MDL-76966 assignfeedback_editpdf: Perform escapeshellarg without pageno

Author: djarran

mod/assign/feedback/editpdf/classes/pdf.php

@@ -694,8 +694,9 @@ private function get_gs_command_for_image(int $pageno, string $imagefile): strin
             $firstpage = $pagenoinc;
             $lastpage = $pagenoinc;
         } else {
-            // Convert all pages at once.
-            $imagefilearg = \escapeshellarg($imagefile . '%d.png');
+            // Convert all pages at once. Ensure that %d is not replaced by escapeshellarg on Windows systems.
+            $imagefilearg = \escapeshellarg($imagefile);
+            $imagefilearg = substr($imagefilearg, 0, -1) . '%d.png' . substr($imagefilearg, -1);
             $firstpage = 1;
             $lastpage = $this->pagecount;
         }

mod/assign/feedback/editpdf/tests/feedback_test.php

@@ -246,10 +246,15 @@ public function test_document_services(): void {
         $this->assertEquals($combinedpdf->get_contenthash(), document_services::BLANK_PDF_HASH);
 
         // Generate page images and verify that the combined pdf has been replaced.
-        document_services::get_page_images_for_attempt($assign, $student->id, -1);
+        $pageimages = document_services::get_page_images_for_attempt($assign, $student->id, -1);
         $combinedpdf = $fs->get_file($contextid, $component, $filearea, $itemid, $filepath, $filename);
         $this->assertNotEquals($combinedpdf->get_contenthash(), document_services::BLANK_PDF_HASH);
 
+        // Verify that the file name contains the page number from Ghostscript.
+        foreach ($pageimages as $index => $image) {
+            $this->assertTrue(str_contains($image->get_filename(), "page{$index}"));
+        }
+
         $notempty = page_editor::has_annotations_or_comments($grade->id, false);
         $this->assertFalse($notempty);