Don't allow --style and --template for hg update and hg merge.
The only way that changesets will be shown with these command is in an error
message when trying to update to an ambiguous branch name.
#!/bin/sh
hg init
echo "Is there an error message when trying to diff non-existing files?"
hg diff not found
echo "Is there an error message when trying to add non-existing files?"
hg add not found