Summary and Info:

There are two places could improve.

1. if no changeset, it will hang.
2. clone save space & speed

I wish it could be
hg incoming # but if no changeset here, it will quit
if [ $? -ne 0 ] ; then
hg pull -u
fi

Steps to Reproduce:

if [[ -d "$_hgrepo" ]]; then
cd "$_hgrepo"
hg pull -u || true # prevent error when no changeset
msg "The local files are updated."
else
hg clone "$_hgroot" "$_hgrepo"
fi

msg "Mercurial checkout done or server timeout"
msg "Starting build..."

rm -rf "$srcdir/$_hgrepo-build"
hg clone "$srcdir/$_hgrepo" "$srcdir/$_hgrepo-build" # clone save space & speed
cd "$srcdir/$_hgrepo-build/src"