From f035c00a21c6dfb3d6887b56d1da524c655dd19d Mon Sep 17 00:00:00 2001
From: kkmuffme <11071985+kkmuffme@users.noreply.github.com>
Date: Mon, 19 Feb 2024 11:32:52 +0100
Subject: [PATCH] Fix non-empty-lowercase-string handling with literal
 non-lowercase strings

* Fix https://github.com/vimeo/psalm/issues/9782 and related issues
* add explicit handling for non-falsy-string to not fallback non-falsy-string and 0 to string
---
 src/Psalm/Internal/Type/TypeCombiner.php | 37 +++++++++++++++++++++++-
 tests/TypeCombinationTest.php            | 34 ++++++++++++++++++++++
 2 files changed, 70 insertions(+), 1 deletion(-)

diff --git a/src/Psalm/Internal/Type/TypeCombiner.php b/src/Psalm/Internal/Type/TypeCombiner.php
index e21d41b0559..0a084e8a62f 100644
--- a/src/Psalm/Internal/Type/TypeCombiner.php
+++ b/src/Psalm/Internal/Type/TypeCombiner.php
@@ -1103,18 +1103,53 @@ private static function scrapeStringProperties(
                         } else {
                             $combination->value_types['string'] = $type;
                         }
+                    } elseif ($type instanceof TNonFalsyString) {
+                        $has_empty_string = false;
+                        $has_falsy_string = false;
+
+                        foreach ($combination->strings as $string_type) {
+                            if ($string_type->value === '') {
+                                $has_empty_string = true;
+                                $has_falsy_string = true;
+                                break;
+                            }
+
+                            if ($string_type->value === '0') {
+                                $has_falsy_string = true;
+                            }
+                        }
+
+                        if ($has_empty_string) {
+                            $combination->value_types['string'] = new TString();
+                        } elseif ($has_falsy_string) {
+                            $combination->value_types['string'] = new TNonEmptyString();
+                        } else {
+                            $combination->value_types['string'] = $type;
+                        }
                     } elseif ($type instanceof TNonEmptyString) {
                         $has_empty_string = false;
 
                         foreach ($combination->strings as $string_type) {
-                            if (!$string_type->value) {
+                            if ($string_type->value === '') {
                                 $has_empty_string = true;
                                 break;
                             }
                         }
 
+                        $has_non_lowercase_string = false;
+                        if ($type instanceof TNonEmptyLowercaseString) {
+                            foreach ($combination->strings as $string_type) {
+                                if (strtolower($string_type->value) !== $string_type->value) {
+                                    $has_non_lowercase_string = true;
+                                    break;
+                                }
+                            }
+                        }
+
                         if ($has_empty_string) {
                             $combination->value_types['string'] = new TString();
+                        } elseif ($has_non_lowercase_string && get_class($type) !== TNonEmptyString::class) {
+                            $combination->value_types['string'] = new TNonEmptyString();
                         } else {
                             $combination->value_types['string'] = $type;
                         }
diff --git a/tests/TypeCombinationTest.php b/tests/TypeCombinationTest.php
index 56af82a69ed..ba3ded5e83d 100644
--- a/tests/TypeCombinationTest.php
+++ b/tests/TypeCombinationTest.php
@@ -127,6 +127,40 @@ function takesLiteralString($arg) {}
                     '$x===' => 'non-falsy-string',
                 ],
             ],
+            'loopNonFalsyWithZeroShouldBeNonEmpty' => [
+                'code' => '<?php
+                    /**
+                     * @psalm-suppress InvalidReturnType
+                     * @return string[]
+                     */
+                    function getStringArray() {}
+
+                    $x = array();
+                    foreach (getStringArray() as $id) {
+                        $x[] = "0";
+                        $x[] = "some_" . $id;
+                    }',
+                'assertions' => [
+                    '$x===' => 'list<non-empty-string>',
+                ],
+            ],
+            'loopNonLowercaseLiteralWithNonEmptyLowercaseShouldBeNonEmptyAndNotLowercase' => [
+                'code' => '<?php
+                    /**
+                     * @psalm-suppress InvalidReturnType
+                     * @return int[]
+                     */
+                    function getIntArray() {}
+
+                    $x = array();
+                    foreach (getIntArray() as $id) {
+                        $x[] = "TEXT";
+                        $x[] = "some_" . $id;
+                    }',
+                'assertions' => [
+                    '$x===' => 'list<non-empty-string>',
+                ],
+            ],
         ];
     }