Backtrace is hidden when 'show all messages' is selected

In D6 the admin form for setting 'error_level' is defined as:'#options' => array(t('Write errors to the log'), t('Write errors to the log and to the screen'))
so error_level = 0 for writing errors just to the log, and error_level = 1 for writing to the log and screen.

In D7 the settings are done by constants:

    '#options' => array(
      ERROR_REPORTING_HIDE => t('None'),
      ERROR_REPORTING_DISPLAY_SOME => t('Errors and warnings'),
      ERROR_REPORTING_DISPLAY_ALL => t('All messages'),
    ),

which have the values 0, 1 and 2.

In the D6 version of backtrace_error_handler() we test for error_level == 1 when determining whether to display the backtrace. This is fine, but in D7 the same code is used, which means we only get the backtrace when the option 'Errors and Warnings' is selected, and it is not displayed for the more comprehensive option 'All messages'.

Therefore I suggest the test in D7 is changed from

    if (variable_get('error_level', 1) == 1) {

to

    if (variable_get('error_level', 1) != ERROR_REPORTING_HIDE) {

If others agree to the change I will make a patch, but I might wait for #1163356: New error handling option: Backtrace and normal message because whichever is committed first, then the other patch will need to be re-rolled.

Jonathan