#!/usr/bin/perl
# Copyright (C) 2006, Eric Wong <normalperson@yhbt.net>
# License: GPL v2 or later
use 5.008;
use warnings;
use strict;
use vars qw/    $AUTHOR $VERSION
                $sha1 $sha1_short $_revision $_repository
                $_q $_authors $_authors_prog %users/;
$AUTHOR = 'Eric Wong <normalperson@yhbt.net>';
$VERSION = '@@GIT_VERSION@@';

use Carp qw/croak/;
use Digest::MD5;
use IO::File qw//;
use File::Basename qw/dirname basename/;
use File::Path qw/mkpath/;
use File::Spec;
use File::Find;
use Getopt::Long qw/:config gnu_getopt no_ignore_case auto_abbrev/;
use IPC::Open3;
use Memoize;

use Git::SVN;
use Git::SVN::Editor;
use Git::SVN::Fetcher;
use Git::SVN::Ra;
use Git::SVN::Prompt;
use Git::SVN::Log;
use Git::SVN::Migration;

use Git::SVN::Utils qw(fatal can_compress);
use Git qw(
        git_cmd_try
        command
        command_oneline
        command_noisy
        command_output_pipe
        command_close_pipe
        command_bidi_pipe
        command_close_bidi_pipe
);

BEGIN {
        Memoize::memoize 'Git::config';
        Memoize::memoize 'Git::config_bool';
}


# From which subdir have we been invoked?
my $cmd_dir_prefix = eval {
        command_oneline([qw/rev-parse --show-prefix/], STDERR => 0)
} || '';

my $git_dir_user_set = 1 if defined $ENV{GIT_DIR};
$ENV{GIT_DIR} ||= '.git';
$Git::SVN::Ra::_log_window_size = 100;

if (! exists $ENV{SVN_SSH} && exists $ENV{GIT_SSH}) {
        $ENV{SVN_SSH} = $ENV{GIT_SSH};
}

if (exists $ENV{SVN_SSH} && $^O eq 'msys') {
        $ENV{SVN_SSH} =~ s/\\/\\\\/g;
        $ENV{SVN_SSH} =~ s/(.*)/"$1"/;
}

$Git::SVN::Log::TZ = $ENV{TZ};
$ENV{TZ} = 'UTC';
$| = 1; # unbuffer STDOUT

# All SVN commands do it.  Otherwise we may die on SIGPIPE when the remote
# repository decides to close the connection which we expect to be kept alive.
$SIG{PIPE} = 'IGNORE';

# Given a dot separated version number, "subtract" it from
# the SVN::Core::VERSION; non-negaitive return means the SVN::Core
# is at least at the version the caller asked for.
sub compare_svn_version {
        my (@ours) = split(/\./, $SVN::Core::VERSION);
        my (@theirs) = split(/\./, $_[0]);
        my ($i, $diff);

        for ($i = 0; $i < @ours && $i < @theirs; $i++) {
                $diff = $ours[$i] - $theirs[$i];
                return $diff if ($diff);
        }
        return 1 if ($i < @ours);
        return -1 if ($i < @theirs);
        return 0;
}

sub _req_svn {
        require SVN::Core; # use()-ing this causes segfaults for me... *shrug*
        require SVN::Ra;
        require SVN::Delta;
        if (::compare_svn_version('1.1.0') < 0) {
                fatal "Need SVN::Core 1.1.0 or better (got $SVN::Core::VERSION)";
        }
}

$sha1 = qr/[a-f\d]{40}/;
$sha1_short = qr/[a-f\d]{4,40}/;
my ($_stdin, $_help, $_edit,
        $_message, $_file, $_branch_dest,
        $_template, $_shared,
        $_version, $_fetch_all, $_no_rebase, $_fetch_parent,
        $_merge, $_strategy, $_preserve_merges, $_dry_run, $_local,
        $_prefix, $_no_checkout, $_url, $_verbose,
        $_commit_url, $_tag, $_merge_info, $_interactive);

# This is a refactoring artifact so Git::SVN can get at this git-svn switch.
sub opt_prefix { return $_prefix || '' }

$Git::SVN::Fetcher::_placeholder_filename = ".gitignore";
$_q ||= 0;
my %remote_opts = ( 'username=s' => \$Git::SVN::Prompt::_username,
                    'config-dir=s' => \$Git::SVN::Ra::config_dir,
                    'no-auth-cache' => \$Git::SVN::Prompt::_no_auth_cache,
                    'ignore-paths=s' => \$Git::SVN::Fetcher::_ignore_regex,
                    'ignore-refs=s' => \$Git::SVN::Ra::_ignore_refs_regex );
my %fc_opts = ( 'follow-parent|follow!' => \$Git::SVN::_follow_parent,
                'authors-file|A=s' => \$_authors,
                'authors-prog=s' => \$_authors_prog,
                'repack:i' => \$Git::SVN::_repack,
                'noMetadata' => \$Git::SVN::_no_metadata,
                'useSvmProps' => \$Git::SVN::_use_svm_props,
                'useSvnsyncProps' => \$Git::SVN::_use_svnsync_props,
                'log-window-size=i' => \$Git::SVN::Ra::_log_window_size,
                'no-checkout' => \$_no_checkout,
                'quiet|q+' => \$_q,
                'repack-flags|repack-args|repack-opts=s' =>
                   \$Git::SVN::_repack_flags,
                'use-log-author' => \$Git::SVN::_use_log_author,
                'add-author-from' => \$Git::SVN::_add_author_from,
                'localtime' => \$Git::SVN::_localtime,
                %remote_opts );

my ($_trunk, @_tags, @_branches, $_stdlayout);
my %icv;
my %init_opts = ( 'template=s' => \$_template, 'shared:s' => \$_shared,
                  'trunk|T=s' => \$_trunk, 'tags|t=s@' => \@_tags,
                  'branches|b=s@' => \@_branches, 'prefix=s' => \$_prefix,
                  'stdlayout|s' => \$_stdlayout,
                  'minimize-url|m!' => \$Git::SVN::_minimize_url,
                  'no-metadata' => sub { $icv{noMetadata} = 1 },
                  'use-svm-props' => sub { $icv{useSvmProps} = 1 },
                  'use-svnsync-props' => sub { $icv{useSvnsyncProps} = 1 },
                  'rewrite-root=s' => sub { $icv{rewriteRoot} = $_[1] },
                  'rewrite-uuid=s' => sub { $icv{rewriteUUID} = $_[1] },
                  %remote_opts );
my %cmt_opts = ( 'edit|e' => \$_edit,
                'rmdir' => \$Git::SVN::Editor::_rmdir,
                'find-copies-harder' => \$Git::SVN::Editor::_find_copies_harder,
                'l=i' => \$Git::SVN::Editor::_rename_limit,
                'copy-similarity|C=i'=> \$Git::SVN::Editor::_cp_similarity
);

