Merge pull request #215 from fix-205

Fix #205: stop gutter drift from phantom newline rows

internal/web/static/paste-lines.js

@@ -17,7 +17,10 @@
   // because HighlightCode highlights per line) in a .codeline block. The
   // spans are display:block, so they are joined with '' — a '\n' join leaves
   // newline text nodes between blocks that pre-wrap renders as an extra line
-  // box per line, which would shift every following number down one row (#167).
+  // box per line, which would shift every following number down one row (#167,
+  // #205). Whitespace-only text nodes are also stripped defensively below: any
+  // that reach the DOM (older cached HTML, other templates) render as phantom
+  // rows under white-space: pre and drift the gutter.
   function splitLines() {
     var html = body.innerHTML;
     var parts = html.split('\n');
@@ -26,6 +29,12 @@
       out.push('<span class="codeline">' + parts[i] + '</span>');
     }
     body.innerHTML = out.join('');
+    // #205: strip whitespace-only text nodes between the .codeline blocks.
+    var ws = [];
+    for (var n = body.firstChild; n; n = n.nextSibling) {
+      if (n.nodeType === 3 && !/\S/.test(n.nodeValue)) ws.push(n);
+    }
+    for (var w = 0; w < ws.length; w++) body.removeChild(ws[w]);
   }
 
   // One .gutline block per visual row. The gutter must reproduce the code