Recently I had to recover the server from a backup after clearing the
/osgi/state, because I was getting "A JS module with the same
name already exists" exception when the server was restarted.
There are over 100 custom modules in my instance and it was unclear
which one is faulty. The issue was fatal as I couldn't even show the
login page.
Later I was able to detect the problematic module by tweaking the
relevant code, which now prints the given module details:
https://github.com/liferay/liferay-portal/blob/master/modules/apps/frontend-js/frontend-js-loader-modules-extender/src/main/java/com/liferay/frontend/js/loader/modules/extender/internal/npm/flat/FlatJSPackage.java
if (_jsModules.putIfAbsent(jsModule.getName(), jsModule) != null) {
throw new IllegalStateException(
"A JS module with the same name " + jsModule.getName() + " (" + getId() + ") already exists in " + _jsModules.get(jsModule.getName()).getJSPackage().getId());
}
It would be nice to have something like this directly in the LR code.
After removing that module (a JSP override containing a main.js file)
the server restarted successfully. Once that module was redeployed, no
similar exception was thrown anymore (it will be thrown next time the
/osgi/state/ is cleared).
