Auth::guard('jwt')->id() returns string instead of integer for sub claim.

[Kim-Munbeom]

네, 요청하신 틀에 맞춰 php-open-source-saver/jwt-auth 패키지에서 $\text{ID}$가 $\text{string}$으로 반환되는 문제를 보고하는 $\text{GitHub}$ 이슈를 작성해 드립니다.

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Subject of the issue

Auth::guard('jwt')->id() returns $\text{string}$ instead of $\text{integer}$ for $\text{sub}$ claim.

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Your environment:

Q	A
Bug?	yes
New Feature?	no
Framework	Laravel
Framework version	11.46.0
Package version	2.8.2
PHP version	8.3.26

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Steps to reproduce

1. Ensure your database primary key for the users table is an $\text{INTEGER}$ (standard Laravel setup).
2. Log in a user to generate a $\text{JWT}$.
3. Access the authenticated user's $\text{ID}$ using the $\text{jwt}$ guard.

$user_id = Auth::guard('jwt')->id();

// Or using the helper function
$user_id_helper = auth('jwt')->id();

4. Check the data type of the returned $\text{ID}$.

// Check the type of the returned ID
dd([
    'ID from auth()->id()' => auth()->id(),
    'ID from auth(\'jwt\')->id()' => auth('jwt')->id(),
    'Type of JWT ID' => gettype(auth('jwt')->id()),
    'ID from Auth::id()' => Auth::id(),
    'ID from Auth::guard(\'jwt\')->id()' => Auth::guard('jwt')->id(),
    'Type of JWT Guard ID' => gettype(Auth::guard('jwt')->id()),
]);

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Expected behaviour

The $\text{ID}$ returned by $\text{Auth::guard('jwt')->id()}$ should match the data type of the user's primary key in the database, which is typically $\text{integer}$.

Expected output for type check:

...
'Type of JWT ID' => 'integer',
'Type of JWT Guard ID' => 'integer',

(assuming the default guard returns $\text{integer}$)

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Actual behaviour

The $\text{ID}$ is returned as a $\text{string}$ (likely due to the $\text{sub}$ claim being read as a string from the $\text{JWT}$ payload), even when the database primary key is an $\text{integer}$.

Actual output from the $\text{dd()}$ in steps to reproduce:

array:6 [
  "ID from auth()->id()" => 1779851
  "ID from auth('jwt')->id()" => "1779851"
  "Type of JWT ID" => "string" // <-- ISSUE
  "ID from Auth::id()" => 1779851
  "ID from Auth::guard('jwt')->id()" => "1779851"
  "Type of JWT Guard ID" => "string" // <-- ISSUE
]

This requires explicit type casting ((int)) in application code when comparing the $\text{JWT}$ $\text{ID}$ to other $\text{integer}$ $\text{IDs}$, which can lead to subtle bugs.