my %cmd = (
        fetch => [ \&cmd_fetch, "Download new revisions from SVN",
                        { 'revision|r=s' => \$_revision,
                          'fetch-all|all' => \$_fetch_all,
                          'parent|p' => \$_fetch_parent,
                           %fc_opts } ],
        clone => [ \&cmd_clone, "Initialize and fetch revisions",
                        { 'revision|r=s' => \$_revision,
                          'preserve-empty-dirs' =>
                                \$Git::SVN::Fetcher::_preserve_empty_dirs,
                          'placeholder-filename=s' =>
                                \$Git::SVN::Fetcher::_placeholder_filename,
                           %fc_opts, %init_opts } ],
        init => [ \&cmd_init, "Initialize a repo for tracking" .
                          " (requires URL argument)",
                          \%init_opts ],
        'multi-init' => [ \&cmd_multi_init,
                          "Deprecated alias for ".
                          "'$0 init -T<trunk> -b<branches> -t<tags>'",
                          \%init_opts ],
        dcommit => [ \&cmd_dcommit,
                     'Commit several diffs to merge with upstream',
                        { 'merge|m|M' => \$_merge,
                          'strategy|s=s' => \$_strategy,
                          'verbose|v' => \$_verbose,
                          'dry-run|n' => \$_dry_run,
                          'fetch-all|all' => \$_fetch_all,
                          'commit-url=s' => \$_commit_url,
                          'revision|r=i' => \$_revision,
                          'no-rebase' => \$_no_rebase,
                          'mergeinfo=s' => \$_merge_info,
                          'interactive|i' => \$_interactive,
                        %cmt_opts, %fc_opts } ],
        branch => [ \&cmd_branch,
                    'Create a branch in the SVN repository',
                    { 'message|m=s' => \$_message,
                      'destination|d=s' => \$_branch_dest,
                      'dry-run|n' => \$_dry_run,
                      'tag|t' => \$_tag,
                      'username=s' => \$Git::SVN::Prompt::_username,
                      'commit-url=s' => \$_commit_url } ],
        tag => [ sub { $_tag = 1; cmd_branch(@_) },
                 'Create a tag in the SVN repository',
                 { 'message|m=s' => \$_message,
                   'destination|d=s' => \$_branch_dest,
                   'dry-run|n' => \$_dry_run,
                   'username=s' => \$Git::SVN::Prompt::_username,
                   'commit-url=s' => \$_commit_url } ],
        'set-tree' => [ \&cmd_set_tree,
                        "Set an SVN repository to a git tree-ish",
                        { 'stdin' => \$_stdin, %cmt_opts, %fc_opts, } ],
        'create-ignore' => [ \&cmd_create_ignore,
                             'Create a .gitignore per svn:ignore',
                             { 'revision|r=i' => \$_revision
                             } ],
        'mkdirs' => [ \&cmd_mkdirs ,
                      "recreate empty directories after a checkout",
                      { 'revision|r=i' => \$_revision } ],
        'propget' => [ \&cmd_propget,
                       'Print the value of a property on a file or directory',
                       { 'revision|r=i' => \$_revision } ],
        'proplist' => [ \&cmd_proplist,
                       'List all properties of a file or directory',
                       { 'revision|r=i' => \$_revision } ],
        'show-ignore' => [ \&cmd_show_ignore, "Show svn:ignore listings",
                        { 'revision|r=i' => \$_revision
                        } ],
        'show-externals' => [ \&cmd_show_externals, "Show svn:externals listings",
                        { 'revision|r=i' => \$_revision
                        } ],
        'multi-fetch' => [ \&cmd_multi_fetch,
                           "Deprecated alias for $0 fetch --all",
                           { 'revision|r=s' => \$_revision, %fc_opts } ],
        'migrate' => [ sub { },
                       # no-op, we automatically run this anyways,
                       'Migrate configuration/metadata/layout from
                        previous versions of git-svn',
                       { 'minimize' => \$Git::SVN::Migration::_minimize,
                         %remote_opts } ],
        'log' => [ \&Git::SVN::Log::cmd_show_log, 'Show commit logs',
                        { 'limit=i' => \$Git::SVN::Log::limit,
                          'revision|r=s' => \$_revision,
                          'verbose|v' => \$Git::SVN::Log::verbose,
                          'incremental' => \$Git::SVN::Log::incremental,
                          'oneline' => \$Git::SVN::Log::oneline,
                          'show-commit' => \$Git::SVN::Log::show_commit,
                          'non-recursive' => \$Git::SVN::Log::non_recursive,
                          'authors-file|A=s' => \$_authors,
                          'color' => \$Git::SVN::Log::color,
                          'pager=s' => \$Git::SVN::Log::pager
                        } ],
        'find-rev' => [ \&cmd_find_rev,
                        "Translate between SVN revision numbers and tree-ish",
                        {} ],
        'rebase' => [ \&cmd_rebase, "Fetch and rebase your working directory",
                        { 'merge|m|M' => \$_merge,
                          'verbose|v' => \$_verbose,
                          'strategy|s=s' => \$_strategy,
                          'local|l' => \$_local,
                          'fetch-all|all' => \$_fetch_all,
                          'dry-run|n' => \$_dry_run,
                          'preserve-merges|p' => \$_preserve_merges,
                          %fc_opts } ],
        'commit-diff' => [ \&cmd_commit_diff,
                           'Commit a diff between two trees',
                        { 'message|m=s' => \$_message,
                          'file|F=s' => \$_file,
                          'revision|r=s' => \$_revision,
                        %cmt_opts } ],
        'info' => [ \&cmd_info,
                    "Show info about the latest SVN revision
                     on the current branch",
                    { 'url' => \$_url, } ],
        'blame' => [ \&Git::SVN::Log::cmd_blame,
                    "Show what revision and author last modified each line of a file",
                    { 'git-format' => \$Git::SVN::Log::_git_format } ],
        'reset' => [ \&cmd_reset,
                     "Undo fetches back to the specified SVN revision",
                     { 'revision|r=s' => \$_revision,
                       'parent|p' => \$_fetch_parent } ],
        'gc' => [ \&cmd_gc,
                  "Compress unhandled.log files in .git/svn and remove " .
                  "index files in .git/svn",
                {} ],
);

use Term::ReadLine;
package FakeTerm;
sub new {
        my ($class, $reason) = @_;
        return bless \$reason, shift;
}
sub readline {
        my $self = shift;
        die "Cannot use readline on FakeTerm: $$self";
}
package main;

my $term = eval {
        $ENV{"GIT_SVN_NOTTY"}
                ? new Term::ReadLine 'git-svn', \*STDIN, \*STDOUT
                : new Term::ReadLine 'git-svn';
};
if ($@) {
        $term = new FakeTerm "$@: going non-interactive";
}

my $cmd;
for (my $i = 0; $i < @ARGV; $i++) {
        if (defined $cmd{$ARGV[$i]}) {
                $cmd = $ARGV[$i];
                splice @ARGV, $i, 1;
                last;
        } elsif ($ARGV[$i] eq 'help') {
                $cmd = $ARGV[$i+1];
                usage(0);
        }
};

# make sure we're always running at the top-level working directory
unless ($cmd && $cmd =~ /(?:clone|init|multi-init)$/) {
        unless (-d $ENV{GIT_DIR}) {
                if ($git_dir_user_set) {
                        die "GIT_DIR=$ENV{GIT_DIR} explicitly set, ",
                            "but it is not a directory\n";
                }
                my $git_dir = delete $ENV{GIT_DIR};
                my $cdup = undef;
                git_cmd_try {
                        $cdup = command_oneline(qw/rev-parse --show-cdup/);
                        $git_dir = '.' unless ($cdup);
                        chomp $cdup if ($cdup);
                        $cdup = "." unless ($cdup && length $cdup);
                } "Already at toplevel, but $git_dir not found\n";
                chdir $cdup or die "Unable to chdir up to '$cdup'\n";
                unless (-d $git_dir) {
                        die "$git_dir still not found after going to ",
                            "'$cdup'\n";
                }
                $ENV{GIT_DIR} = $git_dir;
        }
        $_repository = Git->repository(Repository => $ENV{GIT_DIR});
}

my %opts = %{$cmd{$cmd}->[2]} if (defined $cmd);

read_git_config(\%opts);
if ($cmd && ($cmd eq 'log' || $cmd eq 'blame')) {
        Getopt::Long::Configure('pass_through');
}
my $rv = GetOptions(%opts, 'h|H' => \$_help, 'version|V' => \$_version,
                    'minimize-connections' => \$Git::SVN::Migration::_minimize,
                    'id|i=s' => \$Git::SVN::default_ref_id,
                    'svn-remote|remote|R=s' => sub {
                       $Git::SVN::no_reuse_existing = 1;
                       $Git::SVN::default_repo_id = $_[1] });
exit 1 if (!$rv && $cmd && $cmd ne 'log');

usage(0) if $_help;
version() if $_version;
usage(1) unless defined $cmd;
load_authors() if $_authors;
if (defined $_authors_prog) {
        $_authors_prog = "'" . File::Spec->rel2abs($_authors_prog) . "'";
}

unless ($cmd =~ /^(?:clone|init|multi-init|commit-diff)$/) {
        Git::SVN::Migration::migration_check();
}
Git::SVN::init_vars();
eval {
        Git::SVN::verify_remotes_sanity();
        $cmd{$cmd}->[0]->(@ARGV);
        post_fetch_checkout();
};
fatal $@ if $@;
exit 0;

####################### primary functions ######################
sub usage {
        my $exit = shift || 0;
        my $fd = $exit ? \*STDERR : \*STDOUT;
        print $fd <<"";
git-svn - bidirectional operations between a single Subversion tree and git
Usage: git svn <command> [options] [arguments]\n

        print $fd "Available commands:\n" unless $cmd;

        foreach (sort keys %cmd) {
                next if $cmd && $cmd ne $_;
                next if /^multi-/; # don't show deprecated commands
                print $fd '  ',pack('A17',$_),$cmd{$_}->[1],"\n";
                foreach (sort keys %{$cmd{$_}->[2]}) {
                        # mixed-case options are for .git/config only
                        next if /[A-Z]/ && /^[a-z]+$/i;
                        # prints out arguments as they should be passed:
                        my $x = s#[:=]s$## ? '<arg>' : s#[:=]i$## ? '<num>' : '';
                        print $fd ' ' x 21, join(', ', map { length $_ > 1 ?
                                                        "--$_" : "-$_" }
                                                split /\|/,$_)," $x\n";
                }
        }
        print $fd <<"";
\nGIT_SVN_ID may be set in the environment or via the --id/-i switch to an
arbitrary identifier if you're tracking multiple SVN branches/repositories in
one git repository and want to keep them separate.  See git-svn(1) for more
information.

        exit $exit;
}

sub version {
        ::_req_svn();
        print "git-svn version $VERSION (svn $SVN::Core::VERSION)\n";
        exit 0;
}

sub ask {
        my ($prompt, %arg) = @_;
        my $valid_re = $arg{valid_re};
        my $default = $arg{default};
        my $resp;
        my $i = 0;

        if ( !( defined($term->IN)
            && defined( fileno($term->IN) )
            && defined( $term->OUT )
            && defined( fileno($term->OUT) ) ) ){
                return defined($default) ? $default : undef;
        }

        while ($i++ < 10) {
                $resp = $term->readline($prompt);
                if (!defined $resp) { # EOF
                        print "\n";
                        return defined $default ? $default : undef;
                }
                if ($resp eq '' and defined $default) {
                        return $default;
                }
                if (!defined $valid_re or $resp =~ /$valid_re/) {
                        return $resp;
                }
        }
        return undef;
}

sub do_git_init_db {
        unless (-d $ENV{GIT_DIR}) {
                my @init_db = ('init');
                push @init_db, "--template=$_template" if defined $_template;
                if (defined $_shared) {
                        if ($_shared =~ /[a-z]/) {
                                push @init_db, "--shared=$_shared";
                        } else {
                                push @init_db, "--shared";
                        }
                }
                command_noisy(@init_db);
                $_repository = Git->repository(Repository => ".git");
        }
        my $set;
        my $pfx = "svn-remote.$Git::SVN::default_repo_id";
        foreach my $i (keys %icv) {
                die "'$set' and '$i' cannot both be set\n" if $set;
                next unless defined $icv{$i};
                command_noisy('config', "$pfx.$i", $icv{$i});
                $set = $i;
        }
        my $ignore_paths_regex = \$Git::SVN::Fetcher::_ignore_regex;
        command_noisy('config', "$pfx.ignore-paths", $$ignore_paths_regex)
                if defined $$ignore_paths_regex;
        my $ignore_refs_regex = \$Git::SVN::Ra::_ignore_refs_regex;
        command_noisy('config', "$pfx.ignore-refs", $$ignore_refs_regex)
                if defined $$ignore_refs_regex;

