changeset 45043:be58fb1eaa73

procutil: make stdout line-buffered on Windows if connected to TTY

Windows doesn’t support line buffering. Previously, we worked around that by
setting the stream unbuffered. Instead, we can use our own line buffering we
already use on Python 3.

--- a/mercurial/utils/procutil.py	Sat Jul 04 11:21:44 2020 +0200
+++ b/mercurial/utils/procutil.py	Sat Jul 04 11:41:39 2020 +0200
@@ -84,23 +84,21 @@
 stdin = pycompat.stdin
 stdout = pycompat.stdout
 
+if pycompat.iswindows:
+    stdout = platform.winstdout(stdout)
+
 # glibc determines buffering on first write to stdout - if we replace a TTY
 # destined stdout with a pipe destined stdout (e.g. pager), we want line
-# buffering (or unbuffered, on Windows)
+# buffering.
 if isatty(stdout):
-    if pycompat.iswindows:
-        # Windows doesn't support line buffering
-        stdout = os.fdopen(stdout.fileno(), 'wb', 0)
-    elif pycompat.ispy3:
+    if pycompat.ispy3 or pycompat.iswindows:
         # On Python 3, buffered binary streams can't be set line-buffered.
+        # On Python 2, Windows doesn't support line buffering.
         # Therefore we have a wrapper that implements line buffering.
         stdout = make_line_buffered(stdout)
     else:
         stdout = os.fdopen(stdout.fileno(), 'wb', 1)
 
-if pycompat.iswindows:
-    stdout = platform.winstdout(stdout)
-
 
 findexe = platform.findexe
 _gethgcmd = platform.gethgcmd

--- a/tests/test-stdio.py	Sat Jul 04 11:21:44 2020 +0200
+++ b/tests/test-stdio.py	Sat Jul 04 11:41:39 2020 +0200
@@ -89,7 +89,6 @@
     def test_stdout_ptys_unbuffered(self):
         self._test(_ptys, UNBUFFERED, python_args=['-u'])
 
-    # On Windows, test_stdout_ptys wouldn't pass, but it's skipped anyway.
     if not pycompat.ispy3 and not pycompat.iswindows:
         # On Python 2 on non-Windows, we manually open stdout in line-buffered
         # mode if connected to a TTY. We should check if Python was configured