Simplify CandidateEvaluator.evaluate_link().

src/pip/_internal/index.py

@@ -290,12 +290,15 @@ def _is_wheel_supported(self, wheel):
  # type: (Wheel) -> bool
  return wheel.supported(self._valid_tags)
 
- def evaluate_link(self, link, search):
- # type: (Link, Search) -> Optional[InstallationCandidate]
+ def _evaluate_link(self, link, search):
+ # type: (Link, Search) -> Tuple[bool, Optional[str]]
  """
  Determine whether a link is a candidate for installation.
 
- Returns an InstallationCandidate if so, otherwise None.
+ :return: A tuple (is_candidate, result), where `result` is (1) a
+ version string if `is_candidate` is True, and (2) if
+ `is_candidate` is False, an optional string to log the reason
+ the link fails to qualify.
  """
  version = None
  if link.egg_fragment:
@@ -304,61 +307,43 @@ def evaluate_link(self, link, search):
  else:
  egg_info, ext = link.splitext()
  if not ext:
- self._log_skipped_link(link, 'not a file')
- return None
+ return (False, 'not a file')
  if ext not in SUPPORTED_EXTENSIONS:
- self._log_skipped_link(
- link, 'unsupported archive format: %s' % ext,
- )
- return None
+ return (False, 'unsupported archive format: %s' % ext)
  if "binary" not in search.formats and ext == WHEEL_EXTENSION:
- self._log_skipped_link(
- link, 'No binaries permitted for %s' % search.supplied,
- )
- return None
+ reason = 'No binaries permitted for %s' % search.supplied
+ return (False, reason)
  if "macosx10" in link.path and ext == '.zip':
- self._log_skipped_link(link, 'macosx10 one')
- return None
+ return (False, 'macosx10 one')
  if ext == WHEEL_EXTENSION:
  try:
  wheel = Wheel(link.filename)
  except InvalidWheelFilename:
- self._log_skipped_link(link, 'invalid wheel filename')
- return None
+ return (False, 'invalid wheel filename')
  if canonicalize_name(wheel.name) != search.canonical:
- self._log_skipped_link(
- link, 'wrong project name (not %s)' % search.supplied)
- return None
+ reason = 'wrong project name (not %s)' % search.supplied
+ return (False, reason)
 
  if not self._is_wheel_supported(wheel):
- self._log_skipped_link(
- link, 'it is not compatible with this Python')
- return None
+ return (False, 'it is not compatible with this Python')
 
  version = wheel.version
 
  # This should be up by the search.ok_binary check, but see issue 2700.
  if "source" not in search.formats and ext != WHEEL_EXTENSION:
- self._log_skipped_link(
- link, 'No sources permitted for %s' % search.supplied,
- )
- return None
+ return (False, 'No sources permitted for %s' % search.supplied)
 
  if not version:
  version = _egg_info_matches(egg_info, search.canonical)
  if not version:
- self._log_skipped_link(
- link, 'Missing project version for %s' % search.supplied)
- return None
+ return (False, 'Missing project version for %s' % search.supplied)
 
  match = self._py_version_re.search(version)
  if match:
  version = version[:match.start()]
  py_version = match.group(1)
  if py_version != sys.version[:3]:
- self._log_skipped_link(
- link, 'Python version is incorrect')
- return None
+ return (False, 'Python version is incorrect')
  try:
  support_this_python = check_requires_python(
  link.requires_python, version_info=sys.version_info[:3],
@@ -372,10 +357,29 @@ def evaluate_link(self, link, search):
  logger.debug("The package %s is incompatible with the python "
  "version in use. Acceptable python versions are: %s",
  link, link.requires_python)
- return None
+ # Return None for the reason text to suppress calling
+ # _log_skipped_link().
+ return (False, None)
+
  logger.debug('Found link %s, version: %s', link, version)
 
- return InstallationCandidate(search.supplied, version, link)
+ return (True, version)
+
+ def get_install_candidate(self, link, search):
+ # type: (Link, Search) -> Optional[InstallationCandidate]
+ """
+ If the link is a candidate for install, convert it to an
+ InstallationCandidate and return it. Otherwise, return None.
+ """
+ is_candidate, result = self._evaluate_link(link, search=search)
+ if not is_candidate:
+ if result:
+ self._log_skipped_link(link, reason=result)
+ return None
+
+ return InstallationCandidate(
+ search.supplied, location=link, version=result,
+ )
 
  def _sort_key(self, candidate):
  # type: (InstallationCandidate) -> CandidateSortingKey
@@ -776,7 +780,8 @@ def find_all_candidates(self, project_name):
  This checks index_urls and find_links.
  All versions found are returned as an InstallationCandidate list.
 
- See evaluate_link() for details on which files are accepted
+ See CandidateEvaluator._evaluate_link() for details on which files
+ are accepted.
  """
  index_locations = self._get_index_urls_locations(project_name)
  index_file_loc, index_url_loc = self._sort_locations(index_locations)
@@ -976,7 +981,8 @@ def _package_versions(
  # type: (...) -> List[InstallationCandidate]
  result = []
  for link in self._sort_links(links):
- candidate = self.candidate_evaluator.evaluate_link(link, search)
+ candidate = self.candidate_evaluator.get_install_candidate(
+ link, search)
  if candidate is not None:
  result.append(candidate)
  return result

tests/unit/test_finder.py

@@ -489,7 +489,7 @@ def test_evaluate_link__match(self, url):
  canonical=self.canonical_name,
  formats=['source', 'binary'],
  )
- result = self.evaluator.evaluate_link(link, search)
+ result = self.evaluator.get_install_candidate(link, search)
  expected = InstallationCandidate(self.search_name, self.version, link)
  assert result == expected, result
 
@@ -510,7 +510,7 @@ def test_evaluate_link__substring_fails(self, url):
  canonical=self.canonical_name,
  formats=['source', 'binary'],
  )
- result = self.evaluator.evaluate_link(link, search)
+ result = self.evaluator.get_install_candidate(link, search)
  assert result is None, result