--sendmail-command doesn't add common sendmail arguments to specified command
line tool. This fact is not documented and makes default Darcs behaviour useless.

I suggest appending default arguments to --sendmail-command if there are no
format specifiers present. There could be additional reference in cmd help to
the manual for format specifiers.

No, the point of the --sendmail-command feature is to allow the user to specify
how they want email sent.  If they have a program to send mail that doesn't want
any arguments, darcs shouldn't break that program by adding garbage arguments.

So this is a documentation bug.  Although, actually, this is pretty well
documented, so I'm not sure what your problem is.  Did you actually read the
documentation? It doesn't explicitly say "If you don't specify any flags, darcs
won't add them", but it does describe exactly what darcs does.

I see that our web page doesn't have links to the documentation...

No program is able to send email with changes from Darcs without arguments. At
least one argument with email body should always be specified.

If you say smb. to supply sendmail-command the majority of people assume this
command should work just like sendmail itself. With the same default command
line interface (i.e. accept list of recipients as arguments and read message
body from stdin).

Let me repeat - default arguments should be supplied only in case when no format
specifiers are present.

> No program is able to send email with changes from Darcs without arguments. At
> least one argument with email body should always be specified.

Maybe in practice, but it is conceivable that an email program just read
everything from stdin

> Let me repeat - default arguments should be supplied only in case when no format
> specifiers are present.

If what I'm saying above makes sense, then as David points out, this would break
such programs.

Perhaps you could submit a documentation patch that suggests a good set of
default arguments for people who just want to use something that behaves like
sendmail.  Or suggest it here, and I'll submit the patch.

Marking as wont-fix, but thanks for the idea!

Even if a message body is feed to stdin there are still recipients addresses
that should be specified for MTA. There is a good reference of sendmail
compatible interface at http://www.postfix.org/sendmail.1.html

At least it would be nice to have "sendmail [recipient ...]" part working, so
that people could plug any sendmail replacement that awaits recipient list in
cmdline and waits for message from stdin. Just plug without reading the docs and
configuring format specifiers.

You won't break anything, because programs that doesn't use command line
parameters won't use them. Programs that use command line parameter are all
already have configured custom format string for them. Default sendmail behavior
is assumed only when there is no custom format string specified.