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
cp $TESTDIR/binfile.bin .
hg add binfile.bin
hg ci -m 'add binfile.bin' -d '0 0'

echo >> binfile.bin
hg ci -m 'change binfile.bin' -d '0 0'

hg revert -r 0 binfile.bin
hg ci -m 'revert binfile.bin' -d '0 0'

echo % diff -r 0 -r 1
hg diff --nodates -r 0 -r 1

echo % diff -r 0 -r 2
hg diff --nodates -r 0 -r 2

echo % diff --git -r 0 -r 1
hg diff --git -r 0 -r 1

echo % diff --git -r 0 -r 2
hg diff --git -r 0 -r 2