support PDOStatement::fetch() (#41)

Co-authored-by: Markus Staab <[email protected]>

Author: staabm

README.md

@@ -4,7 +4,7 @@ This extension provides following features:
 
 * the array shape of results can be inferred for `PDOStatement` and `mysqli_result`
   * .. when the query string can be resolved at analysis time. This is even possible for queries containing php-variables, as long as their typ is known in most cases.
-  * builtin we support `mysqli_query`, `mysqli->query`, `PDOStatement->fetchAll`, `PDO->query` and `PDO->prepare`
+  * builtin we support `mysqli_query`, `mysqli->query`, `PDOStatement->fetch`, `PDOStatement->fetchAll`, `PDO->query` and `PDO->prepare`
 * `PDO->prepare` knows the array shape of the returned results and therefore can return a generic `PDOStatement`
 * `mysqli->query` knows the array shape of the returned results and therefore can return a generic `mysqli_result`
 * `SyntaxErrorInQueryMethodRule` can inspect sql queries and detect syntax errors - `SyntaxErrorInQueryFunctionRule` can do the same for functions

src/Extensions/PdoStatementFetchDynamicReturnTypeExtension.php

@@ -13,12 +13,14 @@
 use PHPStan\Type\ArrayType;
 use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantArrayTypeBuilder;
+use PHPStan\Type\Constant\ConstantBooleanType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\DynamicMethodReturnTypeExtension;
 use PHPStan\Type\Generic\GenericObjectType;
 use PHPStan\Type\IntegerType;
 use PHPStan\Type\Type;
+use PHPStan\Type\UnionType;
 
 final class PdoStatementFetchDynamicReturnTypeExtension implements DynamicMethodReturnTypeExtension
 {
@@ -29,7 +31,7 @@ public function getClass(): string
 
     public function isMethodSupported(MethodReflection $methodReflection): bool
     {
-        return 'fetchAll' === $methodReflection->getName();
+        return \in_array($methodReflection->getName(), ['fetchAll', 'fetch'], true);
     }
 
     public function getTypeFromMethodCall(MethodReflection $methodReflection, MethodCall $methodCall, Scope $scope): Type
@@ -75,10 +77,18 @@ public function getTypeFromMethodCall(MethodReflection $methodReflection, Method
                     }
                 }
 
-                return new ArrayType(new IntegerType(), $builder->getArray());
+                if ('fetchAll' === $methodReflection->getName()) {
+                    return new ArrayType(new IntegerType(), $builder->getArray());
+                }
+
+                return new UnionType([$builder->getArray(), new ConstantBooleanType(false)]);
+            }
+
+            if ('fetchAll' === $methodReflection->getName()) {
+                return new ArrayType(new IntegerType(), $resultType);
             }
 
-            return new ArrayType(new IntegerType(), $resultType);
+            return new UnionType([$resultType, new ConstantBooleanType(false)]);
         }
 
         return $defaultReturn;

tests/data/pdo-stmt-fetch.php

@@ -30,4 +30,28 @@ public function fetchAll(PDO $pdo)
         $all = $stmt->fetchAll(PDO::FETCH_OBJ);
         assertType('array|false', $all); // XXX since php8 this cannot return false
     }
+
+    public function fetch(PDO $pdo)
+    {
+        $stmt = $pdo->prepare('SELECT email, adaid FROM ada');
+        $stmt->execute();
+        assertType('PDOStatement<array{email: string, 0: string, adaid: int<0, 4294967295>, 1: int<0, 4294967295>}>', $stmt);
+
+        // default fetch-mode is BOTH
+        $all = $stmt->fetch();
+        assertType('array{email: string, 0: string, adaid: int<0, 4294967295>, 1: int<0, 4294967295>}|false', $all);
+
+        $all = $stmt->fetch(PDO::FETCH_BOTH);
+        assertType('array{email: string, 0: string, adaid: int<0, 4294967295>, 1: int<0, 4294967295>}|false', $all);
+
+        $all = $stmt->fetch(PDO::FETCH_NUM);
+        assertType('array{string, int<0, 4294967295>}|false', $all);
+
+        $all = $stmt->fetch(PDO::FETCH_ASSOC);
+        assertType('array{email: string, adaid: int<0, 4294967295>}|false', $all);
+
+        // not yet supported fetch types
+        $all = $stmt->fetch(PDO::FETCH_OBJ);
+        assertType('mixed', $all);
+    }
 }