diffs: fixed problem with rendering no newline at the end of file markers.

- fixes  #5402

rhodecode/tests/fixtures/hg_diff_no_newline.diff

@@ -0,0 +1,10 b''
+diff --git a/server.properties b/server.properties
+--- a/server.properties
++++ b/server.properties
+@@ -1,2 +1,3 @@
+property=value
+-anotherProperty=value
+\ No newline at end of file
++anotherProperty=value
++newProperty=super_important_value
+\ No newline at end of file
  No newline at end of file

rhodecode/lib/codeblocks.py

@@ -553,6 +553,23 b' class DiffSet(object):'
         # line 6: """
 
         lines = []
+
+        before_newline = AttributeDict()
+        after_newline = AttributeDict()
+        if before_lines and before_lines[-1]['action'] == 'old-no-nl':
+            before_newline_line = before_lines.pop(-1)
+            before_newline.content = '\n {}'.format(
+                render_tokenstream(
+                    [(x[0], '', x[1])
+                     for x in [('nonl', before_newline_line['line'])]]))
+
+        if after_lines and after_lines[-1]['action'] == 'new-no-nl':
+            after_newline_line = after_lines.pop(-1)
+            after_newline.content = '\n {}'.format(
+                render_tokenstream(
+                    [(x[0], '', x[1])
+                     for x in [('nonl', after_newline_line['line'])]]))
+
         while before_lines or after_lines:
             before, after = None, None
             before_tokens, after_tokens = None, None
@@ -605,6 +622,13 b' class DiffSet(object):'
                 modified.content = render_tokenstream(
                     [(x[0], '', x[1]) for x in after_tokens])
 
+            if not before_lines and before_newline:
+                original.content += before_newline.content
+                before_newline = None
+            if not after_lines and after_newline:
+                modified.content += after_newline.content
+                after_newline = None
+
             lines.append(AttributeDict({
                 'original': original,
                 'modified': modified,

rhodecode/tests/lib/test_diffs.py

@@ -226,6 +226,14 b' DIFF_FIXTURES = ['
                 CHMOD_FILENODE: 'modified file chmod 100755 => 100644'}}),
       ]),
     ('hg',
+     'hg_diff_no_newline.diff',
+     [('server.properties', 'M',
+       {'added': 2,
+        'deleted': 1,
+        'binary': False,
+        'ops': {MOD_FILENODE: 'modified file'}}),
+      ]),
+    ('hg',
      'hg_diff_mod_file_and_rename.diff',
      [('README.rst', 'M',
        {'added': 3,