        if (defined $Git::SVN::Fetcher::_preserve_empty_dirs) {
                my $fname = \$Git::SVN::Fetcher::_placeholder_filename;
                command_noisy('config', "$pfx.preserve-empty-dirs", 'true');
                command_noisy('config', "$pfx.placeholder-filename", $$fname);
        }
}

sub init_subdir {
        my $repo_path = shift or return;
        mkpath([$repo_path]) unless -d $repo_path;
        chdir $repo_path or die "Couldn't chdir to $repo_path: $!\n";
        $ENV{GIT_DIR} = '.git';
        $_repository = Git->repository(Repository => $ENV{GIT_DIR});
}

sub cmd_clone {
        my ($url, $path) = @_;
        if (!defined $path &&
            (defined $_trunk || @_branches || @_tags ||
             defined $_stdlayout) &&
            $url !~ m#^[a-z\+]+://#) {
                $path = $url;
        }
        $path = basename($url) if !defined $path || !length $path;
        my $authors_absolute = $_authors ? File::Spec->rel2abs($_authors) : "";
        cmd_init($url, $path);
        command_oneline('config', 'svn.authorsfile', $authors_absolute)
            if $_authors;
        Git::SVN::fetch_all($Git::SVN::default_repo_id);
}

sub cmd_init {
        if (defined $_stdlayout) {
                $_trunk = 'trunk' if (!defined $_trunk);
                @_tags = 'tags' if (! @_tags);
                @_branches = 'branches' if (! @_branches);
        }
        if (defined $_trunk || @_branches || @_tags) {
                return cmd_multi_init(@_);
        }
        my $url = shift or die "SVN repository location required ",
                               "as a command-line argument\n";
        $url = canonicalize_url($url);
        init_subdir(@_);
        do_git_init_db();

        if ($Git::SVN::_minimize_url eq 'unset') {
                $Git::SVN::_minimize_url = 0;
        }

        Git::SVN->init($url);
}

sub cmd_fetch {
        if (grep /^\d+=./, @_) {
                die "'<rev>=<commit>' fetch arguments are ",
                    "no longer supported.\n";
        }
        my ($remote) = @_;
        if (@_ > 1) {
                die "Usage: $0 fetch [--all] [--parent] [svn-remote]\n";
        }
        $Git::SVN::no_reuse_existing = undef;
        if ($_fetch_parent) {
                my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
                unless ($gs) {
                        die "Unable to determine upstream SVN information from ",
                            "working tree history\n";
                }
                # just fetch, don't checkout.
                $_no_checkout = 'true';
                $_fetch_all ? $gs->fetch_all : $gs->fetch;
        } elsif ($_fetch_all) {
                cmd_multi_fetch();
        } else {
                $remote ||= $Git::SVN::default_repo_id;
                Git::SVN::fetch_all($remote, Git::SVN::read_all_remotes());
        }
}

sub cmd_set_tree {
        my (@commits) = @_;
        if ($_stdin || !@commits) {
                print "Reading from stdin...\n";
                @commits = ();
                while (<STDIN>) {
                        if (/\b($sha1_short)\b/o) {
                                unshift @commits, $1;
                        }
                }
        }
        my @revs;
        foreach my $c (@commits) {
                my @tmp = command('rev-parse',$c);
                if (scalar @tmp == 1) {
                        push @revs, $tmp[0];
                } elsif (scalar @tmp > 1) {
                        push @revs, reverse(command('rev-list',@tmp));
                } else {
                        fatal "Failed to rev-parse $c";
                }
        }
        my $gs = Git::SVN->new;
        my ($r_last, $cmt_last) = $gs->last_rev_commit;
        $gs->fetch;
        if (defined $gs->{last_rev} && $r_last != $gs->{last_rev}) {
                fatal "There are new revisions that were fetched ",
                      "and need to be merged (or acknowledged) ",
                      "before committing.\nlast rev: $r_last\n",
                      " current: $gs->{last_rev}";
        }
        $gs->set_tree($_) foreach @revs;
        print "Done committing ",scalar @revs," revisions to SVN\n";
        unlink $gs->{index};
}

sub split_merge_info_range {
        my ($range) = @_;
        if ($range =~ /(\d+)-(\d+)/) {
                return (int($1), int($2));
        } else {
                return (int($range), int($range));
        }
}

sub combine_ranges {
        my ($in) = @_;

        my @fnums = ();
        my @arr = split(/,/, $in);
        for my $element (@arr) {
                my ($start, $end) = split_merge_info_range($element);
                push @fnums, $start;
        }

        my @sorted = @arr [ sort {
                $fnums[$a] <=> $fnums[$b]
        } 0..$#arr ];

        my @return = ();
        my $last = -1;
        my $first = -1;
        for my $element (@sorted) {
                my ($start, $end) = split_merge_info_range($element);

                if ($last == -1) {
                        $first = $start;
                        $last = $end;
                        next;
                }
                if ($start <= $last+1) {
                        if ($end > $last) {
                                $last = $end;
                        }
                        next;
                }
                if ($first == $last) {
                        push @return, "$first";
                } else {
                        push @return, "$first-$last";
                }
                $first = $start;
                $last = $end;
        }

        if ($first != -1) {
                if ($first == $last) {
                        push @return, "$first";
                } else {
                        push @return, "$first-$last";
                }
        }

        return join(',', @return);
}

sub merge_revs_into_hash {
        my ($hash, $minfo) = @_;
        my @lines = split(' ', $minfo);

        for my $line (@lines) {
                my ($branchpath, $revs) = split(/:/, $line);

                if (exists($hash->{$branchpath})) {
                        # Merge the two revision sets
                        my $combined = "$hash->{$branchpath},$revs";
                        $hash->{$branchpath} = combine_ranges($combined);
                } else {
                        # Just do range combining for consolidation
                        $hash->{$branchpath} = combine_ranges($revs);
                }
        }
}

sub merge_merge_info {
        my ($mergeinfo_one, $mergeinfo_two) = @_;
        my %result_hash = ();

        merge_revs_into_hash(\%result_hash, $mergeinfo_one);
        merge_revs_into_hash(\%result_hash, $mergeinfo_two);

        my $result = '';
        # Sort below is for consistency's sake
        for my $branchname (sort keys(%result_hash)) {
                my $revlist = $result_hash{$branchname};
                $result .= "$branchname:$revlist\n"
        }
        return $result;
}

sub populate_merge_info {
        my ($d, $gs, $uuid, $linear_refs, $rewritten_parent) = @_;

        my %parentshash;
        read_commit_parents(\%parentshash, $d);
        my @parents = @{$parentshash{$d}};
        if ($#parents > 0) {
                # Merge commit
                my $all_parents_ok = 1;
                my $aggregate_mergeinfo = '';
                my $rooturl = $gs->repos_root;

                if (defined($rewritten_parent)) {
                        # Replace first parent with newly-rewritten version
                        shift @parents;
                        unshift @parents, $rewritten_parent;
                }

                foreach my $parent (@parents) {
                        my ($branchurl, $svnrev, $paruuid) =
                                cmt_metadata($parent);

                        unless (defined($svnrev)) {
                                # Should have been caught be preflight check
                                fatal "merge commit $d has ancestor $parent, but that change "
                     ."does not have git-svn metadata!";
                        }
                        unless ($branchurl =~ /^\Q$rooturl\E(.*)/) {
                                fatal "commit $parent git-svn metadata changed mid-run!";
                        }
                        my $branchpath = $1;

                        my $ra = Git::SVN::Ra->new($branchurl);
                        my (undef, undef, $props) =
                                $ra->get_dir(canonicalize_path("."), $svnrev);
                        my $par_mergeinfo = $props->{'svn:mergeinfo'};
                        unless (defined $par_mergeinfo) {
                                $par_mergeinfo = '';
                        }
                        # Merge previous mergeinfo values
                        $aggregate_mergeinfo =
                                merge_merge_info($aggregate_mergeinfo,
                                                                 $par_mergeinfo, 0);

                        next if $parent eq $parents[0]; # Skip first parent
                        # Add new changes being placed in tree by merge
                        my @cmd = (qw/rev-list --reverse/,
                                           $parent, qw/--not/);
                        foreach my $par (@parents) {
                                unless ($par eq $parent) {
                                        push @cmd, $par;
                                }
                        }
                        my @revsin = ();
                        my ($revlist, $ctx) = command_output_pipe(@cmd);
                        while (<$revlist>) {
                                my $irev = $_;
                                chomp $irev;
                                my (undef, $csvnrev, undef) =
                                        cmt_metadata($irev);
                                unless (defined $csvnrev) {
                                        # A child is missing SVN annotations...
                                        # this might be OK, or might not be.
                                        warn "W:child $irev is merged into revision "
                                                 ."$d but does not have git-svn metadata. "
                                                 ."This means git-svn cannot determine the "
                                                 ."svn revision numbers to place into the "
                                                 ."svn:mergeinfo property. You must ensure "
                                                 ."a branch is entirely committed to "
                                                 ."SVN before merging it in order for "
                                                 ."svn:mergeinfo population to function "
                                                 ."properly";
                                }
                                push @revsin, $csvnrev;
                        }
                        command_close_pipe($revlist, $ctx);

