Unable to install

This happen if commerce checkout module is not ready during installation of commerce email.
I get the same error if i try to install this module as a dependency of another module.

If i install only this module and commerce checkout is already installed i have no problems.

Same issue when combined with other modules (dependencies) to be enabled:

The following extensions will be enabled: commerce_invoice_email, htmlmail, variable_email, commerce_email
Do you really want to continue? (y/n): y
Drush command terminated abnormally due to an unrecoverable error. [error]
Error: Call to undefined method stdClass::save() in
/var/www/vhosts/******************/httpdocs_**/sites/all/modules/commerce_email/commerce_email.install,line 12

Line 12 is the last line of this function:
function commerce_email_enable() {

 // Make sure the rules created by commerce have been taken into account
  drupal_flush_all_caches();
  // Deactivate default commerce rules to send order email
  $rules_config = rules_config_load('commerce_checkout_order_email');
  $rules_config->active = FALSE;
  <strong>$rules_config->save();</strong>

However, visiting the module page, enabling and saving and then there is no error. Sounds suspiciously similar to this historic issue: https://drupal.org/node/1651034 ?

No time to dig just now (entity/empty or rule naming issue?), but may have a chance to investigate further at some point - and certainly happy to test any patches etc. I can see that this module is not being heavily maintained (and looking for co-maintainer), so expect to DIY :)

I've created a basic patch which validates the rules before it tries to set it inactive on enable or disable. Please review

Previous patch failed to apply so providing new one for 2.x-dev version.

Patch #4 works perfectly!

Patch #4 also worked for me. Thanks a lot!

Patch #4 works. Thanks!

#4 worked for me as well, thank you!

Reviewing now.

Had to use patch but got it to apply. Normally would use a !empty() check on a string, but oh well ... committing as is.