Don't try to determine interactivity if ui() called with interactive=False. WSGI applications are not supposed to refer to sys.stdin. In ed6df6b1c29a, hgweb and hgwebdir were fixed to pass interactive=False to their ui()'s, but sys.stdin.isatty() was still called by the ui objects. This change makes sure only the ui.fixconfig() method will call ui.isatty() (by making the ui._readline() method, which is currently only called from ui.prompt(), private). ui.fixconfig() is changed to let config files override the initial interactivity setting, but not check isatty() if interactive=False was specified in the creation of the ui.

#!/bin/sh

echo % init foo-base
hg init foo-base

echo % create alpha in first repo
cd foo-base
echo 'alpha' > alpha
hg ci -A -m 'add alpha' -d '1 0'
cd ..

echo % clone foo-base to foo-work
hg clone foo-base foo-work

echo % create beta in second repo
cd foo-work
echo 'beta' > beta
hg ci -A -m 'add beta' -d '2 0'
cd ..

echo % create gamma in first repo
cd foo-base
echo 'gamma' > gamma
hg ci -A -m 'add gamma' -d '3 0'
cd ..

echo % pull into work and merge
cd foo-work
hg pull -q
hg merge

echo % revert to changeset 1 to simulate a failed merge
rm alpha beta gamma
hg up -C 1