                        last unless $all_parents_ok;

                        # We now have a list of all SVN revnos which are
                        # merged by this particular parent. Integrate them.
                        next if $#revsin == -1;
                        my $newmergeinfo = "$branchpath:" . join(',', @revsin);
                        $aggregate_mergeinfo =
                                merge_merge_info($aggregate_mergeinfo,
                                                                 $newmergeinfo, 1);
                }
                if ($all_parents_ok and $aggregate_mergeinfo) {
                        return $aggregate_mergeinfo;
                }
        }

        return undef;
}

sub dcommit_rebase {
        my ($is_last, $current, $fetched_ref, $svn_error) = @_;
        my @diff;

        if ($svn_error) {
                print STDERR "\nERROR from SVN:\n",
                                $svn_error->expanded_message, "\n";
        }
        unless ($_no_rebase) {
                # we always want to rebase against the current HEAD,
                # not any head that was passed to us
                @diff = command('diff-tree', $current,
                           $fetched_ref, '--');
                my @finish;
                if (@diff) {
                        @finish = rebase_cmd();
                        print STDERR "W: $current and ", $fetched_ref,
                                     " differ, using @finish:\n",
                                     join("\n", @diff), "\n";
                } elsif ($is_last) {
                        print "No changes between ", $current, " and ",
                              $fetched_ref,
                              "\nResetting to the latest ",
                              $fetched_ref, "\n";
                        @finish = qw/reset --mixed/;
                }
                command_noisy(@finish, $fetched_ref) if @finish;
        }
        if ($svn_error) {
                die "ERROR: Not all changes have been committed into SVN"
                        .($_no_rebase ? ".\n" : ", however the committed\n"
                        ."ones (if any) seem to be successfully integrated "
                        ."into the working tree.\n")
                        ."Please see the above messages for details.\n";
        }
        return @diff;
}

sub cmd_dcommit {
        my $head = shift;
        command_noisy(qw/update-index --refresh/);
        git_cmd_try { command_oneline(qw/diff-index --quiet HEAD/) }
                'Cannot dcommit with a dirty index.  Commit your changes first, '
                . "or stash them with `git stash'.\n";
        $head ||= 'HEAD';

        my $old_head;
        if ($head ne 'HEAD') {
                $old_head = eval {
                        command_oneline([qw/symbolic-ref -q HEAD/])
                };
                if ($old_head) {
                        $old_head =~ s{^refs/heads/}{};
                } else {
                        $old_head = eval { command_oneline(qw/rev-parse HEAD/) };
                }
                command(['checkout', $head], STDERR => 0);
        }

        my @refs;
        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD', \@refs);
        unless ($gs) {
                die "Unable to determine upstream SVN information from ",
                    "$head history.\nPerhaps the repository is empty.";
        }

        if (defined $_commit_url) {
                $url = $_commit_url;
        } else {
                $url = eval { command_oneline('config', '--get',
                              "svn-remote.$gs->{repo_id}.commiturl") };
                if (!$url) {
                        $url = $gs->full_pushurl
                }
        }

        my $last_rev = $_revision if defined $_revision;
        if ($url) {
                print "Committing to $url ...\n";
        }
        my ($linear_refs, $parents) = linearize_history($gs, \@refs);
        if ($_no_rebase && scalar(@$linear_refs) > 1) {
                warn "Attempting to commit more than one change while ",
                     "--no-rebase is enabled.\n",
                     "If these changes depend on each other, re-running ",
                     "without --no-rebase may be required."
        }

        if (defined $_interactive){
                my $ask_default = "y";
                foreach my $d (@$linear_refs){
                        my ($fh, $ctx) = command_output_pipe(qw(show --summary), "$d");
                        while (<$fh>){
                                print $_;
                        }
                        command_close_pipe($fh, $ctx);
                        $_ = ask("Commit this patch to SVN? ([y]es (default)|[n]o|[q]uit|[a]ll): ",
                                 valid_re => qr/^(?:yes|y|no|n|quit|q|all|a)/i,
                                 default => $ask_default);
                        die "Commit this patch reply required" unless defined $_;
                        if (/^[nq]/i) {
                                exit(0);
                        } elsif (/^a/i) {
                                last;
                        }
                }
        }

        my $expect_url = $url;

        my $push_merge_info = eval {
                command_oneline(qw/config --get svn.pushmergeinfo/)
                };
        if (not defined($push_merge_info)
                        or $push_merge_info eq "false"
                        or $push_merge_info eq "no"
                        or $push_merge_info eq "never") {
                $push_merge_info = 0;
        }

        unless (defined($_merge_info) || ! $push_merge_info) {
                # Preflight check of changes to ensure no issues with mergeinfo
                # This includes check for uncommitted-to-SVN parents
                # (other than the first parent, which we will handle),
                # information from different SVN repos, and paths
                # which are not underneath this repository root.
                my $rooturl = $gs->repos_root;
                foreach my $d (@$linear_refs) {
                        my %parentshash;
                        read_commit_parents(\%parentshash, $d);
                        my @realparents = @{$parentshash{$d}};
                        if ($#realparents > 0) {
                                # Merge commit
                                shift @realparents; # Remove/ignore first parent
                                foreach my $parent (@realparents) {
                                        my ($branchurl, $svnrev, $paruuid) = cmt_metadata($parent);
                                        unless (defined $paruuid) {
                                                # A parent is missing SVN annotations...
                                                # abort the whole operation.
                                                fatal "$parent is merged into revision $d, "
                                                         ."but does not have git-svn metadata. "
                                                         ."Either dcommit the branch or use a "
                                                         ."local cherry-pick, FF merge, or rebase "
                                                         ."instead of an explicit merge commit.";
                                        }

                                        unless ($paruuid eq $uuid) {
                                                # Parent has SVN metadata from different repository
                                                fatal "merge parent $parent for change $d has "
                                                         ."git-svn uuid $paruuid, while current change "
                                                         ."has uuid $uuid!";
                                        }

                                        unless ($branchurl =~ /^\Q$rooturl\E(.*)/) {
                                                # This branch is very strange indeed.
                                                fatal "merge parent $parent for $d is on branch "
                                                         ."$branchurl, which is not under the "
                                                         ."git-svn root $rooturl!";
                                        }
                                }
                        }
                }
        }

        my $rewritten_parent;
        my $current_head = command_oneline(qw/rev-parse HEAD/);
        Git::SVN::remove_username($expect_url);
        if (defined($_merge_info)) {
                $_merge_info =~ tr{ }{\n};
        }
        while (1) {
                my $d = shift @$linear_refs or last;
                unless (defined $last_rev) {
                        (undef, $last_rev, undef) = cmt_metadata("$d~1");
                        unless (defined $last_rev) {
                                fatal "Unable to extract revision information ",
                                      "from commit $d~1";
                        }
                }
                if ($_dry_run) {
                        print "diff-tree $d~1 $d\n";
                } else {
                        my $cmt_rev;

                        unless (defined($_merge_info) || ! $push_merge_info) {
                                $_merge_info = populate_merge_info($d, $gs,
                                                             $uuid,
                                                             $linear_refs,
                                                             $rewritten_parent);
                        }

                        my %ed_opts = ( r => $last_rev,
                                        log => get_commit_entry($d)->{log},
                                        ra => Git::SVN::Ra->new($url),
                                        config => SVN::Core::config_get_config(
                                                $Git::SVN::Ra::config_dir
                                        ),
                                        tree_a => "$d~1",
                                        tree_b => $d,
                                        editor_cb => sub {
                                               print "Committed r$_[0]\n";
                                               $cmt_rev = $_[0];
                                        },
                                        mergeinfo => $_merge_info,
                                        svn_path => '');

                        my $err_handler = $SVN::Error::handler;
                        $SVN::Error::handler = sub {
                                my $err = shift;
                                dcommit_rebase(1, $current_head, $gs->refname,
                                        $err);
                        };

                        if (!Git::SVN::Editor->new(\%ed_opts)->apply_diff) {
                                print "No changes\n$d~1 == $d\n";
                        } elsif ($parents->{$d} && @{$parents->{$d}}) {
                                $gs->{inject_parents_dcommit}->{$cmt_rev} =
                                                               $parents->{$d};
                        }
                        $_fetch_all ? $gs->fetch_all : $gs->fetch;
                        $SVN::Error::handler = $err_handler;
                        $last_rev = $cmt_rev;
                        next if $_no_rebase;

                        my @diff = dcommit_rebase(@$linear_refs == 0, $d,
                                                $gs->refname, undef);

                        $rewritten_parent = command_oneline(qw/rev-parse/,
                                                        $gs->refname);

