Re: [PATCH] gitweb: snapshot cleanups & support for offering multiple formats

> > The advantage of '| gzip' is that the lack of a compressor is
> > not a special case.  This is why I wrote %known_snapshot_formats the
> > way I did, but of course you all are welcome to overrule me.
>
> I wrote about this because I'm thinking about replacing the few
> pipelines we use in gitweb[*1*], including the snapshot one, with
> the list form, which has the advantage of avoiding spawning the shell
> (performance) and not dealing with shell quoting of arguments (security
> and errors), like we did for simple calling of git commands to read
> from in the commit b9182987a80f7e820cbe1f8c7c4dc26f8586e8cd
>   "gitweb: Use list for of open for running git commands, thorougly"
>
> Thus I'd rather have list of extra commands and arguments instead of
> pipe as a string, i.e. 'gzip' instead of '| gzip', and 'gzip', '-9'
> instead of '| gzip -9'.
>
> [*1*] We currently use pipelines for snapshots which need external
> compressor, like tgz and tbz2, and for pickaxe search.

> I also prefer the second option, perhaps as simple as 'gzip' => 'tbz'
> and 'bzip2' => 'tbz2', and of course accompaning code to deal with this.
>
> As to "display name" column: I'm not sure if for example 'tar.gz'
> instead of 'tgz' would be not easier to understand.

> > It would be possible to make the gitweb site configuration
> > backward-compatible too; here's one possible approach.  On startup,
> > gitweb would check whether $feature{'snapshot'}{'default'} is a
> > three-element list that appears to be in the old format.  If so, it
> > would save the settings in $known_snapshot_formats{'default'} and then
> > set $feature{'snapshot'}{'default'} = 'default' .  This is a hack; is
> > it justified by the compatibility benefit?
>
> If you implement 'gzip' and 'bzip2' as aliases, it could be as simple
> as just taking last non-false element of array if the array has more
> than one element.