Custom error message for all rules

Hi there!
I was looking for a way to use a single error message in the validation class for all rules. I managed to do it with few changes in system/Validation/Validation.php

The following lines in function setRules can be modified like this:

 -- Original -- 

PHP Code:

                if (array_key_exists('errors', $rule)) {
                    $this->customErrors[$field] = $rule['errors'];
                    unset($rule['errors']);
                } 


-- Modified --

PHP Code:

                if (array_key_exists('errors', $rule) && is_array($rule['errors'])) {
                    $this->customErrors[$field] = $rule['errors'];
                    unset($rule['errors']);
                } elseif(array_key_exists('error', $rule) && is_string($rule['error'])) {
                    $this->customErrors[$field] = $rule['error'];
                    unset($rule['error']);
                } 


And also function getErrorMessage:

-- Original --

PHP Code:

        // Check if custom message has been defined by user
        if (isset($this->customErrors[$field][$rule])) {
            $message = lang($this->customErrors[$field][$rule]);
        } elseif (null !== $originalField && isset($this->customErrors[$originalField][$rule])) {
            $message = lang($this->customErrors[$originalField][$rule]);
        } else {
            // Try to grab a localized version of the message...
            // lang() will return the rule name back if not found,
            // so there will always be a string being returned.
            $message = lang('Validation.' . $rule);
        } 


-- Modified --

PHP Code:

        // Check if custom message has been defined by user
        if (isset($this->customErrors[$field][$rule])) {
            $message = lang($this->customErrors[$field][$rule]);
        } elseif (null !== $originalField && isset($this->customErrors[$originalField][$rule])) {
            $message = lang($this->customErrors[$originalField][$rule]);
        } elseif(is_string($this->customErrors[$field])) { 
            $message = $this->customErrors[$field];
        } else {
            // Try to grab a localized version of the message...
            // lang() will return the rule name back if not found,
            // so there will always be a string being returned.
            $message = lang('Validation.' . $rule).'kur';
        } 


I hope you will find this useful and this future find its way to the official release.

The official way to get this considered is to submit a PR in GitHub.