                        if (@diff) {
                                $current_head = command_oneline(qw/rev-parse
                                                                HEAD/);
                                @refs = ();
                                my ($url_, $rev_, $uuid_, $gs_) =
                                              working_head_info('HEAD', \@refs);
                                my ($linear_refs_, $parents_) =
                                              linearize_history($gs_, \@refs);
                                if (scalar(@$linear_refs) !=
                                    scalar(@$linear_refs_)) {
                                        fatal "# of revisions changed ",
                                          "\nbefore:\n",
                                          join("\n", @$linear_refs),
                                          "\n\nafter:\n",
                                          join("\n", @$linear_refs_), "\n",
                                          'If you are attempting to commit ',
                                          "merges, try running:\n\t",
                                          'git rebase --interactive',
                                          '--preserve-merges ',
                                          $gs->refname,
                                          "\nBefore dcommitting";
                                }
                                if ($url_ ne $expect_url) {
                                        if ($url_ eq $gs->metadata_url) {
                                                print
                                                  "Accepting rewritten URL:",
                                                  " $url_\n";
                                        } else {
                                                fatal
                                                  "URL mismatch after rebase:",
                                                  " $url_ != $expect_url";
                                        }
                                }
                                if ($uuid_ ne $uuid) {
                                        fatal "uuid mismatch after rebase: ",
                                              "$uuid_ != $uuid";
                                }
                                # remap parents
                                my (%p, @l, $i);
                                for ($i = 0; $i < scalar @$linear_refs; $i++) {
                                        my $new = $linear_refs_->[$i] or next;
                                        $p{$new} =
                                                $parents->{$linear_refs->[$i]};
                                        push @l, $new;
                                }
                                $parents = \%p;
                                $linear_refs = \@l;
                                undef $last_rev;
                        }
                }
        }

        if ($old_head) {
                my $new_head = command_oneline(qw/rev-parse HEAD/);
                my $new_is_symbolic = eval {
                        command_oneline(qw/symbolic-ref -q HEAD/);
                };
                if ($new_is_symbolic) {
                        print "dcommitted the branch ", $head, "\n";
                } else {
                        print "dcommitted on a detached HEAD because you gave ",
                              "a revision argument.\n",
                              "The rewritten commit is: ", $new_head, "\n";
                }
                command(['checkout', $old_head], STDERR => 0);
        }

        unlink $gs->{index};
}

sub cmd_branch {
        my ($branch_name, $head) = @_;

        unless (defined $branch_name && length $branch_name) {
                die(($_tag ? "tag" : "branch") . " name required\n");
        }
        $head ||= 'HEAD';

        my (undef, $rev, undef, $gs) = working_head_info($head);
        my $src = $gs->full_pushurl;

        my $remote = Git::SVN::read_all_remotes()->{$gs->{repo_id}};
        my $allglobs = $remote->{ $_tag ? 'tags' : 'branches' };
        my $glob;
        if ($#{$allglobs} == 0) {
                $glob = $allglobs->[0];
        } else {
                unless(defined $_branch_dest) {
                        die "Multiple ",
                            $_tag ? "tag" : "branch",
                            " paths defined for Subversion repository.\n",
                            "You must specify where you want to create the ",
                            $_tag ? "tag" : "branch",
                            " with the --destination argument.\n";
                }
                foreach my $g (@{$allglobs}) {
                        my $re = Git::SVN::Editor::glob2pat($g->{path}->{left});
                        if ($_branch_dest =~ /$re/) {
                                $glob = $g;
                                last;
                        }
                }
                unless (defined $glob) {
                        my $dest_re = qr/\b\Q$_branch_dest\E\b/;
                        foreach my $g (@{$allglobs}) {
                                $g->{path}->{left} =~ /$dest_re/ or next;
                                if (defined $glob) {
                                        die "Ambiguous destination: ",
                                            $_branch_dest, "\nmatches both '",
                                            $glob->{path}->{left}, "' and '",
                                            $g->{path}->{left}, "'\n";
                                }
                                $glob = $g;
                        }
                        unless (defined $glob) {
                                die "Unknown ",
                                    $_tag ? "tag" : "branch",
                                    " destination $_branch_dest\n";
                        }
                }
        }
        my ($lft, $rgt) = @{ $glob->{path} }{qw/left right/};
        my $url;
        if (defined $_commit_url) {
                $url = $_commit_url;
        } else {
                $url = eval { command_oneline('config', '--get',
                        "svn-remote.$gs->{repo_id}.commiturl") };
                if (!$url) {
                        $url = $remote->{pushurl} || $remote->{url};
                }
        }
        my $dst = join '/', $url, $lft, $branch_name, ($rgt || ());

        if ($dst =~ /^https:/ && $src =~ /^http:/) {
                $src=~s/^http:/https:/;
        }

        ::_req_svn();

        my $ctx = SVN::Client->new(
                auth    => Git::SVN::Ra::_auth_providers(),
                log_msg => sub {
                        ${ $_[0] } = defined $_message
                                ? $_message
                                : 'Create ' . ($_tag ? 'tag ' : 'branch ' )
                                . $branch_name;
                },
        );

        eval {
                $ctx->ls($dst, 'HEAD', 0);
        } and die "branch ${branch_name} already exists\n";

        print "Copying ${src} at r${rev} to ${dst}...\n";
        $ctx->copy($src, $rev, $dst)
                unless $_dry_run;

        $gs->fetch_all;
}

sub cmd_find_rev {
        my $revision_or_hash = shift or die "SVN or git revision required ",
                                            "as a command-line argument\n";
        my $result;
        if ($revision_or_hash =~ /^r\d+$/) {
                my $head = shift;
                $head ||= 'HEAD';
                my @refs;
                my (undef, undef, $uuid, $gs) = working_head_info($head, \@refs);
                unless ($gs) {
                        die "Unable to determine upstream SVN information from ",
                            "$head history\n";
                }
                my $desired_revision = substr($revision_or_hash, 1);
                $result = $gs->rev_map_get($desired_revision, $uuid);
        } else {
                my (undef, $rev, undef) = cmt_metadata($revision_or_hash);
                $result = $rev;
        }
        print "$result\n" if $result;
}

sub auto_create_empty_directories {
        my ($gs) = @_;
        my $var = eval { command_oneline('config', '--get', '--bool',
                                         "svn-remote.$gs->{repo_id}.automkdirs") };
        # By default, create empty directories by consulting the unhandled log,
        # but allow setting it to 'false' to skip it.
        return !($var && $var eq 'false');
}

sub cmd_rebase {
        command_noisy(qw/update-index --refresh/);
        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
        unless ($gs) {
                die "Unable to determine upstream SVN information from ",
                    "working tree history\n";
        }
        if ($_dry_run) {
                print "Remote Branch: " . $gs->refname . "\n";
                print "SVN URL: " . $url . "\n";
                return;
        }
        if (command(qw/diff-index HEAD --/)) {
                print STDERR "Cannot rebase with uncommited changes:\n";
                command_noisy('status');
                exit 1;
        }
        unless ($_local) {
                # rebase will checkout for us, so no need to do it explicitly
                $_no_checkout = 'true';
                $_fetch_all ? $gs->fetch_all : $gs->fetch;
        }
        command_noisy(rebase_cmd(), $gs->refname);
        if (auto_create_empty_directories($gs)) {
                $gs->mkemptydirs;
        }
}

sub cmd_show_ignore {
        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
        $gs ||= Git::SVN->new;
        my $r = (defined $_revision ? $_revision : $gs->ra->get_latest_revnum);
        $gs->prop_walk($gs->{path}, $r, sub {
                my ($gs, $path, $props) = @_;
                print STDOUT "\n# $path\n";
                my $s = $props->{'svn:ignore'} or return;
                $s =~ s/[\r\n]+/\n/g;
                $s =~ s/^\n+//;
                chomp $s;
                $s =~ s#^#$path#gm;
                print STDOUT "$s\n";
        });
}

sub cmd_show_externals {
        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
        $gs ||= Git::SVN->new;
        my $r = (defined $_revision ? $_revision : $gs->ra->get_latest_revnum);
        $gs->prop_walk($gs->{path}, $r, sub {
                my ($gs, $path, $props) = @_;
                print STDOUT "\n# $path\n";
                my $s = $props->{'svn:externals'} or return;
                $s =~ s/[\r\n]+/\n/g;
                chomp $s;
                $s =~ s#^#$path#gm;
                print STDOUT "$s\n";
        });
}

sub cmd_create_ignore {
        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
        $gs ||= Git::SVN->new;
        my $r = (defined $_revision ? $_revision : $gs->ra->get_latest_revnum);
        $gs->prop_walk($gs->{path}, $r, sub {
                my ($gs, $path, $props) = @_;
                # $path is of the form /path/to/dir/
                $path = '.' . $path;
                # SVN can have attributes on empty directories,
                # which git won't track
                mkpath([$path]) unless -d $path;
                my $ignore = $path . '.gitignore';
                my $s = $props->{'svn:ignore'} or return;
                open(GITIGNORE, '>', $ignore)
                  or fatal("Failed to open `$ignore' for writing: $!");
                $s =~ s/[\r\n]+/\n/g;
                $s =~ s/^\n+//;
                chomp $s;
                # Prefix all patterns so that the ignore doesn't apply
                # to sub-directories.
                $s =~ s#^#/#gm;
                print GITIGNORE "$s\n";
                close(GITIGNORE)
                  or fatal("Failed to close `$ignore': $!");
                command_noisy('add', '-f', $ignore);
        });
}

sub cmd_mkdirs {
        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
        $gs ||= Git::SVN->new;
        $gs->mkemptydirs($_revision);
}

sub canonicalize_path {
        my ($path) = @_;
        my $dot_slash_added = 0;
        if (substr($path, 0, 1) ne "/") {
                $path = "./" . $path;
                $dot_slash_added = 1;
        }
        # File::Spec->canonpath doesn't collapse x/../y into y (for a
        # good reason), so let's do this manually.
        $path =~ s#/+#/#g;
        $path =~ s#/\.(?:/|$)#/#g;
        $path =~ s#/[^/]+/\.\.##g;
        $path =~ s#/$##g;
        $path =~ s#^\./## if $dot_slash_added;
        $path =~ s#^/##;
        $path =~ s#^\.$##;
        return $path;
}

sub canonicalize_url {
        my ($url) = @_;
        $url =~ s#^([^:]+://[^/]*/)(.*)$#$1 . canonicalize_path($2)#e;
        return $url;
}

