perl/Git/SVN/Migration.pm

   1 package Git::SVN::Migration;
   2 # these version numbers do NOT correspond to actual version numbers
   3 # of git nor git-svn.  They are just relative.
   4 #
   5 # v0 layout: .git/$id/info/url, refs/heads/$id-HEAD
   6 #
   7 # v1 layout: .git/$id/info/url, refs/remotes/$id
   8 #
   9 # v2 layout: .git/svn/$id/info/url, refs/remotes/$id
  10 #
  11 # v3 layout: .git/svn/$id, refs/remotes/$id
  12 #            - info/url may remain for backwards compatibility
  13 #            - this is what we migrate up to this layout automatically,
  14 #            - this will be used by git svn init on single branches
  15 # v3.1 layout (auto migrated):
  16 #            - .rev_db => .rev_db.$UUID, .rev_db will remain as a symlink
  17 #              for backwards compatibility
  18 #
  19 # v4 layout: .git/svn/$repo_id/$id, refs/remotes/$repo_id/$id
  20 #            - this is only created for newly multi-init-ed
  21 #              repositories.  Similar in spirit to the
  22 #              --use-separate-remotes option in git-clone (now default)
  23 #            - we do not automatically migrate to this (following
  24 #              the example set by core git)
  25 #
  26 # v5 layout: .rev_db.$UUID => .rev_map.$UUID
  27 #            - newer, more-efficient format that uses 24-bytes per record
  28 #              with no filler space.
  29 #            - use xxd -c24 < .rev_map.$UUID to view and debug
  30 #            - This is a one-way migration, repositories updated to the
  31 #              new format will not be able to use old git-svn without
  32 #              rebuilding the .rev_db.  Rebuilding the rev_db is not
  33 #              possible if noMetadata or useSvmProps are set; but should
  34 #              be no problem for users that use the (sensible) defaults.
  35 use strict;
  36 use warnings;
  37 use Carp qw/croak/;
  38 use File::Path qw/mkpath/;
  39 use File::Basename qw/dirname basename/;
  40
  41 our $_minimize;
  42 use Git qw(
  43         command
  44         command_noisy
  45         command_output_pipe
  46         command_close_pipe
  47 );
  48
  49 sub migrate_from_v0 {
  50         my $git_dir = $ENV{GIT_DIR};
  51         return undef unless -d $git_dir;
  52         my ($fh, $ctx) = command_output_pipe(qw/rev-parse --symbolic --all/);
  53         my $migrated = 0;
  54         while (<$fh>) {
  55                 chomp;
  56                 my ($id, $orig_ref) = ($_, $_);
  57                 next unless $id =~ s#^refs/heads/(.+)-HEAD$#$1#;
  58                 next unless -f "$git_dir/$id/info/url";
  59                 my $new_ref = "refs/remotes/$id";
  60                 if (::verify_ref("$new_ref^0")) {
  61                         print STDERR "W: $orig_ref is probably an old ",
  62                                      "branch used by an ancient version of ",
  63                                      "git-svn.\n",
  64                                      "However, $new_ref also exists.\n",
  65                                      "We will not be able ",
  66                                      "to use this branch until this ",
  67                                      "ambiguity is resolved.\n";
  68                         next;
  69                 }
  70                 print STDERR "Migrating from v0 layout...\n" if !$migrated;
  71                 print STDERR "Renaming ref: $orig_ref => $new_ref\n";
  72                 command_noisy('update-ref', $new_ref, $orig_ref);
  73                 command_noisy('update-ref', '-d', $orig_ref, $orig_ref);
  74                 $migrated++;
  75         }
  76         command_close_pipe($fh, $ctx);
  77         print STDERR "Done migrating from v0 layout...\n" if $migrated;
  78         $migrated;
  79 }
  80
  81 sub migrate_from_v1 {
  82         my $git_dir = $ENV{GIT_DIR};
  83         my $migrated = 0;
  84         return $migrated unless -d $git_dir;
  85         my $svn_dir = "$git_dir/svn";
  86
  87         # just in case somebody used 'svn' as their $id at some point...
