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 rep; cd rep
touch empty-file
python -c 'for x in range(10000): print x' > large-file
hg addremove
hg commit -m A
rm large-file empty-file
python -c 'for x in range(10,10000): print x' > another-file
hg addremove -s50
hg commit -m B
echo % comparing two empty files caused ZeroDivisionError in the past
hg update -C 0
rm empty-file
touch another-empty-file
hg addremove -s50
cd ..
hg init rep2; cd rep2
python -c 'for x in range(10000): print x' > large-file
python -c 'for x in range(50): print x' > tiny-file
hg addremove
hg commit -m A
python -c 'for x in range(70): print x' > small-file
rm tiny-file
rm large-file
hg addremove -s50
hg commit -m B
echo % should all fail
hg addremove -s foo
hg addremove -s -1
hg addremove -s 1e6
true