Fix file.line line endings

salt/utils/atomicfile.py

@@ -158,7 +158,12 @@ def atomic_open(filename, mode='w'):
     '''
     if mode in ('r', 'rb', 'r+', 'rb+', 'a', 'ab'):
         raise TypeError('Read or append modes don\'t work with atomic_open')
-    ntf = tempfile.NamedTemporaryFile(mode, prefix='.___atomic_write',
-                                      dir=os.path.dirname(filename),
-                                      delete=False)
+    kwargs = {
+        'prefix': '.___atomic_write',
+        'dir': os.path.dirname(filename),
+        'delete': False,
+    }
+    if six.PY3:
+        kwargs['newline'] = ''
+    ntf = tempfile.NamedTemporaryFile(mode, **kwargs)
     return _AtomicWFile(ntf, ntf.name, filename)

tests/integration/states/test_file.py

@@ -2404,6 +2404,32 @@ class FileTest(ModuleCase, SaltReturnAssertsMixin):
         self.assertEqual(pwd.getpwuid(temp_file_stats.st_uid).pw_name, user)
         self.assertEqual(grp.getgrgid(temp_file_stats.st_gid).gr_name, group)
 
+    @with_tempdir()
+    def test_issue_48557(self, tempdir):
+        tempfile = os.path.join(tempdir, 'temp_file_issue_48557')
+        with open(tempfile, 'wb') as fp:
+            fp.write(os.linesep.join([
+				'test1',
+                'test2',
+                'test3',
+                '',
+            ]).encode('utf-8'))
+        ret = self.run_state('file.line',
+                             name=tempfile,
+                             after='test2',
+                             mode='insert',
+                             content='test4')
+        self.assertSaltTrueReturn(ret)
+        with open(tempfile, 'rb') as fp:
+            content = fp.read()
+        self.assertEqual(content, os.linesep.join([
+            'test1',
+            'test2',
+            'test4',
+            'test3',
+            '',
+        ]).encode('utf-8'))
+
 
 class BlockreplaceTest(ModuleCase, SaltReturnAssertsMixin):
     marker_start = '# start'