# get_svnprops(PATH)
# ------------------
# Helper for cmd_propget and cmd_proplist below.
sub get_svnprops {
        my $path = shift;
        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
        $gs ||= Git::SVN->new;

        # prefix THE PATH by the sub-directory from which the user
        # invoked us.
        $path = $cmd_dir_prefix . $path;
        fatal("No such file or directory: $path") unless -e $path;
        my $is_dir = -d $path ? 1 : 0;
        $path = $gs->{path} . '/' . $path;

        # canonicalize the path (otherwise libsvn will abort or fail to
        # find the file)
        $path = canonicalize_path($path);

        my $r = (defined $_revision ? $_revision : $gs->ra->get_latest_revnum);
        my $props;
        if ($is_dir) {
                (undef, undef, $props) = $gs->ra->get_dir($path, $r);
        }
        else {
                (undef, $props) = $gs->ra->get_file($path, $r, undef);
        }
        return $props;
}

# cmd_propget (PROP, PATH)
# ------------------------
# Print the SVN property PROP for PATH.
sub cmd_propget {
        my ($prop, $path) = @_;
        $path = '.' if not defined $path;
        usage(1) if not defined $prop;
        my $props = get_svnprops($path);
        if (not defined $props->{$prop}) {
                fatal("`$path' does not have a `$prop' SVN property.");
        }
        print $props->{$prop} . "\n";
}

# cmd_proplist (PATH)
# -------------------
# Print the list of SVN properties for PATH.
sub cmd_proplist {
        my $path = shift;
        $path = '.' if not defined $path;
        my $props = get_svnprops($path);
        print "Properties on '$path':\n";
        foreach (sort keys %{$props}) {
                print "  $_\n";
        }
}

sub cmd_multi_init {
        my $url = shift;
        unless (defined $_trunk || @_branches || @_tags) {
                usage(1);
        }

        $_prefix = '' unless defined $_prefix;
        if (defined $url) {
                $url = canonicalize_url($url);
                init_subdir(@_);
        }
        do_git_init_db();
        if (defined $_trunk) {
                $_trunk =~ s#^/+##;
                my $trunk_ref = 'refs/remotes/' . $_prefix . 'trunk';
                # try both old-style and new-style lookups:
                my $gs_trunk = eval { Git::SVN->new($trunk_ref) };
                unless ($gs_trunk) {
                        my ($trunk_url, $trunk_path) =
                                              complete_svn_url($url, $_trunk);
                        $gs_trunk = Git::SVN->init($trunk_url, $trunk_path,
                                                   undef, $trunk_ref);
                }
        }
        return unless @_branches || @_tags;
        my $ra = $url ? Git::SVN::Ra->new($url) : undef;
        foreach my $path (@_branches) {
                complete_url_ls_init($ra, $path, '--branches/-b', $_prefix);
        }
        foreach my $path (@_tags) {
                complete_url_ls_init($ra, $path, '--tags/-t', $_prefix.'tags/');
        }
}

sub cmd_multi_fetch {
        $Git::SVN::no_reuse_existing = undef;
        my $remotes = Git::SVN::read_all_remotes();
        foreach my $repo_id (sort keys %$remotes) {
                if ($remotes->{$repo_id}->{url}) {
                        Git::SVN::fetch_all($repo_id, $remotes);
                }
        }
}

# this command is special because it requires no metadata
sub cmd_commit_diff {
        my ($ta, $tb, $url) = @_;
        my $usage = "Usage: $0 commit-diff -r<revision> ".
                    "<tree-ish> <tree-ish> [<URL>]";
        fatal($usage) if (!defined $ta || !defined $tb);
        my $svn_path = '';
        if (!defined $url) {
                my $gs = eval { Git::SVN->new };
                if (!$gs) {
                        fatal("Needed URL or usable git-svn --id in ",
                              "the command-line\n", $usage);
                }
                $url = $gs->{url};
                $svn_path = $gs->{path};
        }
        unless (defined $_revision) {
                fatal("-r|--revision is a required argument\n", $usage);
        }
        if (defined $_message && defined $_file) {
                fatal("Both --message/-m and --file/-F specified ",
                      "for the commit message.\n",
                      "I have no idea what you mean");
        }
        if (defined $_file) {
                $_message = file_to_s($_file);
        } else {
                $_message ||= get_commit_entry($tb)->{log};
        }
        my $ra ||= Git::SVN::Ra->new($url);
        my $r = $_revision;
        if ($r eq 'HEAD') {
                $r = $ra->get_latest_revnum;
        } elsif ($r !~ /^\d+$/) {
                die "revision argument: $r not understood by git-svn\n";
        }
        my %ed_opts = ( r => $r,
                        log => $_message,
                        ra => $ra,
                        tree_a => $ta,
                        tree_b => $tb,
                        editor_cb => sub { print "Committed r$_[0]\n" },
                        svn_path => $svn_path );
        if (!Git::SVN::Editor->new(\%ed_opts)->apply_diff) {
                print "No changes\n$ta == $tb\n";
        }
}

sub escape_uri_only {
        my ($uri) = @_;
        my @tmp;
        foreach (split m{/}, $uri) {
                s/([^~\w.%+-]|%(?![a-fA-F0-9]{2}))/sprintf("%%%02X",ord($1))/eg;
                push @tmp, $_;
        }
        join('/', @tmp);
}

sub escape_url {
        my ($url) = @_;
        if ($url =~ m#^([^:]+)://([^/]*)(.*)$#) {
                my ($scheme, $domain, $uri) = ($1, $2, escape_uri_only($3));
                $url = "$scheme://$domain$uri";
        }
        $url;
}

sub cmd_info {
        my $path = canonicalize_path(defined($_[0]) ? $_[0] : ".");
        my $fullpath = canonicalize_path($cmd_dir_prefix . $path);
        if (exists $_[1]) {
                die "Too many arguments specified\n";
        }

        my ($file_type, $diff_status) = find_file_type_and_diff_status($path);

        if (!$file_type && !$diff_status) {
                print STDERR "svn: '$path' is not under version control\n";
                exit 1;
        }

        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
        unless ($gs) {
                die "Unable to determine upstream SVN information from ",
                    "working tree history\n";
        }

        # canonicalize_path() will return "" to make libsvn 1.5.x happy,
        $path = "." if $path eq "";

        my $full_url = $url . ($fullpath eq "" ? "" : "/$fullpath");

        if ($_url) {
                print escape_url($full_url), "\n";
                return;
        }

        my $result = "Path: $path\n";
        $result .= "Name: " . basename($path) . "\n" if $file_type ne "dir";
        $result .= "URL: " . escape_url($full_url) . "\n";

        eval {
                my $repos_root = $gs->repos_root;
                Git::SVN::remove_username($repos_root);
                $result .= "Repository Root: " . escape_url($repos_root) . "\n";
        };
        if ($@) {
                $result .= "Repository Root: (offline)\n";
        }
        ::_req_svn();
        $result .= "Repository UUID: $uuid\n" unless $diff_status eq "A" &&
                (::compare_svn_version('1.5.4') <= 0 || $file_type ne "dir");
        $result .= "Revision: " . ($diff_status eq "A" ? 0 : $rev) . "\n";

        $result .= "Node Kind: " .
                   ($file_type eq "dir" ? "directory" : "file") . "\n";

        my $schedule = $diff_status eq "A"
                       ? "add"
                       : ($diff_status eq "D" ? "delete" : "normal");
        $result .= "Schedule: $schedule\n";

        if ($diff_status eq "A") {
                print $result, "\n";
                return;
        }

        my ($lc_author, $lc_rev, $lc_date_utc);
        my @args = Git::SVN::Log::git_svn_log_cmd($rev, $rev, "--", $fullpath);
        my $log = command_output_pipe(@args);
        my $esc_color = qr/(?:\033\[(?:(?:\d+;)*\d*)?m)*/;
        while (<$log>) {
                if (/^${esc_color}author (.+) <[^>]+> (\d+) ([\-\+]?\d+)$/o) {
                        $lc_author = $1;
                        $lc_date_utc = Git::SVN::Log::parse_git_date($2, $3);
                } elsif (/^${esc_color}    (git-svn-id:.+)$/o) {
                        (undef, $lc_rev, undef) = ::extract_metadata($1);
                }
        }
        close $log;

        Git::SVN::Log::set_local_timezone();

        $result .= "Last Changed Author: $lc_author\n";
        $result .= "Last Changed Rev: $lc_rev\n";
        $result .= "Last Changed Date: " .
                   Git::SVN::Log::format_svn_date($lc_date_utc) . "\n";

        if ($file_type ne "dir") {
                my $text_last_updated_date =
                    ($diff_status eq "D" ? $lc_date_utc : (stat $path)[9]);
                $result .=
                    "Text Last Updated: " .
                    Git::SVN::Log::format_svn_date($text_last_updated_date) .
                    "\n";
                my $checksum;
                if ($diff_status eq "D") {
                        my ($fh, $ctx) =
                            command_output_pipe(qw(cat-file blob), "HEAD:$path");
                        if ($file_type eq "link") {
                                my $file_name = <$fh>;
                                $checksum = md5sum("link $file_name");
                        } else {
                                $checksum = md5sum($fh);
                        }
                        command_close_pipe($fh, $ctx);
                } elsif ($file_type eq "link") {
                        my $file_name =
                            command(qw(cat-file blob), "HEAD:$path");
                        $checksum =
                            md5sum("link " . $file_name);
                } else {
                        open FILE, "<", $path or die $!;
                        $checksum = md5sum(\*FILE);
                        close FILE or die $!;
                }
                $result .= "Checksum: " . $checksum . "\n";
        }

        print $result, "\n";
}

sub cmd_reset {
        my $target = shift || $_revision or die "SVN revision required\n";
        $target = $1 if $target =~ /^r(\d+)$/;
        $target =~ /^\d+$/ or die "Numeric SVN revision expected\n";
        my ($url, $rev, $uuid, $gs) = working_head_info('HEAD');
        unless ($gs) {
                die "Unable to determine upstream SVN information from ".
                    "history\n";
        }
        my ($r, $c) = $gs->find_rev_before($target, not $_fetch_parent);
        die "Cannot find SVN revision $target\n" unless defined($c);
        $gs->rev_map_set($r, $c, 'reset', $uuid);
        print "r$r = $c ($gs->{ref_id})\n";
}

sub cmd_gc {
        if (!can_compress()) {
                warn "Compress::Zlib could not be found; unhandled.log " .
                     "files will not be compressed.\n";
        }
        find({ wanted => \&gc_directory, no_chdir => 1}, "$ENV{GIT_DIR}/svn");
}

