sync-all

#!/usr/bin/env perl

use warnings;
use strict;
use Cwd;
use English;

$| = 1; # autoflush stdout after each print, to avoid output after die

my $initial_working_directory;
my $exit_via_die;

my $defaultrepo;
my @packages;
my $verbose = 2;
my $try_to_resume = 0;
my $ignore_failure = 0;
my $checked_out_flag = 0; # NOT the opposite of bare_flag (describes remote repo state)
my $get_mode;
my $bare_flag = ""; # NOT the opposite of checked_out_flag (describes local repo state)

my %tags;

my $GITHUB = qr!(?:git@|git://|https://|http://|ssh://git@)github.com!;

sub inDir {
    my $dir = shift;
    my $code = shift;

    if ($dir ne '.') {
        chdir($dir);
    }

    my $result = &$code();

    if ($dir ne '.') {
        chdir($initial_working_directory);
    }
    return $result;
}

sub parsePackages {
    my @repos;
    my $lineNum;

    open IN, "< packages.conf"
        or open IN, "< packages" # clashes with packages directory when using --bare
        or die "Can't open packages file (or packages.conf)";
    @repos = <IN>;
    close IN;

    @packages = ();
    $lineNum = 0;
    foreach (@repos) {
        chomp;
        $lineNum++;
        if (/^([^# ]+) +([^ ]+) +([^ ]+) +([^ ]+)$/) {
            my %line;
            $line{"localpath"}  = $1;
            $line{"tag"}        = $2;
            $line{"remotepath"} = $3;
            $line{"upstreamurl"}= $4;
            push @packages, \%line;

            $tags{$2} = 0;
        }
        elsif (! /^(#.*)?$/) {
            die "Bad content on line $lineNum of packages file: $_";
        }
    }
}

sub tryReadFile {
    my $filename = shift;
    my @lines;

    open (FH, $filename) or return "";
    @lines = <FH>;
    close FH;
    return join('', @lines);
}

sub message {
    if ($verbose >= 2) {
        print "@_\n";
    }
}

sub warning {
    if ($verbose >= 1) {
        print "warning: @_\n";
    }
}

sub gitNewWorkdir {
    my $dir = shift;
    my $target = shift;
    my $target_dir = "$target/$dir";

    if ($dir eq '.') {
        message "== running git-new-workdir . $target_dir @_";
    } else {
        message "== $dir: running git-new-workdir . $target_dir @_";
        chdir($dir);
    }

    system ("git-new-workdir", ".", $target_dir, @_) == 0
        or $ignore_failure
        or die "git-new-workdir failed: $?";

    if ($dir ne '.') {
        chdir($initial_working_directory);
    }
}

sub git {
    my $dir = shift;
    my @args = @_;

    &inDir($dir, sub {
        my $prefix = $dir eq '.' ? "" : "$dir: ";
        message "== ${prefix}running git @args";

        system ("git", @args) == 0
            or $ignore_failure
            or die "git failed: $?";
    });
}

sub readgitline {
    my $dir = shift;
    my @args = @_;

    &inDir($dir, sub {
        open my $fh, '-|', 'git', @args
            or die "Executing git @args failed: $!";
        my $line = <$fh>;
        $line = "" unless defined($line);
        chomp $line;
        close $fh;
        return $line;
    });
}

sub readgit {
    my $dir = shift;
    my @args = @_;

    &inDir($dir, sub {
        open my $fh, '-|', 'git', @args
            or die "Executing git @args failed: $!";
        my $ret;
        $ret .= $_ while <$fh>;
        close $fh;
        return $ret;
    });
}

sub configure_repository {
    my $localpath = shift;

    &git($localpath, "config", "--local", "core.ignorecase", "true");

    my $autocrlf = &readgitline($localpath, 'config', '--get', 'core.autocrlf');
    if ($autocrlf eq "true") {
        &git($localpath, "config", "--local", "core.autocrlf", "false");
        &git($localpath, "reset", "--hard");
    }
}

