Make cmd_showing_output work with subprocesses that use '\r'.

1 files changed, 7 insertions, 3 deletions

diff --git a/exec_utils.py b/exec_utils.py
index b52f52f..36d48fa 100644
--- a/exec_utils.py
+++ b/exec_utils.py
@@ -4,6 +4,7 @@ import atexit
 import logging
 import shlex
 import subprocess
+import sys
 from typing import List, Optional
 
 
@@ -11,16 +12,19 @@ logger = logging.getLogger(__file__)
 
 
 def cmd_showing_output(command: str) -> None:
+    line_enders = set([b'\n', b'\r'])
     p = subprocess.Popen(
         command,
         shell=True,
         bufsize=0,
         stdout=subprocess.PIPE,
         stderr=subprocess.PIPE,
+        universal_newlines=False,
     )
-    for line in iter(p.stdout.readline, b''):
-        print(line.decode('utf-8'), end='')
-    p.stdout.close()
+    for char in iter(lambda: p.stdout.read(1), b''):
+        sys.stdout.buffer.write(char)
+        if char in line_enders:
+            sys.stdout.flush()
     p.wait()