When merging pdfs, fix the CO after the fields have been cloned

src/core/editor/pdf_editor.js

@@ -1460,6 +1460,7 @@ class PDFEditor {
         this.currentDocument = null;
       }
     }
+    this.#setAcroFormCalculationOrder(allDocumentData);
   }
 
   #setAcroFormQ(allDocumentData) {
@@ -1495,7 +1496,6 @@ class PDFEditor {
   #setAcroFormDefaultBasicValues(allDocumentData) {
     let sigFlags = 0;
     let needAppearances = false;
-    const calculationOrder = [];
     for (const documentData of allDocumentData) {
       if (!documentData.acroForm) {
         continue;
@@ -1507,7 +1507,15 @@ class PDFEditor {
       if (documentData.acroForm.get("NeedAppearances") === true) {
         needAppearances = true;
       }
-      const co = documentData.acroForm.get("CO") || null;
+    }
+    this.acroFormSigFlags = sigFlags;
+    this.acroFormNeedAppearances = needAppearances;
+  }
+
+  #setAcroFormCalculationOrder(allDocumentData) {
+    const calculationOrder = [];
+    for (const documentData of allDocumentData) {
+      const co = documentData.acroForm?.get("CO") || null;
       if (!Array.isArray(co)) {
         continue;
       }
@@ -1519,8 +1527,6 @@ class PDFEditor {
         }
       }
     }
-    this.acroFormSigFlags = sigFlags;
-    this.acroFormNeedAppearances = needAppearances;
     this.acroFormCalculationOrder =
       calculationOrder.length > 0 ? calculationOrder : null;
   }

test/pdfs/.gitignore

@@ -886,3 +886,4 @@
 !radial_gradients.pdf
 !outlines_for_editor.pdf
 !mesh_shading_empty.pdf
+!acroform_calculation_order.pdf

test/pdfs/acroform_calculation_order.pdf

@@ -0,0 +1,48 @@
+%PDF-1.7
+1 0 obj
+<< /Type /Catalog /Pages 2 0 R /AcroForm 5 0 R >>
+endobj
+2 0 obj
+<< /Type /Pages /Kids [3 0 R] /Count 1 >>
+endobj
+3 0 obj
+<< /Type /Page /Parent 2 0 R /MediaBox [0 0 200 200] /Resources << /Font << /F1 9 0 R >> >> /Contents 4 0 R /Annots [7 0 R 8 0 R] >>
+endobj
+4 0 obj
+<< /Length 36 >>
+stream
+BT /F1 12 Tf 10 100 Td (Hello) Tj ET
+endstream
+endobj
+5 0 obj
+<< /Fields [6 0 R] /CO [6 0 R] /DA (/F1 12 Tf 0 g) >>
+endobj
+6 0 obj
+<< /FT /Tx /T (group) /Kids [7 0 R 8 0 R] /DA (/F1 12 Tf 0 g) >>
+endobj
+7 0 obj
+<< /Type /Annot /Subtype /Widget /Parent 6 0 R /Rect [10 150 90 170] /P 3 0 R >>
+endobj
+8 0 obj
+<< /Type /Annot /Subtype /Widget /Parent 6 0 R /Rect [10 120 90 140] /P 3 0 R >>
+endobj
+9 0 obj
+<< /Type /Font /Subtype /Type1 /BaseFont /Helvetica >>
+endobj
+xref
+0 10
+0000000000 65535 f 
+0000000009 00000 n 
+0000000074 00000 n 
+0000000131 00000 n 
+0000000279 00000 n 
+0000000365 00000 n 
+0000000434 00000 n 
+0000000514 00000 n 
+0000000610 00000 n 
+0000000706 00000 n 
+trailer
+<< /Size 10 /Root 1 0 R >>
+startxref
+776
+%%EOF

test/unit/api_spec.js

@@ -6329,6 +6329,34 @@ small scripts as well as for`);
 
         await loadingTask.destroy();
       });
+
+      it("preserves calculation order when it points to parent fields", async function () {
+        let loadingTask = getDocument(
+          buildGetDocumentParams("acroform_calculation_order.pdf")
+        );
+        let pdfDoc = await loadingTask.promise;
+
+        expect(await pdfDoc.getCalculationOrderIds()).toEqual(["6R"]);
+        expect(Object.keys((await pdfDoc.getFieldObjects()) || {})).toEqual([
+          "group",
+        ]);
+
+        const data = await pdfDoc.extractPages([{ document: null }]);
+        await loadingTask.destroy();
+
+        loadingTask = getDocument(data);
+        pdfDoc = await loadingTask.promise;
+
+        const calculationOrder = await pdfDoc.getCalculationOrderIds();
+        expect(Array.isArray(calculationOrder)).toEqual(true);
+        expect(calculationOrder.length).toEqual(1);
+        expect(calculationOrder[0]).not.toEqual("6R");
+        expect(Object.keys((await pdfDoc.getFieldObjects()) || {})).toEqual([
+          "group",
+        ]);
+
+        await loadingTask.destroy();
+      });
     });
 
     describe("Outlines", function () {