# Figure out where to get the other repositories from.
sub getrepo {
    my $repo;

    if (defined($defaultrepo)) {
        $repo = $defaultrepo;
        chomp $repo;
    } else {
        # Figure out where to get the other repositories from,
        # based on where this GHC repo came from.
        my $git_dir = $bare_flag ? "ghc.git" : ".";
        my $branch = &readgitline($git_dir, "rev-parse", "--abbrev-ref", "HEAD");
        die "Bad branch: $branch"
            unless $branch =~ m!^[a-zA-Z][a-zA-Z0-9./-]*$!;
        my $remote = &readgitline($git_dir, "config", "branch.$branch.remote");
        if ($remote eq "") {
            # remotes are not mandatory for branches (e.g. not recorded by default for bare repos)
            $remote = "origin";
        }
        die "Bad remote: $remote"
            unless $remote =~ m!^[a-zA-Z][a-zA-Z0-9./-]*$!;
        $repo = &readgitline($git_dir, "config", "remote.$remote.url");
    }

    my $repo_base;
    my $checked_out_tree;
    my $repo_local = 0;

    if ($repo =~ /^...*:/) {
        # HTTP or SSH
        # Above regex says "at least two chars before the :", to avoid
        # catching Win32 drives ("C:\").
        $repo_base = $repo;

        # --checked-out is needed if you want to use a checked-out repo
        # over SSH or HTTP
        if ($checked_out_flag) {
            $checked_out_tree = 1;
        } else {
            $checked_out_tree = 0;
        }

        # Don't drop the last part of the path if specified with -r, as
        # it expects repos of the form:
        #
        #   http://git.haskell.org
        #
        # rather than
        #
        #   http://git.haskell.org/ghc
        #
        if (!$defaultrepo) {
            $repo_base =~ s#/[^/]+/?$##;
        }
    }
    elsif ($repo =~ /^\/|\.\.\/|.:(\/|\\)/) {
        # Local filesystem, either absolute (C:/ or /) or relative (../) path
        $repo_local = 1;
        $repo_base = $repo;
        if (-f "$repo/HEAD") {
            # assume a local mirror:
            $checked_out_tree = 0;
            $repo_base =~ s#/[^/]+/?$##;
        } elsif (-d "$repo/ghc.git") {
            # assume a local mirror:
            $checked_out_tree = 0;
        } else {
            # assume a checked-out tree:
            $checked_out_tree = 1;
        }
    }
    else {
        die "Couldn't work out repo";
    }

    return $repo_base, $checked_out_tree, $repo_local;
}

sub gitall {
    my $command = shift;

    my $localpath;
    my $tag;
    my $remotepath;
    my $line;
    my $branch_name;
    my $subcommand;

    my $path;

    my @args;

    my $started;
    my $doing;
    my $start_repo;

    my ($repo_base, $checked_out_tree, $repo_local) = getrepo();

    my $is_github_repo = $repo_base =~ $GITHUB;

    @args = ();

    if ($command =~ /^remote$/) {
        while (@_ > 0 && $_[0] =~ /^-/) {
            push(@args,shift);
        }
        if (@_ < 1) { help(1); }
        $subcommand = shift;
        if ($subcommand ne 'add' &&
            $subcommand ne 'rm' &&
            $subcommand ne 'set-branches' &&
            $subcommand ne 'set-url') {
            help(1);
        }
        while (@_ > 0 && $_[0] =~ /^-/) {
            push(@args,shift);
        }
        if (($subcommand eq 'add' || $subcommand eq 'rm') && @_ < 1) {
            help(1);
        } elsif (@_ < 1) { # set-url
            $branch_name = 'origin';
        } else {
            $branch_name = shift;
        }
    } elsif ($command eq 'new') {
        if (@_ < 1) {
            $branch_name = 'origin';
        } else {
            $branch_name = shift;
        }
    }

    push(@args, @_);

