git-svn: enable --minimize to simplify the config and connections

--minimize will update the git-svn configuration to attempt to
connect to the repository root (instead of directly to the
path(s) we are tracking) in order to allow more efficient reuse
of connections (for multi-fetch and follow-parent).

Signed-off-by: Eric Wong <normalperson@yhbt.net>

diff --git a/git-svn.perl b/git-svn.perl
index 4084e06..15d65e2 100755 (executable)
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -119,8 +119,6 @@ my %cmd = (
                        \%fc_opts ],
        'migrate' => [ sub { },
                       # no-op, we automatically run this anyways,
-                      # we may add a flag to automatically optimize the
-                      # configuration to avoid reconnects in the future
                       'Migrate configuration/metadata/layout from
                        previous versions of git-svn',
                        \%remote_opts ],
@@ -158,6 +156,8 @@ my %opts = %{$cmd{$cmd}->[2]} if (defined $cmd);
 read_repo_config(\%opts);
 my $rv = GetOptions(%opts, 'help|H|h' => \$_help,
                                'version|V' => \$_version,
+                               'minimize-connections' =>
+                                 \$Git::SVN::Migration::_minimize,
                                'id|i=s' => \$Git::SVN::default_repo_id);
 exit 1 if (!$rv && $cmd ne 'log');
 
@@ -702,10 +702,22 @@ BEGIN {
                                        svn:entry:committed-date/;
 }
 
-# we allow dashes, unlike remotes2config.sh
+sub read_all_remotes {
+       my $r = {};
+       foreach (grep { s/^svn-remote\.// } command(qw/repo-config -l/)) {
+               if (m!^(.+)\.fetch=\s*(.*)\s*:\s*refs/remotes/(.+)\s*$!) {
+                       $r->{$1}->{fetch}->{$2} = $3;
+               } elsif (m!^(.+)\.url=\s*(.*)\s*$!) {
+                       $r->{$1}->{url} = $2;
+               }
+       }
+       $r;
+}
+
+# we allow more chars than remotes2config.sh...
 sub sanitize_remote_name {
        my ($name) = @_;
-       $name =~ tr/A-Za-z0-9-/./c;
+       $name =~ tr{A-Za-z0-9:,/+-}{.}c;
        $name;
 }
 
@@ -2467,7 +2479,8 @@ use strict;
 use warnings;
 use Carp qw/croak/;
 use File::Path qw/mkpath/;
-use File::Basename qw/dirname/;
+use File::Basename qw/dirname basename/;
+use vars qw/$_minimize/;
 
 sub migrate_from_v0 {
        my $git_dir = $ENV{GIT_DIR};
@@ -2577,16 +2590,101 @@ sub migrate_from_v2 {
        my $migrated = 0;
 
        foreach my $ref_id (sort keys %l_map) {
-               Git::SVN->init($l_map{$ref_id}, $ref_id);
+               Git::SVN->init($l_map{$ref_id}, '', $ref_id, $ref_id);
                $migrated++;
        }
        $migrated;
 }
 
