修复遗留代码而不破坏所有内容

I have some code like this :

somefunc($row['some_key']);

Sometimes, $row might not have 'some_key' which logs an Undefined index warning.

How do you fix this warning without changing the current behavior of the program ?

I know I need to fix the problem to the source but this is a legacy codebase T_T

My attemp

if(!isset($row['some_key'])){
    somefunc(null);
}
else{
    somefunc($row['some_key']);
}

Is this equivalent ?

Sure, it is equivalent, but you can be more terse (if you're interested) with a ternary operator (http://www.php.net/manual/en/language.operators.comparison.php you have to scroll a little, unfortunate, they don't have any anchor for it)...

somefunc( (isset($row['some_key'])) ? $row['some_key'] : null );

If you don't want to change the structure of the entire program, I would suggest adding a simple isset() check before accessing any variable that throws an Undefined index/offset error.

if (isset($row['some_key'])) {
    somefunc($row['some_key']);
}

This way, the function will get called if and only if the some_key index exists. You could shorten it further using a ternary expression, but it would not be very readable, so I suggest using if-else blocks instead.

You can also do like this:

somefunc( isset($row['some_key']) ? $row['some_key'] : null)