    # $doing is a good enough approximation to what we are doing that
    # we can use it to check that --resume is resuming the right command
    $doing = join(" ", ($command, @args));
    $started = 1;
    if ($try_to_resume && -f "resume") {
        my $what;
        open RESUME, "< resume"
            or die "Can't open resume file";
        $start_repo = <RESUME>;
        chomp $start_repo;
        $what = <RESUME>;
        chomp $what;
        close RESUME;
        if ($what eq $doing) {
            $started = 0;
        }
    }

    for $line (@packages) {
        $tag        = $$line{"tag"};
        # Use the "remote" structure for bare git repositories
        $localpath  = ($bare_flag) ?
                      $$line{"remotepath"} : $$line{"localpath"};
        $remotepath = ($checked_out_tree) ?
                      $$line{"localpath"}  : $$line{"remotepath"};

        if (!$started) {
            if ($start_repo eq $localpath) {
                $started = 1;
            }
            else {
                next;
            }
        }

        open RESUME, "> resume.tmp";
        print RESUME "$localpath\n";
        print RESUME "$doing\n";
        close RESUME;
        rename "resume.tmp", "resume";

        # We can't create directories on GitHub, so we translate
        # "packages/foo" into "package-foo".
        if ($is_github_repo) {
            $remotepath =~ s/\//-/;
        }

        # Construct the path for this package in the repo we pulled from
        $path = "$repo_base/$remotepath";

        if ($command eq "get") {
            next if $remotepath eq "-"; # "git submodule init/update" will get this later

            # Skip any repositories we have not included the tag for
            if (not defined($tags{$tag})) {
                $tags{$tag} = 0;
            }
            if ($tags{$tag} == 0) {
                next;
            }

            if (-d $localpath) {
                warning("$localpath already present; omitting")
                    if $localpath ne ".";
                &configure_repository($localpath);
                next;
            }

            # Note that we use "." as the path, as $localpath
            # doesn't exist yet.
            my @argsWithBare = @args;
            push @argsWithBare, $bare_flag if $bare_flag;
            &git(".", "clone", $path, $localpath, @argsWithBare);
            &configure_repository($localpath);
            next;
        }

        my $git_repo_present = 1 if -e "$localpath/.git" || ($bare_flag && -d "$localpath");
        if (not $git_repo_present) {
            if ($tag eq "") {
                die "Required repo $localpath is missing";
            }
            else {
                 message "== $localpath repo not present; skipping";
                 next;
            }
        }

        # Work out the arguments we should give to the SCM
        if ($command eq "status") {
            &git($localpath, $command, @args);
        }
        elsif ($command eq "commit") {
            # git fails if there is nothing to commit, so ignore failures
            $ignore_failure = 1;
            &git($localpath, "commit", @args);
        }
        elsif ($command eq "check_submodules") {
            # If we have a submodule then check whether it is up-to-date
            if ($remotepath eq "-") {
                my %remote_heads;

                message "== Checking sub-module $localpath";

                chdir($localpath);

                open my $lsremote, '-|', 'git', 'ls-remote', '--heads', '-q'
                    or die "Executing ls-remote failed: $!";
                while (<$lsremote>) {
                    if (/^([0-9a-f]{40})\s*refs\/heads\//) {
                        $remote_heads{$1} = 1;
                    }
                    else {
                        die "Bad output from ls-remote: $_";
                    }
                }
                close($lsremote);

                my $myhead = &readgitline('.', 'rev-parse', '--verify', 'HEAD');

                if (not defined($remote_heads{$myhead})) {
                    die "Sub module $localpath needs to be pushed; see http://ghc.haskell.org/trac/ghc/wiki/Repositories/Upstream";
                }
                
