Break out more specific possibly defined offset errors

config.xsd

@@ -310,6 +310,8 @@
             <xs:element name="PossiblyNullPropertyFetch" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="PossiblyNullReference" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="PossiblyUndefinedArrayOffset" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="PossiblyUndefinedIntArrayOffset" type="IssueHandlerType" minOccurs="0" />
+            <xs:element name="PossiblyUndefinedStringArrayOffset" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="PossiblyUndefinedMethod" type="MethodIssueHandlerType" minOccurs="0" />
             <xs:element name="PossiblyUndefinedGlobalVariable" type="IssueHandlerType" minOccurs="0" />
             <xs:element name="PossiblyUndefinedVariable" type="IssueHandlerType" minOccurs="0" />

docs/running_psalm/issues.md

@@ -1951,6 +1951,32 @@ echo $arr["b"];
 
 ```
 
+### PossiblyUndefinedIntArrayOffset
+
+Emitted when the config flag `ensureArrayIntOffsetsExist` is set to `true` and an integer-keyed offset is not checked for existence
+
+```php
+/**
+ * @param array<int, string> $arr
+ */
+function foo(array $arr) : void {
+    echo $arr[0];
+}
+```
+
+### PossiblyUndefinedStringArrayOffset
+
+Emitted when the config flag `ensureArrayStringOffsetsExist` is set to `true` and an integer-keyed offset is not checked for existence
+
+```php
+/**
+ * @param array<string, string> $arr
+ */
+function foo(array $arr) : void {
+    echo $arr["hello"];
+}
+```
+
 ### PossiblyUndefinedGlobalVariable
 
 Emitted when trying to access a variable in the global scope that may not be defined

src/Psalm/Config.php

@@ -1272,6 +1272,12 @@ class Config
      */
     public static function getParentIssueType($issue_type)
     {
+        if ($issue_type === 'PossiblyUndefinedIntArrayOffset'
+            || $issue_type === 'PossiblyUndefinedStringArrayOffset'
+        ) {
+            return 'PossiblyUndefinedArrayOffset';
+        }
+
         if (strpos($issue_type, 'Possibly') === 0) {
             $stripped_issue_type = preg_replace('/^Possibly(False|Null)?/', '', $issue_type);
 

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

@@ -25,6 +25,8 @@ use Psalm\Issue\PossiblyNullArrayAccess;
 use Psalm\Issue\PossiblyNullArrayAssignment;
 use Psalm\Issue\PossiblyNullArrayOffset;
 use Psalm\Issue\PossiblyUndefinedArrayOffset;
+use Psalm\Issue\PossiblyUndefinedIntArrayOffset;
+use Psalm\Issue\PossiblyUndefinedStringArrayOffset;
 use Psalm\IssueBuffer;
 use Psalm\Type;
 use Psalm\Type\Atomic\ObjectLike;
@@ -1263,7 +1265,7 @@ class ArrayFetchAnalyzer
 
             if (!$found_match) {
                 if (IssueBuffer::accepts(
-                    new PossiblyUndefinedArrayOffset(
+                    new PossiblyUndefinedIntArrayOffset(
                         'Possibly undefined array offset \''
                             . $offset_type->getId() . '\' '
                             . 'is risky given expected type \''
@@ -1312,7 +1314,7 @@ class ArrayFetchAnalyzer
 
             if (!$found_match) {
                 if (IssueBuffer::accepts(
-                    new PossiblyUndefinedArrayOffset(
+                    new PossiblyUndefinedStringArrayOffset(
                         'Possibly undefined array offset \''
                             . $offset_type->getId() . '\' '
                             . 'is risky given expected type \''

src/Psalm/Issue/PossiblyUndefinedIntArrayOffset.php

@@ -0,0 +1,6 @@
+<?php
+namespace Psalm\Issue;
+
+class PossiblyUndefinedIntArrayOffset extends CodeIssue
+{
+}

src/Psalm/Issue/PossiblyUndefinedStringArrayOffset.php

@@ -0,0 +1,6 @@
+<?php
+namespace Psalm\Issue;
+
+class PossiblyUndefinedStringArrayOffset extends CodeIssue
+{
+}

tests/DocumentationTest.php

@@ -146,6 +146,15 @@ class DocumentationTest extends TestCase
             $this->project_analyzer->trackUnusedSuppressions();
         }
 
+        $is_array_offset_test = strpos($error_message, 'ArrayOffset') && strpos($error_message, 'PossiblyUndefined') !== false;
+
+        $this->project_analyzer->getConfig()->ensure_array_string_offsets_exist = $is_array_offset_test;
+        $this->project_analyzer->getConfig()->ensure_array_int_offsets_exist = $is_array_offset_test;
+
+        if (strpos($error_message, 'ArrayOffset')) {
+
+        }
+
         foreach ($error_levels as $error_level) {
             $this->project_analyzer->getCodebase()->config->setCustomErrorLevel($error_level, Config::REPORT_SUPPRESS);
         }