Improve documentation of commit validation
Mention that the plugin can reject commits by throwing an
exception.
Make it clearer that the validation also applies to commits made
within the Gerrit Web UI.
Change-Id: Ibd58aed5cd2a25ebe882020c7a530942c18dd8cd
diff --git a/Documentation/config-validation.txt b/Documentation/config-validation.txt
index ab5d04a..fd8c0bd 100644
--- a/Documentation/config-validation.txt
+++ b/Documentation/config-validation.txt
@@ -2,14 +2,18 @@
======================================
Gerrit supports link:dev-plugins.html[plugin-based] validation of
-uploaded commits.
+commits.
-This allows plugins to perform additional validation checks against
-uploaded commits, and send back a warning or error message to the git
-client.
+Plugins implementing the `CommitValidationListener` interface can
+perform additional validation checks against new commits.
-To make use of this feature, a plugin must implement the `CommitValidationListener`
-interface.
+If the commit fails the validation, the plugin can either provide a
+message that will be sent back to the git client, or throw an exception
+which will cause the commit to be rejected.
+
+Validation applies to both commits uploaded via `git push`, and new
+commits generated via Gerrit's Web UI features such as the rebase, revert
+and cherry-pick buttons.
Out of the box, Gerrit includes a plugin that checks the length of the
subject and body lines of commit messages on uploaded commits.
