Tell us what should happen
Get a 404 error
groovy-ant is a dependency by default. Since you made it provided, it won't be included in your war file. Are you making the library available by installing it into your Tomcat ahead of time?
Never mind my last comment. I think I misunderstood the original description. Sorry for the noise.
I have confirmed this behavior locally. The app at https://github.com/grails-samples/music has been upgraded to 3.2.0 and does have the groovy-ant dependency at https://github.com/grails-samples/music/blob/329b160108b51ebef6abbd6f55dab70149edb15b/build.gradle#L45.
When I deploy the app to Tomcat 8.5.5 something is wrong with the deployment and the app will not respond. When I remove the groovy-ant dependency and redeploy, things appear to work as expected.
This is likely relevant:
$ diff noant.txt ant.txt
< 4550894 08-03-16 13:52 WEB-INF/lib/groovy-2.4.7.jar
< 215463 08-03-16 13:52 WEB-INF/lib/groovy-xml-2.4.7.jar
< 97862 08-03-16 13:52 WEB-INF/lib/groovy-templates-2.4.7.jar
> 69674 06-03-16 18:50 WEB-INF/lib-provided/groovy-ant-2.4.7.jar
> 2019274 04-29-14 23:14 WEB-INF/lib-provided/ant-1.9.4.jar
> 11612 04-29-14 23:01 WEB-INF/lib-provided/ant-antlr-1.9.4.jar
> 4550894 06-03-16 18:50 WEB-INF/lib-provided/groovy-2.4.7.jar
> 18381 04-29-14 23:01 WEB-INF/lib-provided/ant-launcher-1.9.4.jar
> 135183 06-03-16 18:50 WEB-INF/lib-provided/groovy-groovydoc-2.4.7.jar
> 117783 04-29-14 23:01 WEB-INF/lib-provided/ant-junit-1.9.4.jar
> 97862 06-03-16 18:50 WEB-INF/lib-provided/groovy-templates-2.4.7.jar
> 215463 06-03-16 18:50 WEB-INF/lib-provided/groovy-xml-2.4.7.jar
noant.txt is the listing of the all of the .jar files in the .war file when the provided "org.codehaus.groovy:groovy-ant" dependency is not in build.gradle. ant.txt is the listing of all of the .jar files in the .war file when the groovy-ant dependency is in build.gradle. Notice that groovy-2.4.7.jar is not in WEB-INF/lib/ when the provided groovy-ant dependency is present. groovy-2.4.7 is in WEB-INF/lib-provided/, which I think is only used by the embedded Tomcat, not when deploying to a real Tomcat.
add groovy-ant as a provided dependency to fix reloading of messages
One way to deal with this is to replace provided "org.codehaus.groovy:groovy-ant" with something like this:
exclude module: 'groovy'
exclude module: 'groovy-xml'
exclude module: 'groovy-templates'
Another option is to remove the groovy-ant dependency altogether. The consequence of that would be that i18n message reloading won't work in the development environment.
We will have a real solution for 3.2.1 but the above options should fix the deployment problem for 3.2.0.
Another option is to turn the groovy-ant dependency into a runtime dependency. The consequence of that is that there will be several jar files in the generated .war that aren't actually needed at runtime.
Partial fix for #10196 - Remove dependency on groovy-ant for reloadin…
…g of messages.properties
Remove groovy-ant dependency. Fixes grails/grails-core#10196
The dependency can be safely removed because reloading of message bundles no longer depends on Ant grails/grails-core@312bcdf
remove groovy-ant dependency
This is related to grails/grails-core#10196. For now, reloading of
i18n messages in the development environment will not work. Grails
3.2.1 contains a fix that supports message reloading and does not rely