Fix vimeo#2165 - coerce null array offset to zero

AndrolGenhald · Sep 25, 2019 · 1a48be8 · 1a48be8
1 parent 2d621f1
commit 1a48be8
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Showing 2 changed files with 51 additions and 13 deletions.
diff --git a/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ArrayFetchAnalyzer.php b/src/Psalm/Internal/Analyzer/Statements/Expression/Fetch/ArrayFetchAnalyzer.php
@@ -273,8 +273,8 @@ public static function getArrayAccessTypeGivenOffset(
         PhpParser\Node\Expr\ArrayDimFetch $stmt,
         Type\Union $array_type,
         Type\Union $offset_type,
-        $in_assignment,
-        $array_var_id,
+        bool $in_assignment,
+        ?string $array_var_id,
         Context $context,
         PhpParser\Node\Expr $assign_value = null,
         Type\Union $replacement_type = null
@@ -326,19 +326,29 @@ public static function getArrayAccessTypeGivenOffset(
                 // fall through
             }
 
-            return Type::getMixed();
+            if ($in_assignment) {
+                $offset_type->removeType('null');
+                $offset_type->addType(new TLiteralInt(0));
+            }
         }
 
-        if ($offset_type->isNullable() && !$offset_type->ignore_nullable_issues && !$context->inside_isset) {
-            if (IssueBuffer::accepts(
-                new PossiblyNullArrayOffset(
-                    'Cannot access value on variable ' . $array_var_id
-                        . ' using possibly null offset ' . $offset_type,
-                    new CodeLocation($statements_analyzer->getSource(), $stmt->var)
-                ),
-                $statements_analyzer->getSuppressedIssues()
-            )) {
-                // fall through
+        if ($offset_type->isNullable() && !$context->inside_isset) {
+            if (!$offset_type->ignore_nullable_issues) {
+                if (IssueBuffer::accepts(
+                    new PossiblyNullArrayOffset(
+                        'Cannot access value on variable ' . $array_var_id
+                            . ' using possibly null offset ' . $offset_type,
+                        new CodeLocation($statements_analyzer->getSource(), $stmt->var)
+                    ),
+                    $statements_analyzer->getSuppressedIssues()
+                )) {
+                    // fall through
+                }
+            }
+
+            if ($in_assignment) {
+                $offset_type->removeType('null');
+                $offset_type->addType(new TLiteralInt(0));
             }
         }
 

diff --git a/tests/ArrayAssignmentTest.php b/tests/ArrayAssignmentTest.php
@@ -1117,6 +1117,34 @@ function foo(): array {
                         return $array;
                     }',
             ],
+            'coerceNullKeyToZero' => [
+                '<?php
+                    function int_or_null(): ?int {
+                      return rand(0, 1) !== 0 ? 42 : null;
+                    }
+
+                    /**
+                     * @return array<array-key, null>
+                     */
+                    function foo(): array {
+                        $array = [];
+                        /** @psalm-suppress PossiblyNullArrayOffset */
+                        $array[int_or_null()] = null;
+                        return $array;
+                    }'
+            ],
+            'coerceNullKeyToZero' => [
+                '<?php
+                    /**
+                     * @return array<int, null>
+                     */
+                    function foo(): array {
+                        $array = [];
+                        /** @psalm-suppress NullArrayOffset */
+                        $array[null] = null;
+                        return $array;
+                    }'
+            ],
         ];
     }