                chdir($initial_working_directory);
            }
        }
        elsif ($command eq "push") {
            # We don't automatically push to the submodules. If you want
            # to push to them then you need to use a special command, as
            # described on
            # http://ghc.haskell.org/trac/ghc/wiki/Repositories/Upstream
            if ($remotepath ne "-") {
                &git($localpath, "push", @args);
            }
        }
        elsif ($command eq "pull") {
            my $realcmd;
            my @realargs;
            if ($remotepath eq "-") {
                # Only fetch for the submodules. "git submodule update"
                # will take care of making us point to the right commit.
                $realcmd = "fetch";
                # we like "sync-all pull --rebase" to work:
                @realargs = grep(!/--rebase/,@args);
            }
            else {
                $realcmd = "pull";
                @realargs = @args;
            }
            &git($localpath, $realcmd, @realargs);
        }
        elsif ($command eq "new-workdir") {
            gitNewWorkdir ($localpath, @args);
        }
        elsif ($command eq "send") {
            $command = "send-email";
            &git($localpath, $command, @args);
        }
        elsif ($command eq "fetch") {
            &git($localpath, "fetch", @args);
        }
        elsif ($command eq "new") {
            my @scm_args = ("log", "$branch_name..");
            &git($localpath, @scm_args, @args);
        }
        elsif ($command eq "log") {
            &git($localpath, "log", @args);
        }
        elsif ($command eq "remote") {
            my @scm_args;
            my $rpath;
            $ignore_failure = 1;
            if ($remotepath eq '-') {
                $rpath = "$localpath.git"; # N.B.: $localpath lacks the .git suffix
                if ($localpath =~ m!^(?:libraries|utils)/!) {
                    # FIXME: This is just a simple heuristic to
                    # infer the remotepath for Git submodules. A
                    # proper solution would require to parse the
                    # .gitmodules file to obtain the actual
                    # localpath<->remotepath mapping.
                    $rpath =~ s!^(?:libraries|utils)/!packages/!;
                }
                $rpath = "$repo_base/$rpath";
            } else {
                $rpath = $path;
            }
            if ($subcommand eq 'add') {
                @scm_args = ("remote", "add", $branch_name, $rpath);
            } elsif ($subcommand eq 'rm') {
                @scm_args = ("remote", "rm", $branch_name);
            } elsif ($subcommand eq 'set-branches') {
                @scm_args = ("remote", "set-branches", $branch_name);
            } elsif ($subcommand eq 'set-url') {
                @scm_args = ("remote", "set-url", $branch_name, $rpath);
            }
            &git($localpath, @scm_args, @args);
        }
        elsif ($command eq "checkout") {
            # Not all repos are necessarily branched, so ignore failure
            $ignore_failure = 1;
            &git($localpath, "checkout", @args);
        }
        elsif ($command eq "grep") {
            # Hack around 'git grep' failing if there are no matches
            $ignore_failure = 1;
            &git($localpath, "grep", @args);
        }
        elsif ($command eq "diff") {
            &git($localpath, "diff", @args);
        }
        elsif ($command eq "clean") {
            &git($localpath, "clean", @args);
        }
        elsif ($command eq "reset") {
            &git($localpath, "reset", @args);
        }
        elsif ($command eq "branch") {
            &git($localpath, "branch", @args);
        }
        elsif ($command eq "config") {
            &git($localpath, "config", @args);
        }
        elsif ($command eq "repack") {
            &git($localpath, "repack", @args);
        }
        elsif ($command eq "format-patch") {
            &git($localpath, "format-patch", @args);
        }
        elsif ($command eq "gc") {
            &git($localpath, "gc", @args);
        }
        elsif ($command eq "tag") {
            &git($localpath, "tag", @args);
        }
        elsif ($command eq "compare") {
            # Don't compare the subrepos; it doesn't work properly as
            # they aren't on a branch.
            next if $remotepath eq "-";

