warning: Invalid argument supplied for foreach() in /.../modules/node.module on line 376

I assumed that if the line numbers differed by a couple of lines, it was because it was a different version of drupal 4.7.

I am very sick now, so I don't have much time to check now if these issues are similar but I am 95% sure they are.

I did as you suggested, I had a fresh install and enabled the contributed modules one by one.

The problem was with one of my own modules.

I was calling node_load() with an undefined argument. This was called whenever there was a user picture on the page. In details, here is what was happening :

1. When there is a user picture on the page, the hook function hook_file_download() is called for all modules, because these pictures are uploaded using the upload module.
2. In my module, I was using that hook function, and in it I was invoking node_load to find the node to which the downloaded file was attached - forgetting that downloaded files are not always attached to nodes.

This being said, I think that this function is not well-written :

function node_load($param = array(), $revision = NULL, $reset = NULL) {

It accepts that there are no arguments sent, but can't deal with an empty $param array.

In the cases where node_load is called with an undefined argument, a more meaningful error message should be set. Or, alternatively, this should be added at the beginning of the function :

 if(empty($param)) {
 	//drupal_set_message(t('You have called node_load with $param undefined'));
	return false;
}

By adding this code, with the comment uncommented, I was able to see what was going on.

Imagine that, webchick, I was getting these errors whenever I was on OR leaving a page with a user picture on it. It didn't occur to me that it was a user picture causing this, it seemed random to me. LOL..

Actually, there shouldn't be a message set, imo. Just a return false. That message I used only for debug reasons. I really am a newbie with Drupal, and don't know how to debug it. The way that function is defined, it should handle being called with an undefined argument. If the argument is undefined, then the function should no nothing. It'd be good to return false, just to known that no node was loaded, of couse. As it is, with an undefined argument, the function does 'free games'.

I should have copied and pasted.

The code I used to catch my own error was :

  if(!isset($param)) {
    drupal_set_message(t('You have called node_load with $param undefined'));
    return false;
  }

No "empty" function used here.

node.module declares the function node_load like this :

function node_load($param = array(), $revision = NULL, $reset = NULL) {

The function can take as first argument either a single value (the nid) or an array of node info. As the comment says : @param $param : Either the nid of the node or an array of conditions to match against in the database query . The function does a first check : is $param a numeric value ? Then it's an nid. If not, the function assumes it's an array.

If node_load is called with no argument, that is, someone write node_load(), then the function gets an empty array as default argument. It can't get any node, because there are no conditions.

Now if someone makes a mistake and call that function with an undefined argument (as I did), then the only improvement that can be made to that function is to include the code above. I am not sure it's a great idea though. It is actually a mistake on the part of the caller.

If Drupal functions were all checking for validity of arguments passed, then I guess a lot of Drupal code would need to be modified. It's like the php compliant stuff : it would require a lot of work. :)

Best regards,

Caro
http://www.11heavens.com