Provide structured JSON output for pip index versions

src/pip/_internal/commands/index.py

@@ -8,11 +8,13 @@
 from pip._internal.cli import cmdoptions
 from pip._internal.cli.req_command import IndexGroupCommand
 from pip._internal.cli.status_codes import ERROR, SUCCESS
-from pip._internal.commands.search import print_dist_installation_info
+from pip._internal.commands.search import (
+    get_installed_distribution,
+    print_dist_installation_info_if_exists,
+)
 from pip._internal.exceptions import CommandError, DistributionNotFound, PipError
 from pip._internal.index.collector import LinkCollector
 from pip._internal.index.package_finder import PackageFinder
-from pip._internal.metadata import get_default_environment
 from pip._internal.models.selection_prefs import SelectionPreferences
 from pip._internal.models.target_python import TargetPython
 from pip._internal.network.session import PipSession
@@ -137,9 +139,9 @@ def get_available_package_versions(self, options: Values, args: List[Any]) -> No
             formatted_versions = [str(ver) for ver in sorted(versions, reverse=True)]
             latest = formatted_versions[0]
 
+        dist = get_installed_distribution(query)
+
         if options.json:
-            env = get_default_environment()
-            dist = env.get_distribution(query)
             structured_output = {
                 "name": query,
                 "versions": formatted_versions,
@@ -154,4 +156,4 @@ def get_available_package_versions(self, options: Values, args: List[Any]) -> No
         else:
             write_output(f"{query} ({latest})")
             write_output("Available versions: {}".format(", ".join(formatted_versions)))
-            print_dist_installation_info(query, latest)
+            print_dist_installation_info_if_exists(latest, dist)

src/pip/_internal/commands/search.py

@@ -14,6 +14,7 @@
 from pip._internal.cli.status_codes import NO_MATCHES_FOUND, SUCCESS
 from pip._internal.exceptions import CommandError
 from pip._internal.metadata import get_default_environment
+from pip._internal.metadata.base import BaseDistribution
 from pip._internal.models.index import PyPI
 from pip._internal.network.xmlrpc import PipXmlrpcTransport
 from pip._internal.utils.logging import indent_log
@@ -111,9 +112,9 @@ def transform_hits(hits: List[Dict[str, str]]) -> List["TransformedHit"]:
     return list(packages.values())
 
 
-def print_dist_installation_info(name: str, latest: str) -> None:
-    env = get_default_environment()
-    dist = env.get_distribution(name)
+def print_dist_installation_info_if_exists(
+    latest: str, dist: Optional[BaseDistribution]
+) -> None:
     if dist is not None:
         with indent_log():
             if dist.version == latest:
@@ -130,6 +131,11 @@ def print_dist_installation_info(name: str, latest: str) -> None:
                     write_output("LATEST:    %s", latest)
 
 
+def get_installed_distribution(name: str) -> Optional[BaseDistribution]:
+    env = get_default_environment()
+    return env.get_distribution(name)
+
+
 def print_results(
     hits: List["TransformedHit"],
     name_column_width: Optional[int] = None,
@@ -163,7 +169,8 @@ def print_results(
         line = f"{name_latest:{name_column_width}} - {summary}"
         try:
             write_output(line)
-            print_dist_installation_info(name, latest)
+            dist = get_installed_distribution(name)
+            print_dist_installation_info_if_exists(latest, dist)
         except UnicodeEncodeError:
             pass