  88         return $migrated if -d $svn_dir && ! -f "$svn_dir/info/url";
  89
  90         print STDERR "Migrating from a git-svn v1 layout...\n";
  91         mkpath([$svn_dir]);
  92         print STDERR "Data from a previous version of git-svn exists, but\n\t",
  93                      "$svn_dir\n\t(required for this version ",
  94                      "($::VERSION) of git-svn) does not exist.\n";
  95         my ($fh, $ctx) = command_output_pipe(qw/rev-parse --symbolic --all/);
  96         while (<$fh>) {
  97                 my $x = $_;
  98                 next unless $x =~ s#^refs/remotes/##;
  99                 chomp $x;
 100                 next unless -f "$git_dir/$x/info/url";
 101                 my $u = eval { ::file_to_s("$git_dir/$x/info/url") };
 102                 next unless $u;
 103                 my $dn = dirname("$git_dir/svn/$x");
 104                 mkpath([$dn]) unless -d $dn;
 105                 if ($x eq 'svn') { # they used 'svn' as GIT_SVN_ID:
 106                         mkpath(["$git_dir/svn/svn"]);
 107                         print STDERR " - $git_dir/$x/info => ",
 108                                         "$git_dir/svn/$x/info\n";
 109                         rename "$git_dir/$x/info", "$git_dir/svn/$x/info" or
 110                                croak "$!: $x";
 111                         # don't worry too much about these, they probably
 112                         # don't exist with repos this old (save for index,
 113                         # and we can easily regenerate that)
 114                         foreach my $f (qw/unhandled.log index .rev_db/) {
 115                                 rename "$git_dir/$x/$f", "$git_dir/svn/$x/$f";
 116                         }
 117                 } else {
 118                         print STDERR " - $git_dir/$x => $git_dir/svn/$x\n";
 119                         rename "$git_dir/$x", "$git_dir/svn/$x" or
 120                                croak "$!: $x";
 121                 }
 122                 $migrated++;
 123         }
 124         command_close_pipe($fh, $ctx);
 125         print STDERR "Done migrating from a git-svn v1 layout\n";
 126         $migrated;
 127 }
 128
 129 sub read_old_urls {
 130         my ($l_map, $pfx, $path) = @_;
 131         my @dir;
 132         foreach (<$path/*>) {
 133                 if (-r "$_/info/url") {
 134                         $pfx .= '/' if $pfx && $pfx !~ m!/$!;
 135                         my $ref_id = $pfx . basename $_;
 136                         my $url = ::file_to_s("$_/info/url");
 137                         $l_map->{$ref_id} = $url;
 138                 } elsif (-d $_) {
 139                         push @dir, $_;
 140                 }
 141         }
 142         foreach (@dir) {
 143                 my $x = $_;
 144                 $x =~ s!^\Q$ENV{GIT_DIR}\E/svn/!!o;
 145                 read_old_urls($l_map, $x, $_);
 146         }
 147 }
 148
 149 sub migrate_from_v2 {
 150         my @cfg = command(qw/config -l/);
 151         return if grep /^svn-remote\..+\.url=/, @cfg;
 152         my %l_map;
 153         read_old_urls(\%l_map, '', "$ENV{GIT_DIR}/svn");
 154         my $migrated = 0;
 155
 156         require Git::SVN;
 157         foreach my $ref_id (sort keys %l_map) {
 158                 eval { Git::SVN->init($l_map{$ref_id}, '', undef, $ref_id) };
 159                 if ($@) {
 160                         Git::SVN->init($l_map{$ref_id}, '', $ref_id, $ref_id);
 161                 }
 162                 $migrated++;
 163         }
 164         $migrated;
 165 }
 166
 167 sub minimize_connections {
 168         require Git::SVN;
 169         require Git::SVN::Ra;
 170
 171         my $r = Git::SVN::read_all_remotes();
 172         my $new_urls = {};
 173         my $root_repos = {};
 174         foreach my $repo_id (keys %$r) {
 175                 my $url = $r->{$repo_id}->{url} or next;
