Division by zero

This is a duplicate of #352046: Division by zero; see there for any informations.

The code should simply be

  if ($maxcomments > 1) {

Mine is failing in sites/all/modules/xmlsitemap/xmlsitemap/xmlsitemap.module on line 313

function xmlsitemap_chunk_count($reset = FALSE) {
  static $chunk_count;
  if (!isset($chunk_count) || $reset) {
    $chunk_size = variable_get('xmlsitemap_chunk_size', 1000);
    $chunks_info = variable_get('xmlsitemap_sitemap_chunks_info', array());
    $link_count = 0;
    $module_count = 0;
    foreach(module_implements('xmlsitemap_link_count') as $module) {
      if (!isset($chunks_info[$module]['id'])) {
        $chunks_info[$module]['id'] = substr(md5($module), 0, 8);
      }
      $result = module_invoke($module, 'xmlsitemap_link_count');
      $count = empty($result) ? 0 : $result;
      if (!isset($info['links']) && $info['links'] != $count) {
        $chunks_info[$module]['needs update'] = TRUE;
      }
      elseif (!isset($chunks_info[$module]['needs update'])) {
        $chunks_info[$module]['needs update'] = FALSE;
      }
      $chunks_info[$module]['links'] = $count;
      $link_count += $count;
      $module_count++;
    }
    $chunk_count = (integer) ($link_count / $chunk_size);
    // Adjust the chunk count because each module will not share its own
    // chunks with the other modules.
    $chunk_count += $module_count;
    if ($chunk_count > 1000) {
      $new_size = (integer) ceil($link_count / 100000) * 100;
      // Set which modules needs to update their cache files.
      foreach ($chunks_info as $module => $info) {
        if (!empty($info['links']) && $info['links'] > $old_size) {
          $chunks_info[$module]['needs update'] = TRUE;
        }
        elseif (!isset($chunks_info[$module]['needs update'])) {
          $chunks_info[$module]['needs update'] = FALSE;
        }
      }
      variable_set('xmlsitemap_chunk_size', $new_size);
      $chunk_size = $new_size;
    }
    $chunk_count = 0;
    foreach ($chunks_info as $module => $info) {
      // If a module is not enabled, its links will not be added to the
      // sitemap.
      if (!module_exists($module)) {
        $chunks_info[$module]['first chunk'] = -1;
      }
      else {
        $chunks_info[$module]['chunks'] = $chunks = ceil($info['links'] / $chunk_size);
        if ($chunks) {
          $chunks_info[$module]['first chunk'] = $chunk_count;
          $chunk_count += $chunks;
        }
        else {
          $chunks_info[$module]['first chunk'] = -1;
        }
      }
    }
    variable_set('xmlsitemap_sitemap_chunks_info', $chunks_info);
  }
  return $chunk_count;
}

It starts with:

    $chunk_count = (integer) ($link_count / $chunk_size);

So, why is the beta versions not alpha tested before released to be bug tested or is there something unique about my installation with no core changes?

@strikehawkecomm: Thanks for reporting this, I'll try and take a look at the versions code.

Line 313 is $chunk_count = (integer) ($link_count / $chunk_size);.

The variable $chunk_size comes directly from variable_get('xmlsitemap_chunk_size', 1000), but can also be set to a different value in some code just a little bit later:

      $new_size = (integer) ceil($link_count / 100000) * 100;
      ...
      variable_set('xmlsitemap_chunk_size', $new_size);
      $chunk_size = $new_size;

If $link_count is 0 (for instance when the modules are first installed), then $chunk_size is going to be set to 0, leading to a division by zero on the next time this code is executed.

If the attached patch looks good, I'll commit this later today.

The value for the chunk size is changed when the number of chunks is greater than 1000, which means that the number of links must be at least 1000001; in such case, $link_count is surely not 0.

The reported error is the division by zero, and who re-opened the issue pointed out that (integer) ($link_count / $chunk_size) is the line causing the error. If this is the case, then the division by zero is caused by $chunk_size being set to zero.

The code, as also reported by strikehawkecomm in #2, would change the value for the chunk size only when the numbers of chunks is greater than 1000, which means that $link_count must be at least 1000001. In these case, $new_size = (integer) ceil($link_count / 100000) * 100 would assign 1100 to $new_size. Changing the code from $new_size = (integer) ceil($link_count / 100000) * 100 to $new_size = (integer) ceil(max($link_count, 1) / 100000) * 100 doesn't change anything because max($link_count, 1), where $link_count is 1000001 will always use the value of $link_count.

To me, it seems that the error is caused by the fact the variable $chunk_size has a wrong value because the Drupal variable used to initialize it is set to 0 for some reasons; this is not necessarily caused by code executed in XML sitemap.

The code reported in the last comments doesn't even exist in the development snapshot, which uses different code.

The reported code doesn't exist anymore in the last commits done.
I would rather see this bug report as fixed.