support mysqli_fetch* type inference

src/Extensions/MysqliFetchFnsDynamicReturnTypeExtension.php

@@ -0,0 +1,110 @@
+<?php
+
+declare(strict_types=1);
+
+namespace staabm\PHPStanDba\Extensions;
+
+use mysqli;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\FuncCall;
+use PhpParser\Node\Expr\MethodCall;
+use PHPStan\Analyser\Scope;
+use PHPStan\Php\PhpVersion;
+use PHPStan\Reflection\FunctionReflection;
+use PHPStan\Reflection\MethodReflection;
+use PHPStan\Reflection\ParametersAcceptorSelector;
+use PHPStan\Type\Constant\ConstantBooleanType;
+use PHPStan\Type\DynamicFunctionReturnTypeExtension;
+use PHPStan\Type\DynamicFunctionThrowTypeExtension;
+use PHPStan\Type\DynamicMethodReturnTypeExtension;
+use PHPStan\Type\MixedType;
+use PHPStan\Type\Type;
+use PHPStan\Type\TypeCombinator;
+use staabm\PHPStanDba\MysqliReflection\MysqliResultObjectType;
+use staabm\PHPStanDba\QueryReflection\QueryReflection;
+use staabm\PHPStanDba\QueryReflection\QueryReflector;
+use staabm\PHPStanDba\UnresolvableQueryException;
+
+final class MysqliQueryDynamicReturnTypeExtension implements DynamicFunctionReturnTypeExtension
+{
+    /**
+     * @var PhpVersion
+     */
+    private $phpVersion;
+
+    public function __construct(PhpVersion $phpVersion)
+    {
+        $this->phpVersion = $phpVersion;
+    }
+
+    public function isFunctionSupported(FunctionReflection $functionReflection): bool
+    {
+        return in_array(strtolower($functionReflection->getName()), ['mysqli_fetch_assoc', 'mysqli_fetch_row', 'mysqli_fetch_object', 'mysqli_fetch_array'], true);
+    }
+
+    public function getTypeFromFunctionCall(FunctionReflection $functionReflection, FuncCall $functionCall, Scope $scope): Type
+    {
+        $args = $functionCall->getArgs();
+        $defaultReturn = ParametersAcceptorSelector::selectSingle($functionReflection->getVariants())->getReturnType();
+
+        if (QueryReflection::getRuntimeConfiguration()->throwsMysqliExceptions($this->phpVersion)) {
+            $defaultReturn = TypeCombinator::remove($defaultReturn, new ConstantBooleanType(false));
+        }
+
+        if (\count($args) < 1) {
+            return $defaultReturn;
+        }
+
+        try {
+            $resultType = $this->inferResultType($args[1]->value, $scope);
+            if (null !== $resultType) {
+                return $resultType;
+            }
+        } catch (UnresolvableQueryException $e) {
+            // simulation not possible.. use default value
+        }
+
+        return $defaultReturn;
+    }
+
+    /**
+     * @throws UnresolvableQueryException
+     */
+    private function inferResultType(Expr $mysqliExpr, Scope $scope): ?Type
+    {
+        $mysqliType = $scope->getType($mysqliExpr);
+
+        if (!$mysqliType instanceof MysqliResultObjectType) {
+            return null;
+        }
+
+        $queryReflection = new QueryReflection();
+        $queryStrings = $queryReflection->resolveQueryStrings($mysqliExpr, $scope);
+
+        $genericObjects = [];
+        foreach ($queryStrings as $queryString) {
+            $resultType = $queryReflection->getResultType($queryString, QueryReflector::FETCH_TYPE_ASSOC);
+
+            if (null === $resultType) {
+                return null;
+            }
+
+            $genericObjects[] = new MysqliResultObjectType($resultType);
+        }
+
+        if (0 === \count($genericObjects)) {
+            return null;
+        }
+
+        $resultType = TypeCombinator::union(...$genericObjects);
+
+        if (!QueryReflection::getRuntimeConfiguration()->throwsMysqliExceptions($this->phpVersion)) {
+            return TypeCombinator::union(
+                $resultType,
+                new ConstantBooleanType(false),
+            );
+        }
+
+        return $resultType;
+    }
+}

src/MysqliReflection/MysqliResultReflection.php

@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace staabm\PHPStanDba\MysqliReflection;
+
+final class MysqliResultReflection {
+
+}

tests/default/data/mysqli.php

@@ -46,4 +46,27 @@ public function fnQuery(mysqli $mysqli, string $query)
         $result = mysqli_query($mysqli, $query);
         assertType('mysqli_result|true', $result);
     }
+
+    public function fnFetchTypes(mysqli $mysqli)
+    {
+        $result = mysqli_query($mysqli, 'SELECT email, adaid FROM ada');
+        assertType('mysqli_result<array{email: string, adaid: int<-32768, 32767>}>', $result);
+
+        while ($row = mysqli_fetch_assoc($result)) {
+            assertType('array{email: string, adaid: int<-32768, 32767>}', $row);
+        }
+
+        while ($row = mysqli_fetch_row($result)) {
+            assertType('array{string, int<-32768, 32767>}', $row);
+        }
+
+        while ($row = mysqli_fetch_object($result)) {
+            assertType('int<-32768, 32767>', $row->adaid);
+            assertType('string', $row->email);
+        }
+
+        while ($row = mysqli_fetch_array($result)) {
+            assertType('array{0: string, 1: int<-32768, 32767>, email: string, adaid: int<-32768, 32767>}', $row);
+        }
+    }
 }