[PATCH] color: sync text attributes and buffered text output on Windows (issue5508)

Matt Harbison mharbison72 at gmail.com
Sun Mar 19 18:06:33 UTC 2017


# HG changeset patch
# User Matt Harbison <matt_harbison at yahoo.com>
# Date 1489941885 14400
#      Sun Mar 19 12:44:45 2017 -0400
# Node ID b1bebed54e9371708e1cd1eba63f0cedadfdf035
# Parent  da7d19324b1e3d2ce0636bf73e76bf8f3d68ed27
color: sync text attributes and buffered text output on Windows (issue5508)

I originally noticed that log output wasn't being colored after 3a4c0905f357,
but there were other complications too.  With a bunch of untracked files, only
the first 1K of characters were colored pink, and the rest were normal white.  A
single modified file at the top would also be colored pink.

Line buffering and full buffering are treated as the same thing in Windows [1],
meaning the stream is either buffered or not.  I can't find any explicit
documentation to say stdout is unbuffered by default when attached to a console
(but some internet postings indicated that is the case[2]).  Therefore, it seems
that explicit flushes are better than just not reopening stdout.

NB: pager is now on by default, and needs to be disabled to see any color on
Windows.

[1] https://msdn.microsoft.com/en-us/library/86cebhfs(v=vs.140).aspx
[2] https://sourceforge.net/p/mingw/mailman/message/27121137/

diff --git a/mercurial/color.py b/mercurial/color.py
--- a/mercurial/color.py
+++ b/mercurial/color.py
@@ -463,9 +463,11 @@
                 for sattr in m.group(1).split(';'):
                     if sattr:
                         attr = mapcolor(int(sattr), attr)
+                ui.flush()
                 _kernel32.SetConsoleTextAttribute(stdout, attr)
                 writefunc(m.group(2), **opts)
                 m = re.match(ansire, m.group(3))
         finally:
             # Explicitly reset original attributes
+            ui.flush()
             _kernel32.SetConsoleTextAttribute(stdout, origattr)


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