            my $compareto;
            if ($#args eq -1) {
                $compareto = $path;
            }
            elsif ($#args eq 0) {
                $compareto = "$args[0]/$localpath";
            }
            elsif ($#args eq 1 && $args[0] eq "-b") {
                $compareto = "$args[1]/$remotepath";
            }
            else {
                die "Bad args for compare";
            }
            print "$localpath";
            print (' ' x (40 - length($localpath)));
            my $branch = &readgitline($localpath, "rev-parse", "--abbrev-ref", "HEAD");
            die "Bad branch: $branch"
                unless $branch =~ m!^[a-zA-Z][a-zA-Z0-9./-]*$!;
            my $us   = &readgitline(".", "ls-remote", $localpath, "refs/heads/$branch");
            my $them = &readgitline(".", "ls-remote", $compareto, "refs/heads/$branch");
            $us   =~ s/[[:space:]].*//;
            $them =~ s/[[:space:]].*//;
            die "Bad commit of mine: $us"     unless (length($us)   eq 40);
            die "Bad commit of theirs: $them" unless (length($them) eq 40);
            if ($us eq $them) {
                print "same\n";
            }
            else {
                print "DIFFERENT\n";
            }
        }
        else {
            die "Unknown command: $command";
        }
    }

    unlink "resume";
}

sub gitInitSubmodules {
    &git(".", "submodule", "init", @_);

    my ($repo_base, $checked_out_tree, $repo_local) = getrepo();

    my $submodulespaths = &readgit(".", "config", "--get-regexp", "^submodule[.].*[.]url");
    # if we came from github, change the urls appropriately
    while ($submodulespaths =~ m!^(submodule.(?:libraries|utils)/[a-zA-Z0-9]+.url) ($GITHUB)/ghc/packages/([a-zA-Z0-9]+).git$!gm) {
        &git(".", "config", $1, "$2/ghc/packages-$3");
    }

    # if we came from a local repository, grab our submodules from their
    # checkouts over there, if they exist.
    if ($repo_local) {
        while ($submodulespaths =~ m!^(submodule.((?:libraries|utils)/[a-zA-Z0-9]+).url) .*$!gm) {
            if (-e "$repo_base/$2/.git") {
                &git(".", "config", $1, "$repo_base/$2");
            }
        }
    }
}

sub checkCurrentBranchIsMaster {
    my $branch = `git symbolic-ref HEAD`;
    $branch =~ s/refs\/heads\///;
    $branch =~ s/\n//;

    if ($branch !~ /master/) {
        print "\nWarning: You are trying to 'pull' while on branch '$branch'.\n"
            . "Updates to this script will happen on the master branch which\n"
            . "means the version on this branch may be out of date.\n\n";
    }
}

sub help
{
        my $exit = shift;

        my $tags = join ' ', sort (grep !/^-$/, keys %tags);

        # Get the built in help
        my $help = <<END;
Usage:

./sync-all [-q] [-s] [--ignore-failure] [-r repo] [--checked-out] [--bare]
           [--<tag>] [--no-<tag>] [--resume]
           cmd [git flags]

    where <tag> is one of: $tags

Applies the command "cmd" to each repository in the tree.

A full repository tree is obtained by first cloning the ghc
repository, then getting the subrepositories with "sync-all get":

  \$ git clone http://git.haskell.org/ghc.git
  \$ cd ghc
  \$ ./sync-all get

After this, "./sync-all pull" will pull from the original repository
tree.

A remote pointing to another local repository tree can be added like
this:

  \$ ./sync-all -r /path/to/ghc remote add otherlocal

and then we can pull from this other tree with

  \$ ./sync-all pull otherlocal

-------------- Commands -----------------
get

    Clones all sub-repositories from the same place that the ghc
    repository was cloned from. See "which repos to use" below
    for details of how the subrepositories are laid out.

