SVN import issue

Hi,

I'm off to the beach for the next two weeks, so if somebody wants to munge cvs2git into svn2git, here's the basics on how to pull from a remote SVN repo:

#!/usr/bin/perl

use strict; use warnings; use SVN::Core; use SVN::Ra;

my(@new,@del,@mod);
sub show_log {
	my ($changed_paths, $revision, $author, $date, $message, $pool) = @_;
	$author = '<unknown>' unless defined $author;
	@new = (); @del = (); @mod = ();

	(my $pmessage = $message) =~ s/\n/\n    /g;
	print "*** $revision: $author \@ $date:\n<<< $pmessage>>>\n";
	print "Files:\n";
	while(my($path,$action) = each %$changed_paths) {
		my $act = $action->action;
		my $oldpath = $action->copyfrom_path;
		my $oldrev = $action->copyfrom_rev;
		$oldrev = undef if defined $oldrev and $oldrev <= 0;
		$oldpath = undef if defined $oldpath and ($oldpath eq "" or $oldpath eq $path);
		print "$act $path";
		print " <-" if $oldpath or $oldrev;
		print " $oldpath" if defined $oldpath;
		print " $oldrev" if defined $oldrev;
		print "\n";
		if($act eq "A") {
			push(@new,$path);
		} elsif($act eq "D") {
			push(@del,$path);
		} else {
			push(@mod,$path);
		}
	}
}

my $ra = SVN::Ra->new("svn://cvs.gnupg.org/gnupg");

my $latest = $ra->get_latest_revnum();
my $n = 1;
while($n <= $latest) {
	$ra->get_log("/",$n,$n,$n,1,1,\&show_log,"");

	foreach my $path(@new,@mod) {
		print "Reading $path, $n...\n";
		open(F,">/tmp/foo"); # ( OK, so use tempfile() here ;-)
		eval {
			$ra->get_file($path,$n,\*F);
		};
		close(F);
		if ($@) {
			print "... not a file\n";
			next;
		}
		my $sz = (stat("/tmp/foo"))[7];
		print "... done, $sz bytes\n.";
	}
} continue {
	$n++;
}

Paths in SVN are usually prefixed "/trunk/" (main branch) or "/branches/foo/" (branch foo); tagging is done by creating "/tags/bar", with the trunk (or branch) revision it is pointing to as its parent.

So a branch point looks like this:

*** 350: <unknown> @ 1999-09-18T11:04:00.000000Z:
<<< This commit was manufactured by cvs2svn to create branch
    'STABLE-BRANCH-1-0'.>>>
Files:
A /branches/STABLE-BRANCH-1-0/cipher/rndw32.c <- /trunk/cipher/rndw32.c 349
A /branches/STABLE-BRANCH-1-0 <- /trunk 348

(and of *course* it may have changes from other revisions in it, anything else would simply be too easy I guess...). Tags look like they do, see tag 1-0-0 in the above repo; that seems to happen because their CVS importer couldn't find a sane branchpoint. cvsps reports the same thing.

I haven't yet examined what a SVN merge looks like.

Nothing stops a SVN check-in from touching multiple branches at the same time, though in practice that doesn't happen.

The mapping of SVN revision numbers to git SHA1s could get a bit annoying because incremental imports need to work. Personally I'd use a .svnmap file which has "svnid sha1" lines inside. The last line obviously would not have a sha1 because we can't know that before checking in the file...

So, if I find a working SVN importer when I come back I'll be happy ;-) (munging cvs2git shouldn't be particularly difficult), otherwise I'll do it myself, in a month or so.