Improve salt.utils.build_whitepace_splited_regex(). Fixes #2379.

* Although we're building a regex which should ignore white space and new lines, the built regex should always match start and end of string.

salt/utils/__init__.py

@@ -562,12 +562,8 @@ def build_whitepace_splited_regex(text):
     regex = r''
     for line in text.splitlines():
         parts = [re.escape(s) for s in __build_parts(line)]
-        regex += r'(?:(?:[^])?(?:[\s]+)?|(?:[\s]+)?)'
-        regex += r'{0}'.format(
-            r'(?:(?:[^])?(?:[\s]+)?|(?:[\s]+)?)'.join(parts)
-        )
-        regex += r'(?:(?:[^])?(?:[\s]+)?|(?:[\s]+)?)'
-    return regex
+        regex += r'(?:[\s]+)?{0}(?:[\s]+)?'.format(r'(?:[\s]+)?'.join(parts))
+    return r'^{0}$'.format(regex)
 
 
 def format_call(fun, data):

tests/integration/states/file.py

@@ -526,6 +526,40 @@ class FileTest(integration.ModuleCase):
             if os.path.isfile(tmp_file):
                 os.remove(tmp_file)
 
+    def test_issue_2379_file_append(self):
+        # Get a path to the temporary file
+        tmp_file = os.path.join(integration.TMP, 'issue-2379-file-append.txt')
+        # Write some data to it
+        open(tmp_file, 'w').write(
+            'hello\nworld\n' +          # Some junk
+            '#PermitRootLogin yes\n' +  # Commented text
+            '# PermitRootLogin yes\n'   # Commented text with space
+        )
+        # create the sls template
+        template_lines = [
+            "{0}:".format(tmp_file),
+            "  file.append:",
+            "    - text: PermitRootLogin yes"
+        ]
+        template = '\n'.join(template_lines)
+        try:
+            ret = self.run_function('state.template_str', [template])
+
+            self.assertTrue(isinstance(ret, dict)), ret
+            self.assertNotEqual(ret, {})
+
+            for part in ret.itervalues():
+                self.assertTrue(part['result'])
+                self.assertEqual(
+                    part['comment'], 'Appended 1 lines'
+                )
+        except AssertionError:
+            shutil.copy(tmp_file, tmp_file + '.bak')
+            raise
+        finally:
+            if os.path.isfile(tmp_file):
+                os.remove(tmp_file)
+
 
 if __name__ == '__main__':
     from integration import run_tests