 176                 my $fetch = $r->{$repo_id}->{fetch} or next;
 177                 my $ra = Git::SVN::Ra->new($url);
 178
 179                 # skip existing cases where we already connect to the root
 180                 if (($ra->{url} eq $ra->{repos_root}) ||
 181                     ($ra->{repos_root} eq $repo_id)) {
 182                         $root_repos->{$ra->{url}} = $repo_id;
 183                         next;
 184                 }
 185
 186                 my $root_ra = Git::SVN::Ra->new($ra->{repos_root});
 187                 my $root_path = $ra->{url};
 188                 $root_path =~ s#^\Q$ra->{repos_root}\E(/|$)##;
 189                 foreach my $path (keys %$fetch) {
 190                         my $ref_id = $fetch->{$path};
 191                         my $gs = Git::SVN->new($ref_id, $repo_id, $path);
 192
 193                         # make sure we can read when connecting to
 194                         # a higher level of a repository
 195                         my ($last_rev, undef) = $gs->last_rev_commit;
 196                         if (!defined $last_rev) {
 197                                 $last_rev = eval {
 198                                         $root_ra->get_latest_revnum;
 199                                 };
 200                                 next if $@;
 201                         }
 202                         my $new = $root_path;
 203                         $new .= length $path ? "/$path" : '';
 204                         eval {
 205                                 $root_ra->get_log([$new], $last_rev, $last_rev,
 206                                                   0, 0, 1, sub { });
 207                         };
 208                         next if $@;
 209                         $new_urls->{$ra->{repos_root}}->{$new} =
 210                                 { ref_id => $ref_id,
 211                                   old_repo_id => $repo_id,
 212                                   old_path => $path };
 213                 }
 214         }
 215
 216         my @emptied;
 217         foreach my $url (keys %$new_urls) {
 218                 # see if we can re-use an existing [svn-remote "repo_id"]
 219                 # instead of creating a(n ugly) new section:
 220                 my $repo_id = $root_repos->{$url} || $url;
 221
 222                 my $fetch = $new_urls->{$url};
 223                 foreach my $path (keys %$fetch) {
 224                         my $x = $fetch->{$path};
 225                         Git::SVN->init($url, $path, $repo_id, $x->{ref_id});
 226                         my $pfx = "svn-remote.$x->{old_repo_id}";
 227
 228                         my $old_fetch = quotemeta("$x->{old_path}:".
 229                                                   "$x->{ref_id}");
 230                         command_noisy(qw/config --unset/,
 231                                       "$pfx.fetch", '^'. $old_fetch . '$');
 232                         delete $r->{$x->{old_repo_id}}->
 233                                {fetch}->{$x->{old_path}};
 234                         if (!keys %{$r->{$x->{old_repo_id}}->{fetch}}) {
 235                                 command_noisy(qw/config --unset/,
 236                                               "$pfx.url");
 237                                 push @emptied, $x->{old_repo_id}
 238                         }
 239                 }
 240         }
 241         if (@emptied) {
 242                 my $file = $ENV{GIT_CONFIG} || "$ENV{GIT_DIR}/config";
 243                 print STDERR <<EOF;
 244 The following [svn-remote] sections in your config file ($file) are empty
 245 and can be safely removed:
 246 EOF
 247                 print STDERR "[svn-remote \"$_\"]\n" foreach @emptied;
 248         }
 249 }
 250
 251 sub migration_check {
 252         migrate_from_v0();
 253         migrate_from_v1();
 254         migrate_from_v2();
 255         minimize_connections() if $_minimize;
 256 }
 257
 258 1;