On 3/14/07, Junio C Hamano [off-list ref] wrote:
The --quiet option is silently turned off (but --exit-code is
still in effect, so is silent output) if postprocessing filters
such as pickaxe and diff-filter are used. For all practical
purposes I do not think of a reason to want to use these filters
and not viewing the diff output.
pickaxe filter can be useful in hooks to enforce policy
on use of some constructs. I can well imagine (do not
even have to imagine) a stupid company policy forbidding
commits with "\<printf\>" in them. Have no idea for
diff-filter though.