Properly count newlines appearing at the end of templates after rendering

Fixes #4633

lib/ansible/utils/string_functions.py

@@ -5,3 +5,11 @@ def isprintable(instring):
     isprintable = set(instring).issubset(printset)
     return isprintable
 
+def count_newlines_from_end(str):
+    i = len(str)
+    while i > 0:
+        if str[i-1] != '\n':
+            break
+        i -= 1
+    return len(str) - i
+

lib/ansible/utils/template.py

@@ -32,6 +32,8 @@ import pwd
 import ast
 import traceback
 
+from ansible.utils.string_functions import count_newlines_from_end
+
 class Globals(object):
 
     FILTERS = None
@@ -495,8 +497,14 @@ def template_from_file(basedir, path, vars):
     except jinja2.exceptions.UndefinedError, e:
         raise errors.AnsibleUndefinedVariable("One or more undefined variables: %s" % str(e))
 
-    if data.endswith('\n') and not res.endswith('\n'):
-        res = res + '\n'
+    # The low level calls above do not preserve the newline
+    # characters at the end of the input data, so we use the
+    # calculate the difference in newlines and append them 
+    # to the resulting output for parity
+    res_newlines  = count_newlines_from_end(res)
+    data_newlines = count_newlines_from_end(data)
+    if data_newlines > res_newlines:
+        res += '\n' * (data_newlines - res_newlines)
 
     if isinstance(res, unicode):
         # do not try to re-template a unicode string