[#596] update documentation: show maven example that fails the build …

…on error

Closes #596

RELEASE-NOTES.md

@@ -3,6 +3,10 @@
 # <a name="3.9.1"></a> Picocli 3.9.1 (UNRELEASED)
 The picocli community is pleased to announce picocli 3.9.1.
 
+The `picocli.AutoComplete` application no longer calls `System.exit()` unless requested by setting system property `picocli.autocomplete.systemExitOnError` or `picocli.autocomplete.systemExitOnSuccess` to any value other than `false`. Applications that rely on the exit codes introduced in picocli 3.9.0 need to set these system properties.
+
+This release adds support for quoted map keys with embedded '=' characters.
+
 This release contains bugfixes and enhancements.
 
 This is the forty-sixth public release.
@@ -27,6 +31,9 @@ Picocli follows [semantic versioning](http://semver.org/).
 No features were deprecated in this release.
 
 ## <a name="3.9.1-breaking-changes"></a> Potential breaking changes
+The `picocli.AutoComplete` application no longer calls `System.exit()` unless requested by setting system property `picocli.autocomplete.systemExitOnError` or `picocli.autocomplete.systemExitOnSuccess` to any value other than `false`.
+Applications that rely on the exit codes introduced in picocli 3.9.0 need to set these system properties.
+
 The new support for quoted map keys with embedded '=' characters [#594] may inpact some existing applications.
 If `CommandLine::setTrimQuotes()` is set to `true`, quotes are now removed from map keys and map values. This did not use to be the case.
 

docs/autocomplete.adoc

@@ -335,6 +335,8 @@ It may be useful to generate your completion scripts automatically during the bu
 Below is an example Maven snippet that demonstrates how to achieve this.
 
 === Maven Example
+TIP: Setting system property `picocli.autocomplete.systemExitOnError` ensures the build fails if there is any problem generating the completion script (requires picocli v3.9.1).
+
 [source,xml]
 ----
 <plugin>
@@ -346,19 +348,23 @@ Below is an example Maven snippet that demonstrates how to achieve this.
  <id>generate-autocompletion-script</id>
  <phase>package</phase>
  <goals>
- <goal>java</goal>
+ <goal>exec</goal>
  </goals>
- <configuration>
- <mainClass>picocli.AutoComplete</mainClass>
- <arguments>
- <argument>--force</argument><!-- overwrite if exists -->
- <argument>--completionScript</argument>
- <argument>${project.build.directory}/mycommand_completion.sh</argument>
- <argument>com.mycompany.mypackage.MyCommand</argument><!-- replace with your class -->
- </arguments>
- </configuration>
  </execution>
  </executions>
+ <configuration>
+ <executable>java</executable>
+ <arguments>
+ <argument>-Dpicocli.autocomplete.systemExitOnError</argument>
+ <argument>-cp</argument>
+ <classpath/>
+ <argument>picocli.AutoComplete</argument>
+ <argument>--force</argument><!-- overwrite if exists -->
+ <argument>--completionScript</argument>
+ <argument>${project.build.directory}/mycommand_completion.sh</argument>
+ <argument>mypackage.MyCommand</argument><!-- replace with your class -->
+ </arguments>
+ </configuration>
 </plugin>
 ----