grails form redirect gives 404, but url mapping works - forms

Question

I feel like I've entered the Twilight Zone. I have a Grails form that redirects to a URL, but gives a 404. If I go directly to that exact URL, everything works fine (that is, the URL mappings are correct).
This is an example generated form tag:
<form action="/alm/contactRefresh/itemRefreshProcess/7070" method="post">
On submit, it redirects to:
http://localhost:8080/alm/contactRefresh/itemRefreshProcess/7070
But gives this error:
HTTP ERROR 404
Problem accessing /alm/contactRefresh/itemRefreshProcess/7070. Reason:
NOT_FOUND
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But then if I just go directly to that same URL (by focusing the browser Location bar and pressing enter), the page renders just fine, though the form params are lost because it's just a GET now. I've also tried changing the form method to GET, and that doesn't work either (throws a 404).
I've done similar forms a zillion times before with no problems. I'm sure this is some stupid user error, but I seriously can't figure out what's wrong.
Thanks for any ideas!

Answer 1

So, I finally started ripping parts out of the form and found out that for some reason you can’t name a Grails checkbox starting with the word "action". It must be something related to the default params["action"] entry. Though my checkbox names were a concatenation of "action_" + an id.
Anyway, there was some kind pre-processing of the checkbox form params that was blowing up before making it to the controller, and somehow that translated to a 404 instead of an actual Exception.
Originally I had this:
<g:checkBox name="action_${serviceRefreshAction.id}" value="${true}" />
Which renders this:
<input type="hidden" name="_action_7196" /><input type="checkbox" name="action_7196" checked="checked" id="action_7196" />
I changed "action" to "myAction", like this:
<g:checkBox name="myAction_${serviceRefreshAction.id}" value="${true}" />
Which renders this:
<input type="hidden" name="_myAction_7206" /><input type="checkbox" name="myAction_7206" checked="checked" id="myAction_7206" />
And now everything works fine.
Five hours of my life down the drain.
But I guess I have to forgive Grails, for the all time it saves me on a daily basis normally. :o)