########################### utility functions #########################

sub rebase_cmd {
        my @cmd = qw/rebase/;
        push @cmd, '-v' if $_verbose;
        push @cmd, qw/--merge/ if $_merge;
        push @cmd, "--strategy=$_strategy" if $_strategy;
        push @cmd, "--preserve-merges" if $_preserve_merges;
        @cmd;
}

sub post_fetch_checkout {
        return if $_no_checkout;
        return if verify_ref('HEAD^0');
        my $gs = $Git::SVN::_head or return;

        # look for "trunk" ref if it exists
        my $remote = Git::SVN::read_all_remotes()->{$gs->{repo_id}};
        my $fetch = $remote->{fetch};
        if ($fetch) {
                foreach my $p (keys %$fetch) {
                        basename($fetch->{$p}) eq 'trunk' or next;
                        $gs = Git::SVN->new($fetch->{$p}, $gs->{repo_id}, $p);
                        last;
                }
        }

        command_noisy(qw(update-ref HEAD), $gs->refname);
        return unless verify_ref('HEAD^0');

        return if $ENV{GIT_DIR} !~ m#^(?:.*/)?\.git$#;
        my $index = $ENV{GIT_INDEX_FILE} || "$ENV{GIT_DIR}/index";
        return if -f $index;

        return if command_oneline(qw/rev-parse --is-inside-work-tree/) eq 'false';
        return if command_oneline(qw/rev-parse --is-inside-git-dir/) eq 'true';
        command_noisy(qw/read-tree -m -u -v HEAD HEAD/);
        print STDERR "Checked out HEAD:\n  ",
                     $gs->full_url, " r", $gs->last_rev, "\n";
        if (auto_create_empty_directories($gs)) {
                $gs->mkemptydirs($gs->last_rev);
        }
}

sub complete_svn_url {
        my ($url, $path) = @_;
        $path =~ s#/+$##;
        if ($path !~ m#^[a-z\+]+://#) {
                if (!defined $url || $url !~ m#^[a-z\+]+://#) {
                        fatal("E: '$path' is not a complete URL ",
                              "and a separate URL is not specified");
                }
                return ($url, $path);
        }
        return ($path, '');
}

sub complete_url_ls_init {
        my ($ra, $repo_path, $switch, $pfx) = @_;
        unless ($repo_path) {
                print STDERR "W: $switch not specified\n";
                return;
        }
        $repo_path =~ s#/+$##;
        if ($repo_path =~ m#^[a-z\+]+://#) {
                $ra = Git::SVN::Ra->new($repo_path);
                $repo_path = '';
        } else {
                $repo_path =~ s#^/+##;
                unless ($ra) {
                        fatal("E: '$repo_path' is not a complete URL ",
                              "and a separate URL is not specified");
                }
        }
        my $url = $ra->{url};
        my $gs = Git::SVN->init($url, undef, undef, undef, 1);
        my $k = "svn-remote.$gs->{repo_id}.url";
        my $orig_url = eval { command_oneline(qw/config --get/, $k) };
        if ($orig_url && ($orig_url ne $gs->{url})) {
                die "$k already set: $orig_url\n",
                    "wanted to set to: $gs->{url}\n";
        }
        command_oneline('config', $k, $gs->{url}) unless $orig_url;
        my $remote_path = "$gs->{path}/$repo_path";
        $remote_path =~ s{%([0-9A-F]{2})}{chr hex($1)}ieg;
        $remote_path =~ s#/+#/#g;
        $remote_path =~ s#^/##g;
        $remote_path .= "/*" if $remote_path !~ /\*/;
        my ($n) = ($switch =~ /^--(\w+)/);
        if (length $pfx && $pfx !~ m#/$#) {
                die "--prefix='$pfx' must have a trailing slash '/'\n";
        }
        command_noisy('config',
                      '--add',
                      "svn-remote.$gs->{repo_id}.$n",
                      "$remote_path:refs/remotes/$pfx*" .
                        ('/*' x (($remote_path =~ tr/*/*/) - 1)) );
}

sub verify_ref {
        my ($ref) = @_;
        eval { command_oneline([ 'rev-parse', '--verify', $ref ],
                               { STDERR => 0 }); };
}

sub get_tree_from_treeish {
        my ($treeish) = @_;
        # $treeish can be a symbolic ref, too:
        my $type = command_oneline(qw/cat-file -t/, $treeish);
        my $expected;
        while ($type eq 'tag') {
                ($treeish, $type) = command(qw/cat-file tag/, $treeish);
        }
        if ($type eq 'commit') {
                $expected = (grep /^tree /, command(qw/cat-file commit/,
                                                    $treeish))[0];
                ($expected) = ($expected =~ /^tree ($sha1)$/o);
                die "Unable to get tree from $treeish\n" unless $expected;
        } elsif ($type eq 'tree') {
                $expected = $treeish;
        } else {
                die "$treeish is a $type, expected tree, tag or commit\n";
        }
        return $expected;
}

sub get_commit_entry {
        my ($treeish) = shift;
        my %log_entry = ( log => '', tree => get_tree_from_treeish($treeish) );
        my $commit_editmsg = "$ENV{GIT_DIR}/COMMIT_EDITMSG";
        my $commit_msg = "$ENV{GIT_DIR}/COMMIT_MSG";
        open my $log_fh, '>', $commit_editmsg or croak $!;

        my $type = command_oneline(qw/cat-file -t/, $treeish);
        if ($type eq 'commit' || $type eq 'tag') {
                my ($msg_fh, $ctx) = command_output_pipe('cat-file',
                                                         $type, $treeish);
                my $in_msg = 0;
                my $author;
                my $saw_from = 0;
                my $msgbuf = "";
                while (<$msg_fh>) {
                        if (!$in_msg) {
                                $in_msg = 1 if (/^\s*$/);
                                $author = $1 if (/^author (.*>)/);
                        } elsif (/^git-svn-id: /) {
                                # skip this for now, we regenerate the
                                # correct one on re-fetch anyways
                                # TODO: set *:merge properties or like...
                        } else {
                                if (/^From:/ || /^Signed-off-by:/) {
                                        $saw_from = 1;
                                }
                                $msgbuf .= $_;
                        }
                }
                $msgbuf =~ s/\s+$//s;
                if ($Git::SVN::_add_author_from && defined($author)
                    && !$saw_from) {
                        $msgbuf .= "\n\nFrom: $author";
                }
                print $log_fh $msgbuf or croak $!;
                command_close_pipe($msg_fh, $ctx);
        }
        close $log_fh or croak $!;

        if ($_edit || ($type eq 'tree')) {
                chomp(my $editor = command_oneline(qw(var GIT_EDITOR)));
                system('sh', '-c', $editor.' "$@"', $editor, $commit_editmsg);
        }
        rename $commit_editmsg, $commit_msg or croak $!;
        {
                require Encode;
                # SVN requires messages to be UTF-8 when entering the repo
                local $/;
                open $log_fh, '<', $commit_msg or croak $!;
                binmode $log_fh;
                chomp($log_entry{log} = <$log_fh>);

                my $enc = Git::config('i18n.commitencoding') || 'UTF-8';
                my $msg = $log_entry{log};

                eval { $msg = Encode::decode($enc, $msg, 1) };
                if ($@) {
                        die "Could not decode as $enc:\n", $msg,
                            "\nPerhaps you need to set i18n.commitencoding\n";
                }

                eval { $msg = Encode::encode('UTF-8', $msg, 1) };
                die "Could not encode as UTF-8:\n$msg\n" if $@;

                $log_entry{log} = $msg;

                close $log_fh or croak $!;
        }
        unlink $commit_msg;
        \%log_entry;
}

sub s_to_file {
        my ($str, $file, $mode) = @_;
        open my $fd,'>',$file or croak $!;
        print $fd $str,"\n" or croak $!;
        close $fd or croak $!;
        chmod ($mode &~ umask, $file) if (defined $mode);
}

sub file_to_s {
        my $file = shift;
        open my $fd,'<',$file or croak "$!: file: $file\n";
        local $/;
        my $ret = <$fd>;
        close $fd or croak $!;
        $ret =~ s/\s*$//s;
        return $ret;
}

# '<svn username> = real-name <email address>' mapping based on git-svnimport:
sub load_authors {
        open my $authors, '<', $_authors or die "Can't open $_authors $!\n";
        my $log = $cmd eq 'log';
        while (<$authors>) {
                chomp;
                next unless /^(.+?|\(no author\))\s*=\s*(.+?)\s*<(.+)>\s*$/;
                my ($user, $name, $email) = ($1, $2, $3);
                if ($log) {
                        $Git::SVN::Log::rusers{"$name <$email>"} = $user;
                } else {
                        $users{$user} = [$name, $email];
                }
        }
        close $authors or croak $!;
}

