[TYPO3-mvc] Strange caching behaviour

[Jan Kornblum]

Hi newsgroup,

i've got an extbase plugin with several cached controller actions. The 
first action in ext_localconf.php is a list action. There is one page 
containing the plugin:

(1) /pluginpage.html

When calling the page above, the first controller action is executed 
and everything is fine. Also, when calling a show action with a correct 
cHash everything works as expected:

(2) 
/pluginpage.html?tx_ext[controller]=MyController&tx_ext[action]=show&tx_ext[myModel]=123&cHash=xyz

But now the TYPO3 page cache is cleared an the show action gets called 
again directly after it, but without having any cHash parameter:

(3) 
/pluginpage.html?tx_ext[controller]=MyController&tx_ext[action]=show&tx_ext[myModel]=123

Now calling (1) again after this, the page displays the plugins output 
of (3), the show action instead of the list action!? The result of (3) 
seems to have been cached for (1), because a cHash was missing when 
calling (3).

Is this a bug?

I'm aware that the caching mechanism can't work correctly when the 
cHash param is missing or incorrect but i'm sure that all the links are 
built correctly from inside my plugin (containing a cHash).

The problem is, that this scenario regularly happens to a live website 
and i don't know how to prevent it (as everybody in the www might just 
call (3) without any cHash param).

How can i prevent this behaviour?

Kind regards, Jan