    There are various --<package-tag> options that can be given
    before "get" that enable extra repositories. The full list is
    given at the end of this help. For example:

    ./sync-all --nofib get

    would get the nofib repository in addition to the usual set of
    subrepositories.

remote add <remote-name>
remote rm <remote-name>
remote set-url [--push] <remote-name>

    Runs a "git remote" command on each subrepository, adjusting the
    repository location in each case appropriately. For example, to
    add a new remote pointing to the upstream repositories:

    ./sync-all -r http://git.haskell.org remote add upstream

    The -r flag points to the root of the repository tree (see "which
    repos to use" below). For a repository on the local filesystem it
    would point to the ghc repository, and for a remote repository it
    points to the directory containing "ghc.git".

compare
compare reporoot
compare -b reporoot

    Compare the git HEADs of the repos to the origin repos, or the
    repos under reporoot (which is assumde to be a checked-out tree
    unless the -b flag is used).

    1 line is printed for each repo, indicating whether the repo is
    at the "same" or a "DIFFERENT" commit.

These commands just run the equivalent git command on each repository, passing
any extra arguments to git:

  branch
  checkout
  clean
  commit
  config
  diff
  fetch
  format-patch
  gc
  grep
  log
  new
  new-workdir
  pull
  push
  repack
  reset
  send
  status
  tag

-------------- Flags -------------------
These flags are given *before* the command and modify the way sync-all behaves.
Flags given *after* the command are passed to git.

  -q says to be quiet, and -s to be silent.

  --resume will restart a command that failed, from the repo at which it
  failed. This means you don't need to wait while, e.g., "pull" goes through
  all the repos it's just pulled, and tries to pull them again.

  --ignore-failure says to ignore errors and move on to the next repository

  -r repo says to use repo as the location of package repositories

  --checked-out says that the remote repo is in checked-out layout, as opposed
  to the layout used for the main repo. By default a repo on the local
  filesystem is assumed to be checked-out, and repos accessed via HTTP or SSH
  are assumed to be in the main repo layout; use --checked-out to override the
  latter.

  --bare says that the local repo is in bare layout, same as the main repo. It
  also means that these repos are bare. You only have to use this flag if you
  don't have a bare ghc.git in the current directory and would like to 'get'
  all of the repos bare. Requires packages.conf to be present in the current
  directory (a renamed packages file from the main ghc repo).

  Note: --checked-out and --bare flags are NOT the opposite of each other.
        --checked-out: describes the layout of the remote repository tree.
        --bare:        describes the layout of the local repository tree.

  --nofib also clones the nofib benchmark suite

  --extra also clone some extra library packages

  --no-dph avoids cloning the dph packages


------------ Checking out a branch -------------
To check out a branch you can run the following command:

  \$ ./sync-all checkout ghc-7.4


------------ Which repos to use -------------
sync-all uses the following algorithm to decide which remote repos to use

It always computes the remote repos from a single base, <repo_base> How is
<repo_base> set? If you say "-r repo", then that's <repo_base> otherwise
<repo_base> is set by asking git where the ghc repo came from, and removing the
last component (e.g. /ghc.git/ or /ghc/).

Then sync-all iterates over the package found in the file ./packages; see that
file for a description of the contents.

If <repo_base> looks like a local filesystem path, or if you give the
--checked-out flag, sync-all works on repos of form:

  <repo_base>/<local-path>

otherwise sync-all works on repos of form:

  <repo_base>/<remote-path>

This logic lets you say
  both    sync-all -r http://example.org/ghc-6.12 remote add ghc-6.12
  and     sync-all -r ../working remote add working
The latter is called a "checked-out tree".

sync-all *ignores* the defaultrepo of all repos other than the root one. So the
remote repos must be laid out in one of the two formats given by <local-path>
and <remote-path> in the file 'packages'.

