinder.create(
             find_links=options.find_links,
             format_control=options.format_control,
             index_urls=index_urls,

src/pip/_internal/commands/list.py

@@ -113,7 +113,7 @@ def _build_package_finder(self, options, index_urls, session):
         """
         Create a package finder appropriate to this list command.
         """
-        return PackageFinder(
+        return PackageFinder.create(
             find_links=options.find_links,
             index_urls=index_urls,
             allow_all_prereleases=options.pre,

src/pip/_internal/index.py

@@ -513,6 +513,39 @@ class PackageFinder(object):
 
     def __init__(
         self,
+        candidate_evaluator,  # type: CandidateEvaluator
+        find_links,  # type: List[str]
+        index_urls,  # type: List[str]
+        secure_origins,  # type: List[SecureOrigin]
+        session,  # type: PipSession
+        allow_all_prereleases=False,  # type: bool
+        format_control=None,  # type: Optional[FormatControl]
+    ):
+        # type: (...) -> None
+        """
+        This constructor is primarily meant to be used by the create() class
+        method and from tests.
+
+        :param candidate_evaluator: A CandidateEvaluator object.
+        :param session: The Session to use to make requests.
+        :param allow_all_prereleases: Whether to allow all pre-releases.
+        :param format_control: A FormatControl object, used to control
+            the selection of source packages / binary packages when consulting
+            the index and links.
+        """
+        format_control = format_control or FormatControl(set(), set())
+
+        self.candidate_evaluator = candidate_evaluator
+        self.find_links = find_links
+        self.index_urls = index_urls
+        self.secure_origins = secure_origins
+        self.session = session
+        self.allow_all_prereleases = allow_all_prereleases
+        self.format_control = format_control
+
+    @classmethod
+    def create(
+        cls,
         find_links,  # type: List[str]
         index_urls,  # type: List[str]
         allow_all_prereleases=False,  # type: bool
@@ -525,9 +558,12 @@ def __init__(
         implementation=None,  # type: Optional[str]
         prefer_binary=False  # type: bool
     ):
-        # type: (...) -> None
+        # type: (...) -> PackageFinder
         """Create a PackageFinder.
 
+        :param trusted_hosts: Domains that we won't emit warnings for when
+            not using HTTPS.
+        :param session: The Session to use to make requests.
         :param format_control: A FormatControl object or None. Used to control
             the selection of source packages / binary packages when consulting
             the index and links.
@@ -547,7 +583,7 @@ def __init__(
         """
         if session is None:
             raise TypeError(
-                "PackageFinder() missing 1 required keyword argument: "
+                "PackageFinder.create() missing 1 required keyword argument: "
                 "'session'"
             )
 
@@ -556,45 +592,34 @@ def __init__(
         # it and if it exists, use the normalized version.
         # This is deliberately conservative - it might be fine just to
         # blindly normalize anything starting with a ~...
-        self.find_links = []  # type: List[str]
+        built_find_links = []  # type: List[str]
         for link in find_links:
             if link.startswith('~'):
                 new_link = normalize_path(link)
                 if os.path.exists(new_link):
                     link = new_link
-            self.find_links.append(link)
-
-        self.index_urls = index_urls
+            built_find_links.append(link)
 
-        self.format_control = format_control or FormatControl(set(), set())
-
-        # Domains that we won't emit warnings for when not using HTTPS
-        self.secure_origins = [
+        secure_origins = [
             ("*", host, "*")
             for host in (trusted_hosts if trusted_hosts else [])
         ]  # type: List[SecureOrigin]
 
-        # Do we want to allow _all_ pre-releases?
-        self.allow_all_prereleases = allow_all_prereleases
-
-        # The Session we'll use to make requests
-        self.session = session
-
         # The valid tags to check potential found wheel candidates against
         valid_tags = get_supported(
             versions=versions,
             platform=platform,
             abi=abi,
             impl=implementation,
         )
-        self.candidate_evaluator = CandidateEvaluator(
+        candidate_evaluator = CandidateEvaluator(
             valid_tags=valid_tags, prefer_binary=prefer_binary,
         )
 
         # If we don't have TLS enabled, then WARN if anyplace we're looking
         # relies on TLS.
         if not HAS_TLS:
-            for link in itertools.chain(self.index_urls, self.find_links):
+            for link in itertools.chain(index_urls, built_find_links):
                 parsed = urllib_parse.urlparse(link)
                 if parsed.scheme == "https":
                     logger.warning(
@@ -604,6 +629,16 @@ def __init__(
                     )
                     break
 
+        return cls(
+            candidate_evaluator=candidate_evaluator,
+            find_links=built_find_links,
+            index_urls=index_urls,
+            secure_origins=secure_origins,
+            session=session,
+            allow_all_prereleases=allow_all_prereleases,
+            format_control=format_control,
+        )
+
     def get_formatted_locations(self):
         # type: () -> str
         lines = []

src/pip/_internal/utils/outdated.py

@@ -122,7 +122,7 @@ def pip_version_check(session, options):
         # Refresh the version if we need to or just see if we need to warn
         if pypi_version is None:
             # Lets use PackageFinder to see what the latest pip version is
-            finder = PackageFinder(
+            finder = PackageFinder.create(
                 find_links=options.find_links,
                 index_urls=[options.index_url] + options.extra_index_urls,
                 allow_all_prereleases=False,  # Explicitly set to False

tests/functional/test_pep517.py

@@ -23,7 +23,7 @@ def test_backend(tmpdir, data):
     req = InstallRequirement(None, None, source_dir=project_dir)
     req.load_pyproject_toml()
     env = BuildEnvironment()
-    finder = PackageFinder([data.backends], [], session=PipSession())
+    finder = PackageFinder.create([data.backends], [], session=PipSession())
     env.install_requirements(finder, ["dummy_backend"], 'normal', "Installing")
     conflicting, missing = env.check_requirements(["dummy_backend"])
     assert not conflicting and not missing

tests/unit/test_build_env.py

@@ -27,7 +27,7 @@ def run_with_build_env(script, setup_script_contents,
             from pip._internal.download import PipSession
             from pip._internal.index import PackageFinder
 
-            finder = PackageFinder([%r], [], session=PipSession())
+            finder = PackageFinder.create([%r], [], session=PipSession())
             build_env = BuildEnvironment()
 
             try:
@@ -59,7 +59,9 @@ def test_build_env_allow_empty_requirements_install():
 def test_build_env_allow_only_one_install(script):
     create_basic_wheel_for_package(script, 'foo', '1.0')
     create_basic_wheel_for_package(script, 'bar', '1.0')
-    finder = PackageFinder([script.scratch_path], [], session=PipSession())
+    finder = PackageFinder.create(
+        [script.scratch_path], [], session=PipSession(),
+    )
     build_env = BuildEnvironment()
     for prefix in ('normal', 'overlay'):
         build_env.install_requirements(finder, ['foo'], prefix,