From b5259ab78054a91f10804de460128879f7948ca4 Mon Sep 17 00:00:00 2001
From: Tom Forbes <tom@tomforb.es>
Date: Mon, 29 Apr 2019 10:07:00 +0200
Subject: [PATCH] Refs #30323 -- Simplified utils.autoreload.ensure_echo_on().

---
 django/utils/autoreload.py | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/django/utils/autoreload.py b/django/utils/autoreload.py
index 4a68fb05d0395..17631e15ef987 100644
--- a/django/utils/autoreload.py
+++ b/django/utils/autoreload.py
@@ -78,19 +78,22 @@ def raise_last_exception():
 
 
 def ensure_echo_on():
-    if termios:
-        fd = sys.stdin
-        if fd.isatty():
-            attr_list = termios.tcgetattr(fd)
-            if not attr_list[3] & termios.ECHO:
-                attr_list[3] |= termios.ECHO
-                if hasattr(signal, 'SIGTTOU'):
-                    old_handler = signal.signal(signal.SIGTTOU, signal.SIG_IGN)
-                else:
-                    old_handler = None
-                termios.tcsetattr(fd, termios.TCSANOW, attr_list)
-                if old_handler is not None:
-                    signal.signal(signal.SIGTTOU, old_handler)
+    """
+    Ensure that echo mode is enabled. Some tools such as PDB disable
+    it which causes usability issues after reload.
+    """
+    if not termios or not sys.stdin.isatty():
+        return
+    attr_list = termios.tcgetattr(sys.stdin)
+    if not attr_list[3] & termios.ECHO:
+        attr_list[3] |= termios.ECHO
+        if hasattr(signal, 'SIGTTOU'):
+            old_handler = signal.signal(signal.SIGTTOU, signal.SIG_IGN)
+        else:
+            old_handler = None
+        termios.tcsetattr(sys.stdin, termios.TCSANOW, attr_list)
+        if old_handler is not None:
+            signal.signal(signal.SIGTTOU, old_handler)
 
 
 def iter_all_python_module_files():