Available package-tags are:
END

        # Collect all the tags in the packages file
        my %available_tags;
        open IN, "< packages.conf"
            or open IN, "< packages" # clashes with packages directory when using --bare
            or die "Can't open packages file (or packages.conf)";
        while (<IN>) {
            chomp;
            if (/^([^# ]+) +(?:([^ ]+) +)?([^ ]+) +([^ ]+)/) {
                if (defined($2) && $2 ne "-") {
                    $available_tags{$2} = 1;
                }
            }
            elsif (! /^(#.*)?$/) {
                die "Bad line: $_";
            }
        }
        close IN;

        # Show those tags and the help text
        my @available_tags = keys %available_tags;
        print "$help@available_tags\n\n";
        exit $exit;
}

sub main {

    &parsePackages();

    $tags{"-"} = 1;
    $tags{"dph"} = 1;
    if ($OSNAME =~ /^(MSWin32|Cygwin|msys)$/) {
        $tags{"windows"} = 1;
    }

    while ($#_ ne -1) {
        my $arg = shift;
        # We handle -q here as well as lower down as we need to skip over it
        # if it comes before the source-control command
        if ($arg eq "-q") {
            $verbose = 1;
        }
        elsif ($arg eq "-s") {
            $verbose = 0;
        }
        elsif ($arg eq "-r") {
            $defaultrepo = shift;
        }
        elsif ($arg eq "--resume") {
            $try_to_resume = 1;
        }
        elsif ($arg eq "--ignore-failure") {
            $ignore_failure = 1;
        }
        elsif ($arg eq "--complete" || $arg eq "--partial") {
            $get_mode = $arg;
        }
        # Use --checked-out if the _remote_ repos are a checked-out tree,
        # rather than the master trees.
        elsif ($arg eq "--checked-out") {
            $checked_out_flag = 1;
        }
        # Use --bare if the _local_ repos are bare repos,
        # rather than a checked-out tree.
        elsif ($arg eq "--bare") {
            $bare_flag = $arg;
        }
        elsif ($arg eq "--help") {
            help(0);
        }
        # --<tag> says we grab the libs tagged 'tag' with
        # 'get'. It has no effect on the other commands.
        elsif ($arg =~ m/^--no-(.*)$/ && defined($tags{$1})) {
            $tags{$1} = 0;
        }
        elsif ($arg =~ m/^--(.*)$/ && defined($tags{$1})) {
            $tags{$1} = 1;
        }
        elsif ($arg =~ m/^-/) {
            die "Unrecognised flag: $arg";
        }
        else {
            unshift @_, $arg;
            if (grep /^-q$/, @_) {
                $verbose = 1;
            }
            last;
        }
    }

    # check for ghc repositories in cwd
    my $checked_out_found = 1 if (-d ".git" && -d "compiler");
    my $bare_found = 1 if (-d "ghc.git");

    if ($bare_flag && ! $bare_found && ! $defaultrepo) {
        die "error: bare repository ghc.git not found.\n"
          . "       Either clone a bare ghc repo first or specify the repo location. E.g.:\n"
          . "       ./sync-all --bare [--nofib --extra] -r http://git.haskell.org get\n"
    }
    elsif ($bare_found) {
        $bare_flag = "--bare";
    }
    elsif (! $bare_flag && ! $checked_out_found) {
        die "error: sync-all must be run from the top level of the ghc tree.";
    }

    if ($#_ eq -1) {
        help(1);
    }
    else {
        # Give the command and rest of the arguments to the main loop
        # We normalise command names here to avoid duplicating the
        # abbreviations that we allow.
        my $command = shift;

        if ($command =~ /^(?:g|ge|get)$/) {
            $command = "get";
        }
        elsif ($command =~ /^(?:pus|push)$/) {
            $command = "push";
        }
        elsif ($command =~ /^(?:pul|pull)$/) {
            $command = "pull";
        }
        elsif ($command =~ /^(?:s|se|sen|send)$/) {
            $command = "send";
        }
        elsif ($command =~ /^(?:w|wh|wha|what|whats|whatsn|whatsne|whatsnew|status)$/) {
            $command = "status";
        }

