mysqli: implement type inference for union-types in sql queries (#294)

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

Author: staabm

src/Extensions/MysqliQueryDynamicReturnTypeExtension.php

@@ -100,23 +100,32 @@ public function getTypeFromMethodCall(MethodReflection $methodReflection, Method
     private function inferResultType(Expr $queryExpr, Scope $scope): ?Type
     {
         $queryReflection = new QueryReflection();
-        $queryString = $queryReflection->resolveQueryString($queryExpr, $scope);
-        if (null === $queryString) {
+        $queryStrings = $queryReflection->resolveQueryStrings($queryExpr, $scope);
+
+        $genericObjects = [];
+        foreach ($queryStrings as $queryString) {
+            $resultType = $queryReflection->getResultType($queryString, QueryReflector::FETCH_TYPE_ASSOC);
+
+            if (null === $resultType) {
+                return null;
+            }
+
+            $genericObjects[] = new GenericObjectType(mysqli_result::class, [$resultType]);
+        }
+
+        if (0 === \count($genericObjects)) {
             return null;
         }
 
-        $resultType = $queryReflection->getResultType($queryString, QueryReflector::FETCH_TYPE_ASSOC);
-        if ($resultType) {
-            if (QueryReflection::getRuntimeConfiguration()->throwsMysqliExceptions($this->phpVersion)) {
-                return new GenericObjectType(mysqli_result::class, [$resultType]);
-            }
+        $resultType = TypeCombinator::union(...$genericObjects);
 
+        if (!QueryReflection::getRuntimeConfiguration()->throwsMysqliExceptions($this->phpVersion)) {
             return TypeCombinator::union(
-                new GenericObjectType(mysqli_result::class, [$resultType]),
+                $resultType,
                 new ConstantBooleanType(false),
             );
         }
 
-        return null;
+        return $resultType;
     }
 }

tests/default/DbaInferenceTest.php

@@ -47,6 +47,7 @@ public function dataFileAsserts(): iterable
 
         yield from $this->gatherAssertTypes(__DIR__.'/data/bug254.php');
         yield from $this->gatherAssertTypes(__DIR__.'/data/pdo-union-result.php');
+        yield from $this->gatherAssertTypes(__DIR__.'/data/mysqli-union-result.php');
     }
 
     /**

tests/default/config/.phpstan-dba-mysqli.cache

@@ -0,0 +1,19 @@
+<?php
+
+namespace PdoUnionResult;
+
+use mysqli;
+use function PHPStan\Testing\assertType;
+
+class Foo
+{
+    public function doBar(mysqli $mysqli)
+    {
+        $queries = ['SELECT adaid FROM ada', 'SELECT email FROM ada'];
+
+        foreach ($queries as $query) {
+            $result = $mysqli->query($query);
+            assertType('mysqli_result<array{adaid: int<0, 4294967295>}>|mysqli_result<array{email: string}>', $result);
+        }
+    }
+}