+sub minimize_connections {
+       my $r = Git::SVN::read_all_remotes();
+       my $new_urls = {};
+       my $root_repos = {};
+       foreach my $repo_id (keys %$r) {
+               my $url = $r->{$repo_id}->{url} or next;
+               my $fetch = $r->{$repo_id}->{fetch} or next;
+               my $ra = Git::SVN::Ra->new($url);
+
+               # skip existing cases where we already connect to the root
+               if (($ra->{url} eq $ra->{repos_root}) ||
+                   (Git::SVN::sanitize_remote_name($ra->{repos_root}) eq
+                    $repo_id)) {
+                       $root_repos->{$ra->{url}} = $repo_id;
+                       next;
+               }
+
+               my $root_ra = Git::SVN::Ra->new($ra->{repos_root});
+               my $root_path = $ra->{url};
+               $root_path =~ s#^\Q$ra->{repos_root}\E/*##;
+               foreach my $path (keys %$fetch) {
+                       my $ref_id = $fetch->{$path};
+                       my $gs = Git::SVN->new($ref_id, $repo_id, $path);
+
+                       # make sure we can read when connecting to
+                       # a higher level of a repository
+                       my ($last_rev, undef) = $gs->last_rev_commit;
+                       if (!defined $last_rev) {
+                               $last_rev = eval {
+                                       $root_ra->get_latest_revnum;
+                               };
+                               next if $@;
+                       }
+                       my $new = $root_path;
+                       $new .= length $path ? "/$path" : '';
+                       eval {
+                               $root_ra->get_log([$new], $last_rev, $last_rev,
+                                                 0, 0, 1, sub { });
+                       };
+                       next if $@;
+                       $new_urls->{$ra->{repos_root}}->{$new} =
+                               { ref_id => $ref_id,
+                                 old_repo_id => $repo_id,
+                                 old_path => $path };
+               }
+       }
+
+       my @emptied;
+       foreach my $url (keys %$new_urls) {
+               # see if we can re-use an existing [svn-remote "repo_id"]
+               # instead of creating a(n ugly) new section:
+               my $repo_id = $root_repos->{$url} ||
+                             Git::SVN::sanitize_remote_name($url);
+
+               my $fetch = $new_urls->{$url};
+               foreach my $path (keys %$fetch) {
+                       my $x = $fetch->{$path};
+                       Git::SVN->init($url, $path, $repo_id, $x->{ref_id});
+                       my $pfx = "svn-remote.$x->{old_repo_id}";
+
+                       my $old_fetch = quotemeta("$x->{old_path}:".
+                                                 "refs/remotes/$x->{ref_id}");
+                       command_noisy(qw/repo-config --unset/,
+                                     "$pfx.fetch", '^'. $old_fetch . '$');
+                       delete $r->{$x->{old_repo_id}}->
+                              {fetch}->{$x->{old_path}};
+                       if (!keys %{$r->{$x->{old_repo_id}}->{fetch}}) {
+                               command_noisy(qw/repo-config --unset/,
+                                             "$pfx.url");
+                               push @emptied, $x->{old_repo_id}
+                       }
+               }
+       }
+       if (@emptied) {
+               my $file = $ENV{GIT_CONFIG} || $ENV{GIT_CONFIG_LOCAL} ||
+                          "$ENV{GIT_DIR}/config";
+               print STDERR <<EOF;
+The following [svn-remote] sections in your config file ($file) are empty
+and can be safely removed:
+EOF
+               print STDERR "[svn-remote \"$_\"]\n" foreach @emptied;
+       }
+}
+
 sub migration_check {
        migrate_from_v0();
        migrate_from_v1();
        migrate_from_v2();
+       minimize_connections() if $_minimize;
 }
 
 __END__

diff --git a/t/t9107-git-svn-migrate.sh b/t/t9107-git-svn-migrate.sh
index 53318f1..74a45ec 100755 (executable)
--- a/t/t9107-git-svn-migrate.sh
+++ b/t/t9107-git-svn-migrate.sh
@@ -46,6 +46,7 @@ test_expect_success 'initialize a multi-repository repo' "
        grep '^tags/0\.3:refs/remotes/tags/0\.3$' fetch.out
        "
 
+# refs should all be different, but the trees should all be the same:
 test_expect_success 'multi-fetch works on partial urls + paths' "
        git-svn multi-fetch &&
        for i in trunk a b tags/0.1 tags/0.2 tags/0.3; do
@@ -59,5 +60,29 @@ test_expect_success 'multi-fetch works on partial urls + paths' "
                                 refs/remotes/\$j\`\" ||exit 1; done; done
        "
 
+test_expect_success 'migrate --minimize on old multi-inited layout' "
+       git repo-config --unset-all svn-remote.git-svn.fetch &&
+       git repo-config --unset-all svn-remote.git-svn.url &&
+       rm -rf $GIT_DIR/svn &&
+       for i in \`cat fetch.out\`; do
+               path=\`expr \$i : '\\([^:]*\\):.*$'\`
+               ref=\`expr \$i : '[^:]*:refs/remotes/\\(.*\\)$'\`
+               if test -z \"\$ref\"; then continue; fi
+               if test -n \"\$path\"; then path=\"/\$path\"; fi
+               ( mkdir -p $GIT_DIR/svn/\$ref/info/ &&
+               echo $svnrepo\$path > $GIT_DIR/svn/\$ref/info/url ) || exit 1;
+       done &&
+       git-svn migrate --minimize &&
+       test -z \"\`git-repo-config -l |grep -v '^svn-remote\.git-svn\.'\`\" &&
+       git-repo-config --get-all svn-remote.git-svn.fetch > fetch.out &&
+       grep '^trunk:refs/remotes/trunk$' fetch.out &&
+       grep '^branches/a:refs/remotes/a$' fetch.out &&
+       grep '^branches/b:refs/remotes/b$' fetch.out &&
+       grep '^tags/0\.1:refs/remotes/tags/0\.1$' fetch.out &&
+       grep '^tags/0\.2:refs/remotes/tags/0\.2$' fetch.out &&
+       grep '^tags/0\.3:refs/remotes/tags/0\.3$' fetch.out
+       grep '^:refs/remotes/git-svn' fetch.out
+       "
+
 test_done