Fix phpGH-21705: ZipArchive::getFromIndex() ignores FL_UNCHANGED (php#21706)

ZipArchive::getFromIndex() already passed flags to zip_fopen_index(), but it
used an unflagged stat call to determine the entry size. Use the same flags
for the stat lookup so deleted entries can still be read with
ZipArchive::FL_UNCHANGED, matching ZipArchive::getFromName().

Closes php#21706

Author: LamentXU123

NEWS

@@ -65,6 +65,10 @@ PHP                                                                        NEWS
   . Fixed bug GH-22395 (base_convert() outputs at most 64 characters).
     (Weilin Du)
 
+- Zip:
+  . Fixed bug GH-21705 (ZipArchive::getFromIndex() ignores
+    ZipArchive::FL_UNCHANGED for deleted entries). (Weilin Du)
+
 02 Jul 2026, PHP 8.4.23
 
 - Core:

ext/zip/php_zip.c

@@ -2939,7 +2939,7 @@ static void php_zip_get_from(INTERNAL_FUNCTION_PARAMETERS, int type) /* {{{ */
 
 		ZIP_FROM_OBJECT(intern, self);
 
-		PHP_ZIP_STAT_INDEX(intern, index, 0, sb);
+		PHP_ZIP_STAT_INDEX(intern, index, flags, sb);
 	}
 
 	if (sb.size < 1) {

ext/zip/tests/bug_gh21705.phpt

@@ -0,0 +1,33 @@
+--TEST--
+ZipArchive::getFromIndex() honors FL_UNCHANGED for deleted entries
+--EXTENSIONS--
+zip
+--FILE--
+<?php
+$name = __DIR__ . '/bug_gh21705.zip';
+@unlink($name);
+$zip = new ZipArchive;
+$zip->open($name, ZipArchive::CREATE);
+$zip->addFromString('foo.txt', 'foo');
+$zip->addFromString('bar.txt', 'bar');
+$zip->close();
+
+$zip = new ZipArchive;
+$zip->open($name);
+
+$index = $zip->locateName('bar.txt');
+$zip->deleteName('bar.txt');
+
+var_dump($zip->getFromName('bar.txt', 0, ZipArchive::FL_UNCHANGED));
+var_dump($zip->getFromIndex($index, 0, ZipArchive::FL_UNCHANGED));
+
+$zip->close();
+?>
+--CLEAN--
+<?php
+$name = __DIR__ . '/bug_gh21705.zip';
+@unlink($name);
+?>
+--EXPECT--
+string(3) "bar"
+string(3) "bar"