Added a news entry and some documentation about --force-keyring

docs/html/topics/authentication.md

@@ -74,6 +74,23 @@ $ echo "your-password" | keyring set pypi.company.com your-username
 $ pip install your-package --index-url https://pypi.company.com/
 ```
 
+Pip is conservative and does not query keyring at all when `--no-input` is used
+because the keyring might require user interaction such as prompting the user
+on the console. You can force keyring usage by passing `--force-keyring` or one
+of the following:
+
+```bash
+# possibly with --user, --global or --site
+$ pip config set global.keyring-does-not-prompt true
+# or
+$ export PIP_KEYRING_DOES_NOT_PROMPT=1
+```
+
+Be careful when doing this since it could cause tools such as Pipx and Pipenv
+to appear to hang. They show their own progress indicator while hiding output
+from the subprocess in which they run Pip. You won't know whether the keyring
+backend is waiting the user input or not in such situations.
+
 Note that `keyring` (the Python package) needs to be installed separately from
 pip. This can create a bootstrapping issue if you need the credentials stored in
 the keyring to download and install keyring.

news/11020.feature.rst

@@ -0,0 +1 @@
+Add ``--force-keyring`` flag which allows ``keyring`` lookups in combination with ``--no-input``. See the Authentication page in the documentation for more info.