# convert GetOpt::Long specs for use by git-config
sub read_git_config {
        my $opts = shift;
        my @config_only;
        foreach my $o (keys %$opts) {
                # if we have mixedCase and a long option-only, then
                # it's a config-only variable that we don't need for
                # the command-line.
                push @config_only, $o if ($o =~ /[A-Z]/ && $o =~ /^[a-z]+$/i);
                my $v = $opts->{$o};
                my ($key) = ($o =~ /^([a-zA-Z\-]+)/);
                $key =~ s/-//g;
                my $arg = 'git config';
                $arg .= ' --int' if ($o =~ /[:=]i$/);
                $arg .= ' --bool' if ($o !~ /[:=][sfi]$/);
                if (ref $v eq 'ARRAY') {
                        chomp(my @tmp = `$arg --get-all svn.$key`);
                        @$v = @tmp if @tmp;
                } else {
                        chomp(my $tmp = `$arg --get svn.$key`);
                        if ($tmp && !($arg =~ / --bool/ && $tmp eq 'false')) {
                                $$v = $tmp;
                        }
                }
        }
        delete @$opts{@config_only} if @config_only;
}

sub extract_metadata {
        my $id = shift or return (undef, undef, undef);
        my ($url, $rev, $uuid) = ($id =~ /^\s*git-svn-id:\s+(.*)\@(\d+)
                                                        \s([a-f\d\-]+)$/ix);
        if (!defined $rev || !$uuid || !$url) {
                # some of the original repositories I made had
                # identifiers like this:
                ($rev, $uuid) = ($id =~/^\s*git-svn-id:\s(\d+)\@([a-f\d\-]+)/i);
        }
        return ($url, $rev, $uuid);
}

sub cmt_metadata {
        return extract_metadata((grep(/^git-svn-id: /,
                command(qw/cat-file commit/, shift)))[-1]);
}

sub cmt_sha2rev_batch {
        my %s2r;
        my ($pid, $in, $out, $ctx) = command_bidi_pipe(qw/cat-file --batch/);
        my $list = shift;

        foreach my $sha (@{$list}) {
                my $first = 1;
                my $size = 0;
                print $out $sha, "\n";

                while (my $line = <$in>) {
                        if ($first && $line =~ /^[[:xdigit:]]{40}\smissing$/) {
                                last;
                        } elsif ($first &&
                               $line =~ /^[[:xdigit:]]{40}\scommit\s(\d+)$/) {
                                $first = 0;
                                $size = $1;
                                next;
                        } elsif ($line =~ /^(git-svn-id: )/) {
                                my (undef, $rev, undef) =
                                                      extract_metadata($line);
                                $s2r{$sha} = $rev;
                        }

                        $size -= length($line);
                        last if ($size == 0);
                }
        }

        command_close_bidi_pipe($pid, $in, $out, $ctx);

        return \%s2r;
}

sub working_head_info {
        my ($head, $refs) = @_;
        my @args = qw/rev-list --first-parent --pretty=medium/;
        my ($fh, $ctx) = command_output_pipe(@args, $head);
        my $hash;
        my %max;
        while (<$fh>) {
                if ( m{^commit ($::sha1)$} ) {
                        unshift @$refs, $hash if $hash and $refs;
                        $hash = $1;
                        next;
                }
                next unless s{^\s*(git-svn-id:)}{$1};
                my ($url, $rev, $uuid) = extract_metadata($_);
                if (defined $url && defined $rev) {
                        next if $max{$url} and $max{$url} < $rev;
                        if (my $gs = Git::SVN->find_by_url($url)) {
                                my $c = $gs->rev_map_get($rev, $uuid);
                                if ($c && $c eq $hash) {
                                        close $fh; # break the pipe
                                        return ($url, $rev, $uuid, $gs);
                                } else {
                                        $max{$url} ||= $gs->rev_map_max;
                                }
                        }
                }
        }
        command_close_pipe($fh, $ctx);
        (undef, undef, undef, undef);
}

sub read_commit_parents {
        my ($parents, $c) = @_;
        chomp(my $p = command_oneline(qw/rev-list --parents -1/, $c));
        $p =~ s/^($c)\s*// or die "rev-list --parents -1 $c failed!\n";
        @{$parents->{$c}} = split(/ /, $p);
}

sub linearize_history {
        my ($gs, $refs) = @_;
        my %parents;
        foreach my $c (@$refs) {
                read_commit_parents(\%parents, $c);
        }

        my @linear_refs;
        my %skip = ();
        my $last_svn_commit = $gs->last_commit;
        foreach my $c (reverse @$refs) {
                next if $c eq $last_svn_commit;
                last if $skip{$c};

                unshift @linear_refs, $c;
                $skip{$c} = 1;

                # we only want the first parent to diff against for linear
                # history, we save the rest to inject when we finalize the
                # svn commit
                my $fp_a = verify_ref("$c~1");
                my $fp_b = shift @{$parents{$c}} if $parents{$c};
                if (!$fp_a || !$fp_b) {
                        die "Commit $c\n",
                            "has no parent commit, and therefore ",
                            "nothing to diff against.\n",
                            "You should be working from a repository ",
                            "originally created by git-svn\n";
                }
                if ($fp_a ne $fp_b) {
                        die "$c~1 = $fp_a, however parsing commit $c ",
                            "revealed that:\n$c~1 = $fp_b\nBUG!\n";
                }

                foreach my $p (@{$parents{$c}}) {
                        $skip{$p} = 1;
                }
        }
        (\@linear_refs, \%parents);
}

sub find_file_type_and_diff_status {
        my ($path) = @_;
        return ('dir', '') if $path eq '';

        my $diff_output =
            command_oneline(qw(diff --cached --name-status --), $path) || "";
        my $diff_status = (split(' ', $diff_output))[0] || "";

        my $ls_tree = command_oneline(qw(ls-tree HEAD), $path) || "";

        return (undef, undef) if !$diff_status && !$ls_tree;

        if ($diff_status eq "A") {
                return ("link", $diff_status) if -l $path;
                return ("dir", $diff_status) if -d $path;
                return ("file", $diff_status);
        }

        my $mode = (split(' ', $ls_tree))[0] || "";

        return ("link", $diff_status) if $mode eq "120000";
        return ("dir", $diff_status) if $mode eq "040000";
        return ("file", $diff_status);
}

sub md5sum {
        my $arg = shift;
        my $ref = ref $arg;
        my $md5 = Digest::MD5->new();
        if ($ref eq 'GLOB' || $ref eq 'IO::File' || $ref eq 'File::Temp') {
                $md5->addfile($arg) or croak $!;
        } elsif ($ref eq 'SCALAR') {
                $md5->add($$arg) or croak $!;
        } elsif (!$ref) {
                $md5->add($arg) or croak $!;
        } else {
                fatal "Can't provide MD5 hash for unknown ref type: '", $ref, "'";
        }
        return $md5->hexdigest();
}

sub gc_directory {
        if (can_compress() && -f $_ && basename($_) eq "unhandled.log") {
                my $out_filename = $_ . ".gz";
                open my $in_fh, "<", $_ or die "Unable to open $_: $!\n";
                binmode $in_fh;
                my $gz = Compress::Zlib::gzopen($out_filename, "ab") or
                                die "Unable to open $out_filename: $!\n";

                my $res;
                while ($res = sysread($in_fh, my $str, 1024)) {
                        $gz->gzwrite($str) or
                                die "Unable to write: ".$gz->gzerror()."!\n";
                }
                unlink $_ or die "unlink $File::Find::name: $!\n";
        } elsif (-f $_ && basename($_) eq "index") {
                unlink $_ or die "unlink $_: $!\n";
        }
}

__END__

Data structures:


$remotes = { # returned by read_all_remotes()
        'svn' => {
                # svn-remote.svn.url=https://svn.musicpd.org
                url => 'https://svn.musicpd.org',
                # svn-remote.svn.fetch=mpd/trunk:trunk
                fetch => {
                        'mpd/trunk' => 'trunk',
                },
                # svn-remote.svn.tags=mpd/tags/*:tags/*
                tags => {
                        path => {
                                left => 'mpd/tags',
                                right => '',
                                regex => qr!mpd/tags/([^/]+)$!,
                                glob => 'tags/*',
                        },
                        ref => {
                                left => 'tags',
                                right => '',
                                regex => qr!tags/([^/]+)$!,
                                glob => 'tags/*',
                        },
                }
        }
};

$log_entry hashref as returned by libsvn_log_entry()
{
        log => 'whitespace-formatted log entry
',                                              # trailing newline is preserved
        revision => '8',                        # integer
        date => '2004-02-24T17:01:44.108345Z',  # commit date
        author => 'committer name'
};


# this is generated by generate_diff();
@mods = array of diff-index line hashes, each element represents one line
        of diff-index output

diff-index line ($m hash)
{
        mode_a => first column of diff-index output, no leading ':',
        mode_b => second column of diff-index output,
        sha1_b => sha1sum of the final blob,
        chg => change type [MCRADT],
        file_a => original file name of a file (iff chg is 'C' or 'R')
        file_b => new/current file name of a file (any chg)
}
;

# retval of read_url_paths{,_all}();
$l_map = {
        # repository root url
        'https://svn.musicpd.org' => {
                # repository path               # GIT_SVN_ID
                'mpd/trunk'             =>      'trunk',
                'mpd/tags/0.11.5'       =>      'tags/0.11.5',
        },
}

Notes:
        I don't trust the each() function on unless I created %hash myself
        because the internal iterator may not have started at base.