[PATCH 1 of 2] crecord: add error reporting for failure in curses interface initialization

[Laurent Charignon]

# HG changeset patch
# User Laurent Charignon <lcharignon at fb.com>
# Date 1437165677 25200
#      Fri Jul 17 13:41:17 2015 -0700
# Node ID 67e626be03062910ce3b09c3ef56a1ed9c9ba802
# Parent  2748bf78a5bf610da4f2d90fd1eea19a3b360c04
crecord: add error reporting for failure in curses interface initialization

Before this patch, we couldn't report to the user any error that occurred:
- after we enabled the curses interface but
- before the interface is set up and drawn
This patch, provides a way to set errors that happens during the initialization
of the interface and log them once the curses interface has been displayed.

diff --git a/mercurial/crecord.py b/mercurial/crecord.py
--- a/mercurial/crecord.py
+++ b/mercurial/crecord.py
@@ -483,6 +483,8 @@ def chunkselector(ui, headerlist):
     ui.write(_('starting interactive selection\n'))
     chunkselector = curseschunkselector(headerlist, ui)
     curses.wrapper(chunkselector.main)
+    if chunkselector.initerr is not None:
+        raise util.Abort(chunkselector.initerr)
 
 def testdecorator(testfn, f):
     def u(*args, **kwargs):
@@ -1579,6 +1581,9 @@ are you sure you want to review/edit and
         """
         signal.signal(signal.SIGWINCH, self.sigwinchhandler)
         self.stdscr = stdscr
+        # error during initialization, cannot be printed in the curses
+        # interface, it should be printed by the calling code
+        self.initerr = None
         self.yscreensize, self.xscreensize = self.stdscr.getmaxyx()
 
         curses.start_color()