TYPO3 Core

Steps to reproduce:

- Add content/plugins with pagereferences
- Set for each reference to a page way up in the parent-lineage
- Go to workspace-module, select "Draft"

Expected behavior:

Display changes on this and sub-levels

Actual behavior:

Grows large stack (>1GB) and eventually dies of memory-limitations on a moderate site with ~40 pages. Server-log indicates segfault, debugger shows stack-overflow caused by near-infinite loop.

It might be possible that this happens, however to reproduce that some more details would be interesting on your TCA configuration that is required to produce this endless-loop.

Is the plugin you referred to using FlexForms to define the page-loop?
If that's the case, https://review.typo3.org/#/c/37891/ might be the root of this endless-loop... that patch extends the handling for FlexForms but only is checking the type of the XML container, not the accordant sub-fields...

I have experienced the same problem. I tried to create an example as small as possible which causes the error. Here is what I got:

I have a plugin, containing a flexform in which you can enter a page list. Flexform is like this:

<T3DataStructure>
  <meta>
    <langDisable>1</langDisable>
  </meta>
 <sheets>
  <sDEF>
   <ROOT>
     <TCEforms>
      <sheetTitle>Foobar</sheetTitle>
     </TCEforms>
     <type>array</type>
     <el>
      <settings.pageList>
        <TCEforms>
          <label>Baz</label>
          <config>
            <type>group</type>
            <internal_type>db</internal_type>
            <allowed>pages</allowed>
            <size>10</size>
            <maxitems>100</maxitems>
            <minitems>0</minitems>
          </config>
        </TCEforms>
      </settings.pageList>
     </el>
   </ROOT>
  </sDEF>
 </sheets>
</T3DataStructure>

I have two pages A and B. On page A I use the plugin and the page list inside the plugin only contains B.
On page B I have a reference to the content element (so the plugin) on page A.

When I now create workspace versions of A, B and the content element/plugin on page A, then I get the dependency loop while looking at either page A or B with the workspace module in the backend.

I am not sure if there are smaller examples for the problem. The machine I analysed is kind of a huge thing and this is just the smallest example I could extract from it.

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/46988

Patch set 1 for branch TYPO3_6-2 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/46991

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/46992

Patch set 3 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/46988

Patch set 4 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/46988

Patch set 5 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/46988

Behavior is caused by #65126 - WIP of a fix has been started in #70921

IMHO this issue isn't only caused by #65126, this can also happen if you have circular dependencies, which will be resolved by this patch.

I agree, the patch on #65126 does not solve this problem.
I just had another issue with circular dependencies in latest TYPO3 6.2: An FCE had a link to the page where it was placed on.

The problem persists and I think there are a couple of ways to produce such a dependency loop.