        if ($command eq "push") {
            &gitall("check_submodules", @_);
        }

        &gitall($command, @_);

        my @submodule_args = grep(/^-q/,@_);

        if ($command eq "get") {
            &gitInitSubmodules(@submodule_args);
        }

        if ($command eq "pull") {
            my $gitConfig = &tryReadFile(".git/config");
            if ($gitConfig !~ /submodule/) {
                &gitInitSubmodules(@submodule_args);
            }
        }
        if ($command eq "get" or $command eq "pull") {
            my $gitConfig = &tryReadFile(".git/config");
            if ($gitConfig !~ /submodule/) {
                &gitInitSubmodules(@submodule_args);
            }
            &git(".", "submodule", "update", @submodule_args);
        }
    }
}

BEGIN {
    my %argvHash = map { $_, 1 } @ARGV;
    if ($argvHash {"pull"}) {
        checkCurrentBranchIsMaster();
    }
    $initial_working_directory = getcwd();

    $SIG{__DIE__} = sub {
      die @_ if $^S;
      $exit_via_die = 1;
    };

    my @obsolete_dirs = qw!
        testsuite
        libraries/base
        libraries/ghc-prim
        libraries/template-haskell
        libraries/integer-gmp
        libraries/integer-simple
        !;
    for my $dir (@obsolete_dirs) {
        if (-d "$dir/.git") {
            print <<EOF;
============================
ATTENTION!

You have a left-over $dir/.git folder in your GHC tree!

Please backup or remove it (e.g. "rm -r $dir/.git") before
proceeding as the aforesaid Git repository is now tracked as part of
the ghc Git repository (see #8545 for more details)
============================
EOF
            die "detected obsolete $dir/.git folder"
        }
    }
}

END {
    return if $exit_via_die;
    my $ec = $?;

    chdir($initial_working_directory);

    my @obsolete_dirs = (
        ["utils/haddock",    "87e2ca11c3d1b1bc49900fba0b5c5c6f85650718"],
        ["libraries/binary", "749ac0efbde3b14901417364a872796598747aaf"],
        ["libraries/mtl",    "c67d8f7247c612dc35242bc67e616f7ea35eadb9"],
        ["libraries/Cabal",  "c8ebd66a32865f72ae03ee0663c62df3d77f08fe"],
        );
    for (@obsolete_dirs) {
        my ($dir, $hash) = $_;
        my $name = $dir =~ m!/([^/]+)$!;
        message "== Checking for old $name repo";
        if (-d "$dir/.git") {
            chdir($dir);
            if ((system "git log -1 $hash > /dev/null 2> /dev/null") == 0) {
                print <<EOF;
============================
ATTENTION!

You have an old $name repository in your GHC tree!

Please remove it (e.g. "rm -r $dir"), and then run
"./sync-all get" to get the new repository.
============================
EOF
            }
            chdir($initial_working_directory);
        }
    }
    message "== Checking for old time from tarball";
    if (-d "libraries/time" and ! -e "libraries/time/.git") {
            print <<EOF;
============================
ATTENTION!

You have an old time package in your GHC tree!

Please remove it (e.g. "rm -r libraries/time"), and then run
"./sync-all get" to get the new repository.
============================
EOF
    }

    message "== Checking for obsolete Git repo URL";
    my $repo_url = &readgitline(".", 'config', '--get', 'remote.origin.url');
    if ($repo_url =~ /^http:\/\/darcs.haskell.org/) {
            print <<EOF;
============================
ATTENTION!

You seem to be using obsolete Git repository URLs.

Please run

  ./sync-all -r git://git.haskell.org remote set-url

or (in case port 9418/tcp is filtered by your firewall)

  ./sync-all -r http://git.haskell.org remote set-url

to update your local checkout to use the new Git URLs.
============================
EOF
    }

    $? = $ec;
}

main(@ARGV);