Polished exception handling when importing extensions: - Warning about failed import is printed on one line. - For this warning the [extensions] section key is used, because the value doesn't have to be set. - Whan a --traceback is requested, exit immediately to not mix up problems when importing an extension with other problems.

#!/bin/sh
#
mkdir t
cd t
hg init
echo 0 > a
echo 0 > b
hg ci -A -m m -d "1000000 0"
hg rm a
hg cat a
sleep 1 # make sure mtime is changed
echo 1 > b
hg ci -m m -d "1000000 0"
echo 2 > b
hg cat -r 0 a
hg cat -r 0 b
hg cat -r 1 a
hg cat -r 1 b