Fix loading an extra element when not necessary

CHANGELOG.md

@@ -10,6 +10,7 @@
 
 - When a deferred `Set` or `Sequence` is used while iterating over itself it could produce unexpected results such as infinite loops or skipped values.
 - Fix iterating over a closed `\Generator` on a deferred `Set`/`Sequence` when the source monad no longer exist and the monad at hand has already been iterated over.
+- A deferred `Sequence` would load an extra element that is never used when calling `take`.
 
 ## 5.11.2 - 2025-02-23
 

proofs/sequence.php

@@ -435,6 +435,27 @@ static function($assert, $values) {
         },
     );
 
+    yield proof(
+        'Sequence::defer()->take() should not load an extra element',
+        given(
+            Set\Sequence::of(Set\Type::any()),
+        ),
+        static function($assert, $values) {
+            $sequence = Sequence::defer((static function() use ($values) {
+                yield from $values;
+
+                throw new Exception;
+            })())->take(\count($values));
+
+            $assert->not()->throws(
+                static fn() => $assert->same(
+                    $values,
+                    $sequence->toList(),
+                ),
+            );
+        },
+    );
+
     yield test(
         'Partial load a deferred Sequence appended to a lazy one',
         static function($assert) {

src/Sequence/Defer.php

@@ -625,6 +625,10 @@ public function take(int $size): Implementation
         /** @psalm-suppress ImpureFunctionCall */
         return new self(
             (static function(int $size) use (&$captured): \Generator {
+                if ($size === 0) {
+                    return;
+                }
+
                 $taken = 0;
                 /**
                  * @psalm-suppress PossiblyNullArgument
@@ -634,14 +638,15 @@ public function take(int $size): Implementation
                 $values->rewind();
 
                 while ($values->valid()) {
+                    yield $values->current();
+                    ++$taken;
+
                     if ($taken >= $size) {
                         $values->cleanup();
 
                         return;
                     }
 
-                    yield $values->current();
-                    ++$taken;
                     $values->next();
                 }
             })($size),