Remove pkg_resources usages from 'pip show'

src/pip/_internal/commands/show.py

@@ -1,14 +1,14 @@
+import csv
 import logging
 import os
-from email.parser import FeedParser
 from optparse import Values
-from typing import Dict, Iterator, List
+from typing import Dict, Iterator, List, Optional
 
-from pip._vendor import pkg_resources
 from pip._vendor.packaging.utils import canonicalize_name
 
 from pip._internal.cli.base_command import Command
 from pip._internal.cli.status_codes import ERROR, SUCCESS
+from pip._internal.metadata import BaseDistribution, get_default_environment
 from pip._internal.utils.misc import write_output
 
 logger = logging.getLogger(__name__)
@@ -58,85 +58,77 @@ def search_packages_info(query):
     pip generated 'installed-files.txt' in the distributions '.egg-info'
     directory.
     """
-    installed = {}
-    for p in pkg_resources.working_set:
-        installed[canonicalize_name(p.project_name)] = p
+    env = get_default_environment()
 
+    installed = {
+        dist.canonical_name: dist
+        for dist in env.iter_distributions()
+    }
     query_names = [canonicalize_name(name) for name in query]
     missing = sorted(
         [name for name, pkg in zip(query, query_names) if pkg not in installed]
     )
     if missing:
         logger.warning('Package(s) not found: %s', ', '.join(missing))
 
-    def get_requiring_packages(package_name):
+    def get_requiring_packages(canonical_name):
         # type: (str) -> List[str]
-        canonical_name = canonicalize_name(package_name)
         return [
-            pkg.project_name for pkg in pkg_resources.working_set
-            if canonical_name in
-               [canonicalize_name(required.name) for required in
-                pkg.requires()]
+            dist.canonical_name
+            for dist in env.iter_distributions()
+            if canonical_name in {
+                canonicalize_name(d.name) for d in dist.iter_dependencies()
+            }
         ]
 
-    for dist in [installed[pkg] for pkg in query_names if pkg in installed]:
+    def _files_from_record(dist: BaseDistribution) -> Optional[Iterator[str]]:
+        try:
+            text = dist.read_text('RECORD')
+        except FileNotFoundError:
+            return None
+        return (row[0] for row in csv.reader(text.splitlines()))
+
+    def _files_from_installed_files(dist: BaseDistribution) -> Optional[Iterator[str]]:
+        try:
+            text = dist.read_text('installed-files.txt')
+        except FileNotFoundError:
+            return None
+        return (p for p in text.splitlines(keepends=False) if p)
+
+    for query_name in query_names:
+        try:
+            dist = installed[query_name]
+        except KeyError:
+            continue
         package = {
             'name': dist.project_name,
             'version': dist.version,
             'location': dist.location,
-            'requires': [dep.project_name for dep in dist.requires()],
-            'required_by': get_requiring_packages(dist.project_name)
+            'requires': [req.nameroject_name for req in dist.iter_dependencies()],
+            'required_by': get_requiring_packages(dist.canonical_name),
+            'installer': dist.installer,
+            'metadata-version': dist.metadata_version,
+            'classifiers': dist.metadata.get_all('Classifiers'),
         }
-        file_list = None
-        metadata = ''
-        if isinstance(dist, pkg_resources.DistInfoDistribution):
-            # RECORDs should be part of .dist-info metadatas
-            if dist.has_metadata('RECORD'):
-                lines = dist.get_metadata_lines('RECORD')
-                paths = [line.split(',')[0] for line in lines]
-                paths = [os.path.join(dist.location, p) for p in paths]
-                file_list = [os.path.relpath(p, dist.location) for p in paths]
-
-            if dist.has_metadata('METADATA'):
-                metadata = dist.get_metadata('METADATA')
-        else:
-            # Otherwise use pip's log for .egg-info's
-            if dist.has_metadata('installed-files.txt'):
-                paths = dist.get_metadata_lines('installed-files.txt')
-                paths = [os.path.join(dist.egg_info, p) for p in paths]
-                file_list = [os.path.relpath(p, dist.location) for p in paths]
-
-            if dist.has_metadata('PKG-INFO'):
-                metadata = dist.get_metadata('PKG-INFO')
-
-        if dist.has_metadata('entry_points.txt'):
-            entry_points = dist.get_metadata_lines('entry_points.txt')
-            package['entry_points'] = entry_points
-
-        if dist.has_metadata('INSTALLER'):
-            for line in dist.get_metadata_lines('INSTALLER'):
-                if line.strip():
-                    package['installer'] = line.strip()
-                    break
-
-        # @todo: Should pkg_resources.Distribution have a
-        # `get_pkg_info` method?
-        feed_parser = FeedParser()
-        feed_parser.feed(metadata)
-        pkg_info_dict = feed_parser.close()
-        for key in ('metadata-version', 'summary',
-                    'home-page', 'author', 'author-email', 'license'):
-            package[key] = pkg_info_dict.get(key)
-
-        # It looks like FeedParser cannot deal with repeated headers
-        classifiers = []
-        for line in metadata.splitlines():
-            if line.startswith('Classifier: '):
-                classifiers.append(line[len('Classifier: '):])
-        package['classifiers'] = classifiers
-
-        if file_list:
-            package['files'] = sorted(file_list)
+
+        for key in ('Summary', 'Home-page', 'Author', 'Author-email', 'License'):
+            package[key] = dist.metadata[key]
+
+        try:
+            entry_points_text = dist.read_text('entry_points.txt')
+            package['entry_points'] = entry_points_text.splitlines(keepends=False)
+        except FileNotFoundError:
+            pass
+        if dist.installer:
+            package['installer'] = dist.installer
+
+        file_iterator = (
+            _files_from_record(dist) or
+            _files_from_installed_files(dist.read_text('installed-files.txt'))
+        )
+        if file_iterator:
+            package['files'] = sorted(file_iterator)
+
         yield package
 
 

src/pip/_internal/metadata/pkg_resources.py

@@ -68,6 +68,8 @@ def in_usersite(self) -> bool:
         return misc.dist_in_usersite(self._dist)
 
     def read_text(self, name: str) -> str:
+        if not self._dist.has_metadata(name):
+            raise FileNotFoundError(name)
         return self._dist.get_metadata(name)
 
     def iter_entry_points(self) -> Iterable[BaseEntryPoint]: