perl/Git/SVN/Migration.pm

   1 package Git::SVN::Migration;
   2 # these version numbers do NOT correspond to actual version numbers
   3 # of git or 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         command_oneline
  48 );
  49 use Git::SVN;
  50
  51 sub migrate_from_v0 {
  52         my $git_dir = $ENV{GIT_DIR};
  53         return undef unless -d $git_dir;
  54         my ($fh, $ctx) = command_output_pipe(qw/rev-parse --symbolic --all/);
  55         my $migrated = 0;
  56         while (<$fh>) {
  57                 chomp;
  58                 my ($id, $orig_ref) = ($_, $_);
  59                 next unless $id =~ s#^refs/heads/(.+)-HEAD$#$1#;
  60                 my $info_url = command_oneline(qw(rev-parse --git-path),
  61                                                 "$id/info/url");
  62                 next unless -f $info_url;
  63                 my $new_ref = "refs/remotes/$id";
  64                 if (::verify_ref("$new_ref^0")) {
  65                         print STDERR "W: $orig_ref is probably an old ",
  66                                      "branch used by an ancient version of ",
  67                                      "git-svn.\n",
  68                                      "However, $new_ref also exists.\n",
  69                                      "We will not be able ",
  70                                      "to use this branch until this ",
  71                                      "ambiguity is resolved.\n";
  72                         next;
  73                 }
  74                 print STDERR "Migrating from v0 layout...\n" if !$migrated;
  75                 print STDERR "Renaming ref: $orig_ref => $new_ref\n";
  76                 command_noisy('update-ref', $new_ref, $orig_ref);
  77                 command_noisy('update-ref', '-d', $orig_ref, $orig_ref);
  78                 $migrated++;
  79         }
  80         command_close_pipe($fh, $ctx);
  81         print STDERR "Done migrating from v0 layout...\n" if $migrated;
  82         $migrated;
  83 }
  84
  85 sub migrate_from_v1 {
  86         my $git_dir = $ENV{GIT_DIR};
  87         my $migrated = 0;
  88         return $migrated unless -d $git_dir;
  89         my $svn_dir = Git::SVN::svn_dir();
  90
  91         # just in case somebody used 'svn' as their $id at some point...
  92         return $migrated if -d $svn_dir && ! -f "$svn_dir/info/url";
  93
  94         print STDERR "Migrating from a git-svn v1 layout...\n";
  95         mkpath([$svn_dir]);
  96         print STDERR "Data from a previous version of git-svn exists, but\n\t",
  97                      "$svn_dir\n\t(required for this version ",
  98                      "($::VERSION) of git-svn) does not exist.\n";
  99         my ($fh, $ctx) = command_output_pipe(qw/rev-parse --symbolic --all/);
 100         while (<$fh>) {
 101                 my $x = $_;
 102                 next unless $x =~ s#^refs/remotes/##;
 103                 chomp $x;
 104                 my $info_url = command_oneline(qw(rev-parse --git-path),
 105                                                 "$x/info/url");
 106                 next unless -f $info_url;
 107                 my $u = eval { ::file_to_s($info_url) };
 108                 next unless $u;
 109                 my $dn = dirname("$svn_dir/$x");
 110                 mkpath([$dn]) unless -d $dn;
 111                 if ($x eq 'svn') { # they used 'svn' as GIT_SVN_ID:
 112                         mkpath(["$svn_dir/svn"]);
 113                         print STDERR " - $git_dir/$x/info => ",
 114                                         "$svn_dir/$x/info\n";
 115                         rename "$git_dir/$x/info", "$svn_dir/$x/info" or
 116                                croak "$!: $x";
 117                         # don't worry too much about these, they probably
 118                         # don't exist with repos this old (save for index,
 119                         # and we can easily regenerate that)
 120                         foreach my $f (qw/unhandled.log index .rev_db/) {
 121                                 rename "$git_dir/$x/$f", "$svn_dir/$x/$f";
 122                         }
 123                 } else {
 124                         print STDERR " - $git_dir/$x => $svn_dir/$x\n";
 125                         rename "$git_dir/$x", "$svn_dir/$x" or croak "$!: $x";
 126                 }
 127                 $migrated++;
 128         }
 129         command_close_pipe($fh, $ctx);
 130         print STDERR "Done migrating from a git-svn v1 layout\n";
 131         $migrated;
 132 }
 133
 134 sub read_old_urls {
 135         my ($l_map, $pfx, $path) = @_;
 136         my @dir;
 137         foreach (<$path/*>) {
 138                 if (-r "$_/info/url") {
 139                         $pfx .= '/' if $pfx && $pfx !~ m!/$!;
 140                         my $ref_id = $pfx . basename $_;
 141                         my $url = ::file_to_s("$_/info/url");
 142                         $l_map->{$ref_id} = $url;
 143                 } elsif (-d $_) {
 144                         push @dir, $_;
 145                 }
 146         }
 147         my $svn_dir = Git::SVN::svn_dir();
