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

hg init a
cd a
echo bar > foo
hg add foo
hg ci -m 'add foo' -d '1000000 0'

echo foobar > foo
hg ci -m 'change foo' -d '1000001 0'

echo 'quiet:'
hg --quiet diff -r 0 -r 1
echo

echo 'normal:'
hg diff -r 0 -r 1
echo

echo 'verbose:'
hg --verbose diff -r 0 -r 1
echo

echo 'debug:'
hg --debug diff -r 0 -r 1
echo