Fix assertions on unions

src/Psalm/Config/Creator.php

@@ -205,6 +205,7 @@ class Creator
      * @return list<string>
      * @psalm-suppress MixedAssignment
      * @psalm-suppress MixedArgument
+     * @psalm-suppress PossiblyUndefinedArrayOffset
      */
     private static function getPsr4Or0Paths(string $current_dir, array $composer_json) : array
     {

src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ArrayFetchAnalyzer.php

@@ -285,7 +285,7 @@ class ArrayFetchAnalyzer
                 if (IssueBuffer::accepts(
                     new PossiblyUndefinedArrayOffset(
                         'Possibly undefined array key ' . $keyed_array_var_id
-                            . ($stmt_var_type ? ' on ' . $stmt_var_type->getId() : ''),
+                            . ' on ' . $stmt_var_type->getId(),
                         new CodeLocation($statements_analyzer->getSource(), $stmt)
                     ),
                     $statements_analyzer->getSuppressedIssues()

src/Psalm/Type/Reconciler.php

@@ -614,6 +614,9 @@ class Reconciler
                             && ($has_isset || $has_inverted_isset)
                         ) {
                             $has_object_array_access = true;
+
+                            unset($existing_keys[$new_base_key]);
+
                             return null;
                         } elseif (!$existing_key_type_part instanceof Type\Atomic\TKeyedArray) {
                             return Type::getMixed();

src/command_functions.php

@@ -156,7 +156,8 @@ function getVendorDir(string $current_dir): string
         exit(1);
     }
 
-    if (isset($composer_json['config'])
+    if (is_array($composer_json)
+        && isset($composer_json['config'])
         && is_array($composer_json['config'])
         && isset($composer_json['config']['vendor-dir'])
         && is_string($composer_json['config']['vendor-dir'])

tests/ArrayAccessTest.php

@@ -368,7 +368,6 @@ class ArrayAccessTest extends TestCase
                     $a = new A();
                     /**
                      * @psalm-suppress UndefinedClass
-                     * @psalm-suppress PossiblyUndefinedArrayOffset
                      */
                     if (!isset($a->arr["bat"]) || strlen($a->arr["bat"])) { }',
                 'assertions' => [],
@@ -664,6 +663,13 @@ class ArrayAccessTest extends TestCase
             ],
             'arrayAccessOnObjectWithNullGet' => [
                 '<?php
+                    $array = new C([]);
+                    $array["key"] = [];
+                    /** @psalm-suppress PossiblyInvalidArrayAssignment */
+                    $array["key"][] = "testing";
+
+                    $c = isset($array["foo"]) ? $array["foo"] : null;
+
                     class C implements ArrayAccess
                     {
                         /**
@@ -738,14 +744,7 @@ class ArrayAccessTest extends TestCase
                         {
                             $this->__unset($offset);
                         }
-                    }
+                    }',
-
-                    $array = new C([]);
-                    $array["key"] = [];
-                    /** @psalm-suppress PossiblyInvalidArrayAssignment */
-                    $array["key"][] = "testing";
-
-                    $c = isset($array["foo"]) ? $array["foo"] : null;',
                 [
                     '$c' => 'C|null|scalar',
                 ]

tests/TypeReconciliation/IssetTest.php

@@ -1006,7 +1006,6 @@ class IssetTest extends \Psalm\Tests\TestCase
                         if (isset($param["name"])) {
                             /**
                              * @psalm-suppress MixedArgument
-                             * @psalm-suppress PossiblyUndefinedArrayOffset
                              */
                             echo $param["name"];
                         }
@@ -1029,6 +1028,18 @@ class IssetTest extends \Psalm\Tests\TestCase
                         return $a ?? $b;
                     }'
             ],
+            'nullCoalesceSimpleArrayOffset' => [
+                '<?php
+                    function a(array $arr) : void {
+                        /** @psalm-suppress MixedArgument */
+                        echo isset($arr["a"]["b"]) ? $arr["a"]["b"] : 0;
+                    }
+
+                    function b(array $arr) : void {
+                        /** @psalm-suppress MixedArgument */
+                        echo $arr["a"]["b"] ?? 0;
+                    }'
+            ],
         ];
     }