 148         foreach (@dir) {
 149                 my $x = $_;
 150                 $x =~ s!^\Q$svn_dir\E/!!o;
 151                 read_old_urls($l_map, $x, $_);
 152         }
 153 }
 154
 155 sub migrate_from_v2 {
 156         my @cfg = command(qw/config -l/);
 157         return if grep /^svn-remote\..+\.url=/, @cfg;
 158         my %l_map;
 159         read_old_urls(\%l_map, '', Git::SVN::svn_dir());
 160         my $migrated = 0;
 161
 162         require Git::SVN;
 163         foreach my $ref_id (sort keys %l_map) {
 164                 eval { Git::SVN->init($l_map{$ref_id}, '', undef, $ref_id) };
 165                 if ($@) {
 166                         Git::SVN->init($l_map{$ref_id}, '', $ref_id, $ref_id);
 167                 }
 168                 $migrated++;
 169         }
 170         $migrated;
 171 }
 172
 173 sub minimize_connections {
 174         require Git::SVN;
 175         require Git::SVN::Ra;
 176
 177         my $r = Git::SVN::read_all_remotes();
 178         my $new_urls = {};
 179         my $root_repos = {};
 180         foreach my $repo_id (keys %$r) {
 181                 my $url = $r->{$repo_id}->{url} or next;
 182                 my $fetch = $r->{$repo_id}->{fetch} or next;
 183                 my $ra = Git::SVN::Ra->new($url);
 184
 185                 # skip existing cases where we already connect to the root
 186                 if (($ra->url eq $ra->{repos_root}) ||
 187                     ($ra->{repos_root} eq $repo_id)) {
 188                         $root_repos->{$ra->url} = $repo_id;
 189                         next;
 190                 }
 191
 192                 my $root_ra = Git::SVN::Ra->new($ra->{repos_root});
 193                 my $root_path = $ra->url;
 194                 $root_path =~ s#^\Q$ra->{repos_root}\E(/|$)##;
 195                 foreach my $path (keys %$fetch) {
 196                         my $ref_id = $fetch->{$path};
 197                         my $gs = Git::SVN->new($ref_id, $repo_id, $path);
 198
 199                         # make sure we can read when connecting to
 200                         # a higher level of a repository
 201                         my ($last_rev, undef) = $gs->last_rev_commit;
 202                         if (!defined $last_rev) {
 203                                 $last_rev = eval {
 204                                         $root_ra->get_latest_revnum;
 205                                 };
 206                                 next if $@;
 207                         }
 208                         my $new = $root_path;
 209                         $new .= length $path ? "/$path" : '';
 210                         eval {
 211                                 $root_ra->get_log([$new], $last_rev, $last_rev,
 212                                                   0, 0, 1, sub { });
 213                         };
 214                         next if $@;
 215                         $new_urls->{$ra->{repos_root}}->{$new} =
 216                                 { ref_id => $ref_id,
 217                                   old_repo_id => $repo_id,
 218                                   old_path => $path };
 219                 }
 220         }
 221
 222         my @emptied;
 223         foreach my $url (keys %$new_urls) {
 224                 # see if we can re-use an existing [svn-remote "repo_id"]
 225                 # instead of creating a(n ugly) new section:
 226                 my $repo_id = $root_repos->{$url} || $url;
 227
 228                 my $fetch = $new_urls->{$url};
 229                 foreach my $path (keys %$fetch) {
 230                         my $x = $fetch->{$path};
 231                         Git::SVN->init($url, $path, $repo_id, $x->{ref_id});
 232                         my $pfx = "svn-remote.$x->{old_repo_id}";
 233
 234                         my $old_fetch = quotemeta("$x->{old_path}:".
 235                                                   "$x->{ref_id}");
 236                         command_noisy(qw/config --unset/,
 237                                       "$pfx.fetch", '^'. $old_fetch . '$');
 238                         delete $r->{$x->{old_repo_id}}->
 239                                {fetch}->{$x->{old_path}};
 240                         if (!keys %{$r->{$x->{old_repo_id}}->{fetch}}) {
 241                                 command_noisy(qw/config --unset/,
 242                                               "$pfx.url");
 243                                 push @emptied, $x->{old_repo_id}
 244                         }
 245                 }
 246         }
 247         if (@emptied) {
 248                 my $file = $ENV{GIT_CONFIG} ||
 249                         command_oneline(qw(rev-parse --git-path config));
 250                 print STDERR <<EOF;
 251 The following [svn-remote] sections in your config file ($file) are empty
 252 and can be safely removed:
 253 EOF
 254                 print STDERR "[svn-remote \"$_\"]\n" foreach @emptied;
 255         }
 256 }
 257
 258 sub migration_check {
 259         migrate_from_v0();
 260         migrate_from_v1();
 261         migrate_from_v2();
 262         minimize_connections() if $_minimize;
 263 }
 264
 265 1;