Resolve "Copying ordered list to new comment becomes unordered"

app/assets/javascripts/lib/utils/common_utils.js

@@ -189,12 +189,25 @@ export const getParameterByName = (name, urlToParse) => {
   return decodeURIComponent(results[2].replace(/\+/g, ' '));
 };
 
+const handleSelectedRange = (range) => {
+  const container = range.commonAncestorContainer;
+  // add context to fragment if needed
+  if (container.tagName === 'OL') {
+    const parentContainer = document.createElement(container.tagName);
+    parentContainer.appendChild(range.cloneContents());
+    return parentContainer;
+  }
+  return range.cloneContents();
+};
+
 export const getSelectedFragment = () => {
   const selection = window.getSelection();
   if (selection.rangeCount === 0) return null;
   const documentFragment = document.createDocumentFragment();
+
   for (let i = 0; i < selection.rangeCount; i += 1) {
-    documentFragment.appendChild(selection.getRangeAt(i).cloneContents());
+    const range = selection.getRangeAt(i);
+    documentFragment.appendChild(handleSelectedRange(range));
   }
   if (documentFragment.textContent.length === 0) return null;
 

changelogs/unreleased/40484-ordered-lists-copy-gfm.yml

+---
+title: Keep lists ordered when copying only list items
+merge_request: 18522
+author: Jan Beckmann
+type: fixed

spec/javascripts/behaviors/copy_as_gfm_spec.js

@@ -44,4 +44,59 @@ describe('CopyAsGFM', () => {
       callPasteGFM();
     });
   });
+
+  describe('CopyAsGFM.copyGFM', () => {
+    // Stub getSelection to return a purpose-built object.
+    const stubSelection = (html, parentNode) => ({
+      getRangeAt: () => ({
+        commonAncestorContainer: { tagName: parentNode },
+        cloneContents: () => {
+          const fragment = document.createDocumentFragment();
+          const node = document.createElement('div');
+          node.innerHTML = html;
+          Array.from(node.childNodes).forEach((item) => fragment.appendChild(item));
+          return fragment;
+        },
+      }),
+      rangeCount: 1,
+    });
+
+    const clipboardData = {
+      setData() {},
+    };
+
+    const simulateCopy = () => {
+      const e = {
+        originalEvent: {
+          clipboardData,
+        },
+        preventDefault() {},
+        stopPropagation() {},
+      };
+      CopyAsGFM.copyAsGFM(e, CopyAsGFM.transformGFMSelection);
+      return clipboardData;
+    };
+
+    beforeEach(() => spyOn(clipboardData, 'setData'));
+
+    describe('list handling', () => {
+      it('uses correct gfm for unordered lists', () => {
+        const selection = stubSelection('<li>List Item1</li><li>List Item2</li>\n', 'UL');
+        spyOn(window, 'getSelection').and.returnValue(selection);
+        simulateCopy();
+
+        const expectedGFM = '- List Item1\n- List Item2';
+        expect(clipboardData.setData).toHaveBeenCalledWith('text/x-gfm', expectedGFM);
+      });
+
+      it('uses correct gfm for ordered lists', () => {
+        const selection = stubSelection('<li>List Item1</li><li>List Item2</li>\n', 'OL');
+        spyOn(window, 'getSelection').and.returnValue(selection);
+        simulateCopy();
+
+        const expectedGFM = '1. List Item1\n1. List Item2';
+        expect(clipboardData.setData).toHaveBeenCalledWith('text/x-gfm', expectedGFM);
+      });
+    });
+  });
 });