Makes is_pipeline accept empty list

Author: GromNaN

src/Operation/Aggregate.php

@@ -138,8 +138,7 @@ class Aggregate implements Executable, Explainable
      */
     public function __construct(string $databaseName, ?string $collectionName, array $pipeline, array $options = [])
     {
-        // Empty pipelines are allowed
-        if ($pipeline !== [] && ! is_pipeline($pipeline)) {
+        if (! is_pipeline($pipeline)) {
             throw new InvalidArgumentException('$pipeline is not a valid aggregation pipeline');
         }
 

src/Operation/BulkWrite.php

@@ -229,7 +229,7 @@ public function __construct(string $databaseName, string $collectionName, array
                         throw InvalidArgumentException::invalidType(sprintf('$operations[%d]["%s"][1]', $i, $type), $args[1], 'array or object');
                     }
 
-                    if (! is_first_key_operator($args[1]) && ! is_pipeline($args[1])) {
+                    if ($args[1] === [] || ! is_first_key_operator($args[1]) && ! is_pipeline($args[1])) {
                         throw new InvalidArgumentException(sprintf('First key in $operations[%d]["%s"][1] is neither an update operator nor a pipeline', $i, $type));
                     }
 

src/Operation/FindOneAndUpdate.php

@@ -114,7 +114,7 @@ public function __construct(string $databaseName, string $collectionName, $filte
             throw InvalidArgumentException::invalidType('$update', $update, 'array or object');
         }
 
-        if (! is_first_key_operator($update) && ! is_pipeline($update)) {
+        if ($update === [] || ! is_first_key_operator($update) && ! is_pipeline($update)) {
             throw new InvalidArgumentException('Expected an update document with operator as first key or a pipeline');
         }
 

src/Operation/ReplaceOne.php

@@ -90,7 +90,7 @@ public function __construct(string $databaseName, string $collectionName, $filte
             throw new InvalidArgumentException('First key in $replacement argument is an update operator');
         }
 
-        if (is_pipeline($replacement)) {
+        if ($replacement !== [] && is_pipeline($replacement)) {
             throw new InvalidArgumentException('$replacement argument is a pipeline');
         }
 

src/Operation/Update.php

@@ -147,7 +147,7 @@ public function __construct(string $databaseName, string $collectionName, $filte
             throw InvalidArgumentException::invalidType('"multi" option', $options['multi'], 'boolean');
         }
 
-        if ($options['multi'] && ! is_first_key_operator($update) && ! is_pipeline($update)) {
+        if ($options['multi'] && ($update === [] || ! is_first_key_operator($update) && ! is_pipeline($update))) {
             throw new InvalidArgumentException('"multi" option cannot be true if $update is a replacement document');
         }
 

src/Operation/UpdateMany.php

@@ -89,7 +89,7 @@ public function __construct(string $databaseName, string $collectionName, $filte
             throw InvalidArgumentException::invalidType('$update', $update, 'array or object');
         }
 
-        if (! is_first_key_operator($update) && ! is_pipeline($update)) {
+        if ($update === [] || ! is_first_key_operator($update) && ! is_pipeline($update)) {
             throw new InvalidArgumentException('Expected an update document with operator as first key or a pipeline');
         }
 

src/Operation/UpdateOne.php

@@ -89,7 +89,7 @@ public function __construct(string $databaseName, string $collectionName, $filte
             throw InvalidArgumentException::invalidType('$update', $update, 'array or object');
         }
 
-        if (! is_first_key_operator($update) && ! is_pipeline($update)) {
+        if ($update === [] || ! is_first_key_operator($update) && ! is_pipeline($update)) {
             throw new InvalidArgumentException('Expected an update document with operator as first key or a pipeline');
         }
 

src/functions.php

@@ -265,7 +265,7 @@ function is_pipeline($pipeline): bool
     }
 
     if ($pipeline === []) {
-        return false;
+        return true;
     }
 
     $expectedKey = 0;

tests/FunctionsTest.php

@@ -281,6 +281,7 @@ public function providePipelines(): array
 
         return [
             // Valid pipeline in various forms
+            'valid: empty array' => [true, []],
             'valid: array' => [true, $valid],
             'valid: Serializable' => [true, new BSONArray($valid)],
             'valid: PackedArray' => [true, PackedArray::fromPHP($valid)],

tests/Operation/BulkWriteTest.php

@@ -236,12 +236,13 @@ public function testUpdateManyUpdateArgumentTypeCheck($update): void
         ]);
     }
 
-    public function testUpdateManyUpdateArgumentRequiresOperatorsOrPipeline(): void
+    /** @dataProvider provideInvalidOperatorsOrPipeline */
+    public function testUpdateManyUpdateArgumentRequiresOperatorsOrPipeline($arg1): void
     {
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('First key in $operations[0]["updateMany"][1] is neither an update operator nor a pipeline');
         new BulkWrite($this->getDatabaseName(), $this->getCollectionName(), [
-            [BulkWrite::UPDATE_MANY => [['_id' => ['$gt' => 1]], ['x' => 1]]],
+            [BulkWrite::UPDATE_MANY => [['_id' => ['$gt' => 1]], $arg1]],
         ]);
     }
 
@@ -313,12 +314,13 @@ public function testUpdateOneUpdateArgumentTypeCheck($update): void
         ]);
     }
 
-    public function testUpdateOneUpdateArgumentRequiresOperatorsOrPipeline(): void
+    /** @dataProvider provideInvalidOperatorsOrPipeline */
+    public function testUpdateOneUpdateArgumentRequiresOperatorsOrPipeline($arg1): void
     {
         $this->expectException(InvalidArgumentException::class);
         $this->expectExceptionMessage('First key in $operations[0]["updateOne"][1] is neither an update operator nor a pipeline');
         new BulkWrite($this->getDatabaseName(), $this->getCollectionName(), [
-            [BulkWrite::UPDATE_ONE => [['_id' => 1], ['x' => 1]]],
+            [BulkWrite::UPDATE_ONE => [['_id' => 1], $arg1]],
         ]);
     }
 
@@ -386,4 +388,12 @@ public function provideInvalidConstructorOptions()
 
         return $options;
     }
+
+    public function provideInvalidOperatorsOrPipeline()
+    {
+        return $this->wrapValuesForDataProvider([
+            [],
+            ['x' => 1],
+        ]);
+    }
 }

tests/Operation/ReplaceOneTest.php

@@ -37,6 +37,7 @@ public function testConstructorReplacementArgument($replacement): void
     public function provideReplacementDocuments()
     {
         return $this->wrapValuesForDataProvider([
+            [],
             ['y' => 1],
             (object) ['y' => 1],
             new BSONDocument(['y' => 1]),