When no "V" entry exists, let the fieldValue fallback to the "DV" entry (issue 13823)

src/core/annotation.js

@@ -1193,6 +1193,12 @@ class WidgetAnnotation extends Annotation {
     });
     data.defaultFieldValue = this._decodeFormValue(defaultFieldValue);
 
+    // When no "V" entry exists, let the fieldValue fallback to the "DV" entry
+    // (fixes issue13823.pdf).
+    if (fieldValue === undefined && data.defaultFieldValue !== null) {
+      data.fieldValue = data.defaultFieldValue;
+    }
+
     data.alternativeText = stringToPDFString(dict.get("TU") || "");
 
     const defaultAppearance =

test/pdfs/issue13823.pdf.link

@@ -0,0 +1 @@
+https://github.com/mozilla/pdf.js/files/6907771/Formular_T_default.pdf

test/test_manifest.json

@@ -1038,6 +1038,14 @@
        "enableXfa": true,
        "type": "eq"
     },
+    {  "id": "issue13823",
+       "file": "pdfs/issue13823.pdf",
+       "md5": "8ca53bba9b2c68f5cd87f13a963e6b6a",
+       "rounds": 1,
+       "link": true,
+       "type": "eq",
+       "forms": true
+    },
     {  "id": "xfa_bug1718521_1",
        "file": "pdfs/xfa_bug1718521_1.pdf",
        "md5": "9b89dd9e6a4c6c3258ca24debd806863",