Add content attributes to discussion diffs; change styling of add-note icon to prevent white spaces in paste

app/assets/stylesheets/pages/diff.scss

@@ -69,10 +69,12 @@
 
         &.noteable_line.old:before {
           content: '-';
+          position: absolute;
         }
 
         &.noteable_line.new:before {
           content: '+';
+          position: absolute;
         }
 
         span {
@@ -400,14 +402,22 @@
   }
 }
 
-.diff-line-num:not(.js-unfold-bottom) {
-  a {
-    &:before {
-      content: attr(data-linenumber);
+.file-holder {
+  .diff-line-num:not(.js-unfold-bottom) {
+    a {
+      &:before {
+          content: attr(data-linenumber);
+      }
+    }
+  }
+}
+
+.discussion {
+  .diff-content {
+    .diff-line-num {
+      &:before {
+        content: attr(data-linenumber);
+      }
     }
-    -moz-user-select: none;
-    -webkit-user-select: none;
-    -ms-user-select: none;
-    user-select: none;
   }
 }

app/assets/stylesheets/pages/notes.scss

@@ -276,8 +276,7 @@ ul.notes {
 
 .diff-file tr.line_holder {
   @mixin show-add-diff-note {
-    filter: alpha(opacity=100);
-    opacity: 1.0;
+    display: inline-block;
   }
 
   .add-diff-note {
@@ -291,13 +290,8 @@ ul.notes {
     position: absolute;
     z-index: 10;
     width: 32px;
-
-    transition: all 0.2s ease;
-
     // "hide" it by default
-    opacity: 0.0;
-    filter: alpha(opacity=0);
-
+    display: none;
     &:hover {
       background: $gl-info;
       color: #fff;

app/views/projects/blob/diff.html.haml

@@ -9,9 +9,9 @@
     - line_old = line_new - @form.offset
     %tr.line_holder
       %td.old_line.diff-line-num{data: {linenumber: line_old}}
-        / = link_to raw(line_old), "#"
+        = link_to raw(line_old), "#"
       %td.new_line.diff-line-num{data: {linenumber: line_old}}
-        / = link_to raw(line_new) , "#"
+        = link_to raw(line_new) , "#"
       %td.line_content.noteable_line==#{' ' * @form.indent}#{line}
 
   - if @form.unfold? && @form.bottom? && @form.to < @blob.loc

app/views/projects/notes/discussions/_diff.html.haml

@@ -20,10 +20,8 @@
               %td.new_line.diff-line-num= "..."
               %td.line_content.match= line.text
             - else
-              %td.old_line.diff-line-num
-                = raw(type == "new" ? " " : line.old_pos)
-              %td.new_line.diff-line-num
-                = raw(type == "old" ? " " : line.new_pos)
+              %td.old_line.diff-line-num{data: {linenumber: raw(type == "new" ? " " : line.old_pos)}}
+              %td.new_line.diff-line-num{data: {linenumber: raw(type == "old" ? " " : line.new_pos)}}
               %td.line_content{class: "noteable_line #{type} #{line_code}", line_code: line_code}= diff_line_content(line.text)
 
               - if line_code == note.line_code