curses: do not setlocale() at import time (issue5261) stable

curses: do not setlocale() at import time (issue5261)

setlocale() can break date formatting/parsing functions because they are
locale dependent. We should avoid doing setlocale() as possible.

This patch moves setlocale() just before curses.wrapper(), which function
is documented to "initialize curses." I don't know the details about the
curses initialization, but I *think* this would work as well.

Maybe we can extract a curses setup function later.

https://www.mercurial-scm.org/pipermail/mercurial-devel/2019-February/128788.html

--- a/hgext/histedit.py	Mon Jul 22 19:10:59 2019 -0700
+++ b/hgext/histedit.py	Thu Jul 25 21:28:29 2019 +0900
@@ -201,6 +201,7 @@
     termios = None
 
 import functools
+import locale
 import os
 import struct
 
@@ -947,12 +948,6 @@
 # Curses Support
 try:
     import curses
-
-    # Curses requires setting the locale or it will default to the C
-    # locale. This sets the locale to the user's default system
-    # locale.
-    import locale
-    locale.setlocale(locale.LC_ALL, r'')
 except ImportError:
     curses = None
 
@@ -1538,6 +1533,10 @@
         ctxs = []
         for i, r in enumerate(revs):
             ctxs.append(histeditrule(repo[r], i))
+        # Curses requires setting the locale or it will default to the C
+        # locale. This sets the locale to the user's default system
+        # locale.
+        locale.setlocale(locale.LC_ALL, r'')
         rc = curses.wrapper(functools.partial(_chisteditmain, repo, ctxs))
         curses.echo()
         curses.endwin()
@@ -2323,4 +2322,3 @@
     cmdutil.summaryhooks.add('histedit', summaryhook)
     statemod.addunfinished('histedit', fname='histedit-state', allowcommit=True,
                             continueflag=True, abortfunc=hgaborthistedit)
-

--- a/mercurial/crecord.py	Mon Jul 22 19:10:59 2019 -0700
+++ b/mercurial/crecord.py	Thu Jul 25 21:28:29 2019 +0900
@@ -29,10 +29,6 @@
 )
 stringio = util.stringio
 
-# This is required for ncurses to display non-ASCII characters in default user
-# locale encoding correctly.  --immerrr
-locale.setlocale(locale.LC_ALL, r'')
-
 # patch comments based on the git one
 diffhelptext = _("""# To remove '-' lines, make them ' ' lines (context).
 # To remove '+' lines, delete them.
@@ -530,6 +526,9 @@
     """
     ui.write(_('starting interactive selection\n'))
     chunkselector = curseschunkselector(headerlist, ui, operation)
+    # This is required for ncurses to display non-ASCII characters in
+    # default user locale encoding correctly.  --immerrr
+    locale.setlocale(locale.LC_ALL, r'')
     origsigtstp = sentinel = object()
     if util.safehasattr(signal, 'SIGTSTP'):
         origsigtstp = signal.getsignal(signal.SIGTSTP)