"Unapproved" Comments are Visible

Hi,

This should be a cache issue. Please disable all kinds of cache systems and check again. 

Hi. Disabling any and all caches on a live service to detect a transient issue isn't feasible on our infrastructure.
Instead here is possibly the source of the issue:
in /utils/class.WpdiscuzHelper.php :

    public function isUnapprovedInTree($comments) {
        foreach ($comments as $comment) {
            if ($comment->comment_approved === "0") {
                return true;
            }
            if ($children = $comment->get_children()) {
                return $this->isUnapprovedInTree($children);
            }
        }

        return false;
    }

This function is used to determine if comments are cacheable but contains a logic mistake, where if an "approved branch" is read first, the function skips the rest of the tree returning false.

one way to fix this issue in the code would be:

    public function isUnapprovedInTree($comments) {
        foreach ($comments as $comment) {
            if ($comment->comment_approved === "0") {
                return true;
            }
            if ($children = $comment->get_children()) {
                if($this->isUnapprovedInTree($children)){
                    return true;
                }
            }
        }

        return false;
    }

the difference being: if an unapproved leaf is found, we can say for sure the whole contains unapproved comment, but otherwise we still need to check the rest of the tree.

i could not reproduce it, but here is the next best thing i found:

cd [path-wpdiscuz-cache]/cache/comments/ && grep -ari 's:16:"comment_approved";s:1:"0";'

returning elements, ie unapproved comment in the cache maintained by wpdiscuz.
As a last note: this might not be the only source of this peculiar issue, just the one i found.

@gelaw, Thank you very much for this detailed and careful analysis of the problem.

@asti, I hope WPDiscuz takes advantage of this assistance from @gelaw and is able to update the plugin and fix the problem. Let us know if that's going to happen. Thanks.