Variable name Bug analysis of a piece of code to obtain the variable name of a variable in PHP

Copy the code The code is as follows:

/**
* Get variable name
*
* @param $string
* @return $string
*
* $test = "helo";
* $test2 = "helo";
* getVarName($test2);
*/
function getVarName(&$src){
//Storage the current variable value
$save = $src;
//Storage all variables Value
$allvar = $GLOBALS;
//Do not traverse $GLOBALS directly in the function, stack problems will occur
foreach($allvar as $k=>$v){
//The variable values ​​are the same, but they may not be the same Variable, because the values ​​of multiple variables may be the same
if ($src == $v){
//Change the value of the current variable $src
$src = 'change';
//If $GLOBALS[$k] also As it changes, it's the same variable.
if ($src == $GLOBALS[$k]){
//echo "$$k name is $k
";
//Restore variable value
$src = $save;
return $k;
}
}
}
}

After copying it, I found that the test results are sometimes correct and sometimes wrong. After thinking about it for a long time, I finally figured it out. Although it is very simple, I still recorded it. I hope that students who encounter the same situation will pay attention. .
For example: Now I test

Copy the code The code is as follows:

$test2 = "hello";
$countNum=0;
echo getVarName($test2);
//Logically the output should be " test2", but the output is "countNum",

because there is a problem with
if ($src == $v) in the function, such as $src="hello", there is a variable $countNUm=0 in $GLOBALS;
At this time, if ($src == $v) is judged during the loop, that is, "hello" == 0, the comparison result is true. During type conversion, "hello" is converted into an integer and is 0,
Then exit the loop , and got wrong results.
One solution is to change if ($src == $v) to if ($src===$v), which is identical.
If I understand it wrong, you are welcome to correct me and let us make progress together.

The above introduces the bug analysis of a piece of code for obtaining the variable name of a variable in PHP, including the variable name. I hope it will be helpful to friends who are interested in PHP tutorials.