Keep the guardian service within the PHP the plugin supports

`true` as a return type is PHP 8.2, but the plugin advertises 8.1, so the
family screen's two service calls fataled on the 8.1 test job while every
other job passed. They now return `?\WP_Error` — null on success — which
matches RegistrationGate::validate() and works on 8.1.

PHPStan was analysing against whatever PHP happened to be running (8.3 in
CI, newer locally), so `composer lint` was green on syntax the plugin
promises not to use. It is now pinned to the supported 8.1-8.3 range, which
reproduces this failure at lint time instead of three jobs later.

Co-Authored-By: Claude Opus 5 <[email protected]>

phpstan.neon

@@ -3,6 +3,13 @@ includes:
 
 parameters:
     level: 10
+    # Analyse against the whole supported range, not whatever PHP happens to be
+    # running. Without this, syntax newer than the `Requires PHP: 8.1` header
+    # promises passes lint on a modern local PHP and only fails in the 8.1 test
+    # job — which is how a PHP 8.2 `true` return type once reached CI.
+    phpVersion:
+        min: 80100
+        max: 80300
     paths:
         - src
     bootstrapFiles:

src/Guardian/FamilyPage.php

@@ -144,18 +144,18 @@ class FamilyPage {
 		// phpcs:ignore WordPress.Security.NonceVerification.Missing -- nonce checked by the caller.
 		$childId = absint( Val::int( $_POST['child_id'] ?? 0 ) );
 
-		$result = $this->guardians->updateChild( $guardianId, $childId, $this->postString( 'child_name' ), $this->postString( 'child_dob' ) );
+		$error = $this->guardians->updateChild( $guardianId, $childId, $this->postString( 'child_name' ), $this->postString( 'child_dob' ) );
 
-		return $result instanceof \WP_Error ? $result : self::RESULT_UPDATED;
+		return $error ?? self::RESULT_UPDATED;
 	}
 
 	private function handleRemove( int $guardianId ): string|\WP_Error {
 		// phpcs:ignore WordPress.Security.NonceVerification.Missing -- nonce checked by the caller.
 		$childId = absint( Val::int( $_POST['child_id'] ?? 0 ) );
 
-		$result = $this->guardians->removeChild( $guardianId, $childId );
+		$error = $this->guardians->removeChild( $guardianId, $childId );
 
-		return $result instanceof \WP_Error ? $result : self::RESULT_REMOVED;
+		return $error ?? self::RESULT_REMOVED;
 	}
 
 	/**

src/Guardian/GuardianService.php

@@ -99,8 +99,10 @@ class GuardianService {
 	 * Rename a child and update their date of birth. Refuses a student the caller
 	 * is not the guardian of, so the family screen cannot be turned into an
 	 * arbitrary user editor by posting someone else's id.
+	 *
+	 * Returns null on success, mirroring {@see \Unsupervised\Schedular\Registration\RegistrationGate::validate()}.
 	 */
-	public function updateChild( int $guardianId, int $studentId, string $name, string $dateOfBirth = '' ): true|\WP_Error {
+	public function updateChild( int $guardianId, int $studentId, string $name, string $dateOfBirth = '' ): ?\WP_Error {
 		if ( ! $this->guardians->isGuardianOf( $guardianId, $studentId ) ) {
 			return new \WP_Error( 'forbidden', __( 'That is not one of your children.', 'unsupervised-schedular' ) );
 		}
@@ -124,7 +126,7 @@ class GuardianService {
 
 		$this->setDateOfBirth( $studentId, $dateOfBirth );
 
-		return true;
+		return null;
 	}
 
 	/**
@@ -132,8 +134,10 @@ class GuardianService {
 	 * lesson or enrolment history: their id is referenced by lessons, payments and
 	 * credits, and deleting the user would orphan all of it. A studio admin
 	 * handles those cases by hand.
+	 *
+	 * Returns null on success.
 	 */
-	public function removeChild( int $guardianId, int $studentId ): true|\WP_Error {
+	public function removeChild( int $guardianId, int $studentId ): ?\WP_Error {
 		if ( ! $this->guardians->isGuardianOf( $guardianId, $studentId ) ) {
 			return new \WP_Error( 'forbidden', __( 'That is not one of your children.', 'unsupervised-schedular' ) );
 		}
@@ -148,7 +152,7 @@ class GuardianService {
 		$this->guardians->delete( $guardianId, $studentId );
 		$this->deleteUser( $studentId );
 
-		return true;
+		return null;
 	}
 
 	/**

tests/Unit/Guardian/FamilyPageTest.php

@@ -182,7 +182,7 @@ class FamilyPageTest extends TestCase
             'child_dob'        => '2015-04-02',
         ];
 
-        $this->guardians->shouldReceive('updateChild')->once()->with(5, 42, 'Ada L', '2015-04-02')->andReturn(true);
+        $this->guardians->shouldReceive('updateChild')->once()->with(5, 42, 'Ada L', '2015-04-02')->andReturn(null);
 
         $captured = null;
         $this->capturingPage($captured)->maybeHandleSubmit();
@@ -194,7 +194,7 @@ class FamilyPageTest extends TestCase
     {
         $_POST = ['us_family_action' => 'remove', 'child_id' => '42'];
 
-        $this->guardians->shouldReceive('removeChild')->once()->with(5, 42)->andReturn(true);
+        $this->guardians->shouldReceive('removeChild')->once()->with(5, 42)->andReturn(null);
 
         $captured = null;
         $this->capturingPage($captured)->maybeHandleSubmit();

tests/Unit/Guardian/GuardianServiceTest.php

@@ -236,7 +236,7 @@ class GuardianServiceTest extends TestCase
             ->with(['ID' => 42, 'display_name' => 'Ada L', 'nickname' => 'Ada L'])
             ->andReturn(42);
 
-        self::assertTrue($this->service->updateChild(5, 42, 'Ada L', '2015-04-02'));
+        self::assertNull($this->service->updateChild(5, 42, 'Ada L', '2015-04-02'));
         self::assertSame('2015-04-02', $this->meta[42][GuardianService::META_DOB]);
     }
 
@@ -249,7 +249,7 @@ class GuardianServiceTest extends TestCase
 
         Functions\expect('wp_delete_user')->once()->with(42);
 
-        self::assertTrue($this->service->removeChild(5, 42));
+        self::assertNull($this->service->removeChild(5, 42));
     }
 
     /**