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

[Junio C Hamano <gitster@pobox.com>]

Jakub Narebski <jnareb@gmail.com> writes:

> On Tue, 17 July 2007, Matt McCutchen napisał:
> ...
>> Alert for gitweb site administrators: This patch changes the format of
>> $feature{'snapshot'}{'default'} in gitweb_config.perl from a list of
>> three pieces of information about a single format to a list of one or
>> more formats you wish to offer from the set ('tgz', 'tbz2', 'zip').
>> Update your gitweb_config.perl appropriately.  The preferred names for
>> gitweb.snapshot in repository configuration have also changed from
>> 'gzip' and 'bzip2' to 'tgz' and 'tbz2', but the old names are still
>> recognized for compatibility.
>
> This alert/warning should probably be put in RelNotes for when it would
> be in git.git

Does anybody else worry about the backward imcompatibility, I
wonder...  List?

I really hate to having to say something like that in the
RelNotes.  I do not think this is a good enough reason to break
existing configurations; I would not want to be defending that
change.

>> I thought of another incompatibility: previously bookmarked snapshot
>> URLs will no longer work because they lack the new "sf" parameter.  I
>> don't care about this; do any of you?
>
> I think either having good error message, or using first format avaiable
> would be good enough.

I doubt bookmarked snapshot URL would make sense to begin with,
so this would be Ok.

I am wondering if something like this patch (totally untested,
mind you) to convert the old style %feature in configuration at
the site at runtime would be sufficient.

diff --git a/gitweb/gitweb.perl b/gitweb/gitweb.perl
index f17c983..cdec4d0 100755
--- a/gitweb/gitweb.perl
+++ b/gitweb/gitweb.perl
@@ -236,9 +236,39 @@ our %feature = (
 		'default' => [0]},
 );
 
+# Functions to convert values from older gitweb configuration
+# into the current data format
+sub gitweb_bc_feature_snapshot {
+	my $def = $feature{'snapshot'}{'default'};
+	# Older definition was to have either undef (to disable), or
+	# a three-element array whose first element was content encoding
+	# without leading "application/".
+	return if (ref $def ne 'ARRAY');
+	if (!defined $def->[0] && @$def == 1) {
+		# Disabled -- the new way to spell it is to have an empty
+		# arrayref.
+		$feature{'snapshot'}{'default'} = [];
+		return;
+	}
+	return if (@$def != 3);
+	for ($def->[0]) {
+		if (/x-gzip/) {
+			$feature{'snapshot'}{'default'} = ['tgz'];
+		}
+		if (/x-bz2/) {
+			$feature{'snapshot'}{'default'} = ['tbz2'];
+		}
+		if (/x-zip/) {
+			$feature{'snapshot'}{'default'} = ['zip'];
+		}
+	}
+}
+
 sub gitweb_check_feature {
 	my ($name) = @_;
 	return unless exists $feature{$name};
+	eval "gitweb_bc_feature_$name()";
+
 	my ($sub, $override, @defaults) = (
 		$feature{$name}{'sub'},
 		$feature{$name}{'override'},