Try/catch 'Call to a member function query() on null' error-CodePudding

I have a SQL query ($query) that I create dynamically based on a users selections (I already perform sanitizing on user input so there is no issue of SQL injection). However sometimes the query returns a PHP Fatal error so I wanted to output all of the variables to a file so do some digging.

My code is:

try {
    $results = $db->query($query);
} catch (Exception $e) {
    $all_vars = get_defined_vars();
    file_put_contents('query_problems.txt',date('Y-m-d H:i:s') . print_r($all_vars, True),FILE_APPEND);
}

However I still receive an error

Uncaught Error: Call to a member function query() on null

and the line it points to is where I run $db->query($query).

What am I doing wrong? How do I catch this error?

CodePudding user response：

The problem is you're catching an Exception, not an Error (that is being throw). If you want to catch both (exceptions and errors), you should use Throwable.

try
{
   // Code that may throw an Exception or Error.
}
catch (Throwable $t)
{
   // Executed only in PHP 7, will not match in PHP 5
}

As it says in doc:

As the Error hierarchy does not inherit from Exception, code that uses catch (Exception $e) { ... } blocks to handle uncaught exceptions in PHP 5 will find that these Errors are not caught by these blocks. Either a catch (Error $e) { ... } block or a set_exception_handler() handler is required.