1. The missing echo
2. The echo too much
3. Rules for numbers
4. Rules for enums
5. Rules for foreign keys
6. Ending ?> tag in non-view

Please join the party by adding your own favorite Yii programming errors. Be sure to leave at least a hint at the correction.

The missing echo ¶

In the view put:

<h1>Edit item: <?php $model->label; ?></h1>

Now spend your time debugging why $model->label has no value set.

The echo too much ¶

In the view put:

<h1>Edit item: <?php echo $this->widget('CWidget'); ?></h1>

"Object of class CWidget could not be converted to string." A widget may not have an echo.

Rules for numbers ¶

In the model rules() method put:

array('count', 'number', 'integerOnly'=>true),

then try

array('count', 'numeric', 'integerOnly'=>true),

and only then look it up: 'numerical'.

Rules for enums ¶

In the model rules() method put:

array('format', 'range', 'in' => array('html', 'rss2', 'atom', 'json', 'xml')),

then later remind yourself that Yii is not SQL.

Rules for foreign keys ¶

In the model rules() method put:

array('foreingKey', 'exists', 'className' => 'SomeModel', 'attributeName' => 'id'),

Sure we have 'exists' method for CActiveRecord model, but ...

Ending ?> tag in non-view ¶

Extend a base class or edit a config file (needs to be included before the sessions starts) and leave a ?> at the ending with at least one trailing white space character. Make sure output buffering is off. Cry manly tears while trying to figure out why "Cannot modify header information - headers already sent" spams your log files.