Only add newlines for multiple uploads

app/assets/javascripts/dropzone_input.js

@@ -66,7 +66,10 @@ window.DropzoneInput = (function() {
         form_textarea.focus();
       },
       success: function(header, response) {
-        pasteText(response.link.markdown);
+        const processingFileCount = this.getQueuedFiles().length + this.getUploadingFiles().length;
+        const shouldPad = processingFileCount >= 1;
+
+        pasteText(response.link.markdown, shouldPad);
       },
       error: function(temp) {
         var checkIfMsgExists, errorAlert;
@@ -123,9 +126,10 @@ window.DropzoneInput = (function() {
       }
       return false;
     };
-    pasteText = function(text) {
+    pasteText = function(text, shouldPad) {
       var afterSelection, beforeSelection, caretEnd, caretStart, textEnd;
-      var formattedText = text + "\n\n";
+      var formattedText = text;
+      if (shouldPad) formattedText += "\n\n";
       caretStart = $(child)[0].selectionStart;
       caretEnd = $(child)[0].selectionEnd;
       textEnd = $(child).val().length;

changelogs/unreleased/remove-double-newline-for-single-attachments.yml

+---
+title: Only add newlines between multiple uploads
+merge_request: 10545
+author:

spec/features/issues_spec.rb

@@ -601,10 +601,10 @@ describe 'Issues', feature: true do
         expect(page.find_field("issue_description").value).to have_content 'banana_sample'
       end
 
-      it 'adds double newline to end of attachment markdown' do
+      it "doesn't add double newline to end of a single attachment markdown" do
         dropzone_file Rails.root.join('spec', 'fixtures', 'banana_sample.gif')
 
-        expect(page.find_field("issue_description").value).to match /\n\n$/
+        expect(page.find_field("issue_description").value).not_to match /\n\n$/
       end
     end