Simpletest now fails with max_allowed_packet = 1M

tested. Prevents the WSOD from adding more test classes. Tests still run as expected.

As one of the people who experienced this problem I'm glad for this patch. Like pwolanain I tested and verified it works as expected.

@Damien Tournoud thanks for the fix.

I think we should make the code comments better still. We don't explain why we call batch_process().

@Dries - did you look at the comments in #2?

Yes, I don't think they are sufficiently explanatory. In fact, I think the comments in #1 were more specific. Let's take another pass at the comments! :)

ok, here's another try.

I'm still not sure I understand this patch, and the code comments still don't help me. Sorry. I'll have to start digging the code first so I fully understand this before I can review this properly. Until then, this is a bit fishy.

@Dries - MAMP, xampp, and other setups come with mysql configured to max_allowed_packet = 1M. The simpletest form ($form) has reached a point where it is really really large. Normally, when batch_set() is called in a form submit handler (in this case simpletest_test_form_submit() through simpletest_run_tests()) drupal_process_form() makes sure batch_process() is called. But, before drupal_process_form() executes batch_process() it adds the entire form array to the batch that is stored in the database. In this case the form that is stored in the database causes the $batch to be larger then 1M so an exception is thrown and execution is stopped.

By adding batch_process() in simpletest_run_tests() we set the batch processing into motion without the full simpletest form being added the batch so the form is not stored in the database.

It is a special case for the simpletest form because it is so large.

Does this explanation help?

We should avoid mysql specific references. This problem could come up in a different database engine. Can this be rephrased in more general terms.

+  // Normally, the forms portion of the batch API takes care of calling
+  // batch_process(), but in the process it saves the whole $form into the
+  // database (which is huge for the test selection form).
+  // By calling batch_process() directly, we skip that behavior and ensure
+  // that we don't exceed the size of data that can be sent to the database
+  // (max_allowed_packet on MySQL).

The last line refers to mysql and a mysql setting. That's not general.

I did some checking. Of the major databases (mysql, postgresql, oracle, mssql) my understanding is that this will only affect mysql.

Thanks for clarifying. That helps. I committed the patch to CVS HEAD. Thanks.