From e411b6629fb5f7bc01bec89df75737875ce6d8f5 Mon Sep 17 00:00:00 2001
From: Dingyuan Wang <abcdoyle888@gmail.com>
Date: Mon, 22 Jun 2015 10:01:12 +0800
Subject: [PATCH] Issue #20387: Restore retention of indentation during
 untokenize.

---
 Lib/tokenize.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index cf18bf9f2db..4d93a83e29d 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -244,6 +244,8 @@ class Untokenizer:
 
     def untokenize(self, iterable):
         it = iter(iterable)
+        indents = []
+        startline = False
         for t in it:
             if len(t) == 2:
                 self.compat(t, it)
@@ -254,6 +256,21 @@ class Untokenizer:
                 continue
             if tok_type == ENDMARKER:
                 break
+            if tok_type == INDENT:
+                indents.append(token)
+                continue
+            elif tok_type == DEDENT:
+                indents.pop()
+                self.prev_row, self.prev_col = end
+                continue
+            elif tok_type in (NEWLINE, NL):
+                startline = True
+            elif startline and indents:
+                indent = indents[-1]
+                if start[1] >= len(indent):
+                    self.tokens.append(indent)
+                    self.prev_col = len(indent)
+                startline = False
             self.add_whitespace(start)
             self.tokens.append(token)
             self.prev_row, self.prev_col = end