[Pkg-exim4-users] minor comment on exim README.Debian

[Marc Haber]

On Sat, Dec 10, 2005 at 05:13:33PM -0800, Ross Boylan wrote:
> On Sat, Dec 10, 2005 at 06:32:51PM -0500, Faheem Mitha wrote:
> > The README.Debian says
> > Benefits of the split configuration approach:
> >    * it means less work for you when upgrading. If we shipped one big file
> >      and modified for example the Maildir transport in a new version you
> >      won't have to do manual conffile merging unless you had changed
> >      exactly _this_ transport.
> >    * It allows other packages (e.g. sa-exim) to modify exim's
> >      configuration by shipping files in /etc/exim4/conf.d.
> > 
> > Benefits of the unsplit configuration approach:
> >    * It is more fragile. If I add optionfoo=bar to the Debian setup of
> >      a later version, and you have already set this option in a local
> >      file, exim will break with the new version until you manually
> >      correct this.
> > 
> > I think the latter paragraph is a little unclear. How is it a benefit that 
> > the unsplit configuration is more fragile?

That's an error in the docs which was fixed some time after sarge's
release. The sentence should mean "It is less fragile".

> I'm pretty sure the "It is more fragile" section describes the split
> configuration.  The benefit of unsplit is that it doesn't suffer this
> problem.

Agreed.

> I agree that the sections you quote are unclear.

I have re-worded the sections. What do you think about this:

        Benefits of the split configuration approach:
        <itemizedlist>
          <listitem>
            <simpara>
              it means less work for you when upgrading. If we shipped
              one big file and modified for example the Maildir
              transport in a new version you won't have to do manual
              conffile merging unless you had changed exactly
              <emphasis>this</emphasis> transport.
            </simpara>
          </listitem>
          <listitem>
            <simpara>
              It allows other packages (e.g. sa-exim) to modify exim's
              configuration by dropping files into
              <filename>/etc/exim4/conf.d</filename>. This needs, however
              quite exact syncing between the exim4 packages and the other,
              cooperating package.
            </simpara>
          </listitem>
          <listitem>
            <simpara>
              It is more fragile. If files from different sources
              (package, manually changed, or other package) get out of
              sync, it is possible for exim to break until you
              manually correct this. This can for example happen if we
              decide to add a new option to the Debian setup of a
              later version, and you have already set this option in a
              local file.
            </simpara>
          </listitem>
        </itemizedlist>
      </para>
      <para>
        Benefits of the unsplit configuration approach:
        <itemizedlist>
          <listitem>
            <simpara>
              People familiar with configuring exim may find this
              approach easier to understand as exim4.conf.template
              basically is a complete exim configuration file which will
              only undergo some basic string replacement before is it
              passed to exim.
            </simpara>
          </listitem>
          <listitem>
            <simpara>
              Split-config's fragility mentioned above does not occur
              with the unsplit configuration at the price of needing manual
              intervention in case of an upgrade.
            </simpara>
          </listitem>
        </itemizedlist>
      </para>
      <para>
        If in doubt go for the unsplit config, because it is easier to
        roll back to Debian's default configuration in one step. If you
        intend to do many changes to the Debian setup, you might want to
        use the split config at the price of having to more closely
        examine the config file after an update.
      </para>
      <para>
        We'd appreciate a patch that uses ucf and the 3-way-merge
        mechanism offered by that package. It might be the best way to
        handle the big configuration file.
      </para>

If you find that acceptable, I'll commit it to svn.

Greetings
Marc

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