git-svn: ensure we're at the top-level and can access $GIT_DIR

If we are run inside a subdirectory of a working tree, we'll
chdir to the top first before touching anything.  This also
prevents the accidental creation of .git directories inside
subdirectories since they need metadata.

Noticed by maio on #git

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

diff --git a/git-svn.perl b/git-svn.perl
index b4e8966919e67bc8aff3235aa2cd3da706dc928a..a6d98f1608f7a98d3368697717df380f2250686c 100755 (executable)
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -9,6 +9,7 @@ use vars qw/    $AUTHOR $VERSION
 $AUTHOR = 'Eric Wong <normalperson@yhbt.net>';
 $VERSION = '@@GIT_VERSION@@';
 
+my $git_dir_user_set = 1 if defined $ENV{GIT_DIR};
 $ENV{GIT_DIR} ||= '.git';
 $Git::SVN::default_repo_id = 'svn';
 $Git::SVN::default_ref_id = $ENV{GIT_SVN_ID} || 'git-svn';
@@ -178,6 +179,28 @@ usage(0) if $_help;
 version() if $_version;
 usage(1) unless defined $cmd;
 load_authors() if $_authors;
+
+# make sure we're always running
+unless ($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};
+               chomp(my $cdup = command_oneline(qw/rev-parse --show-cdup/));
+               unless (length $cdup) {
+                       die "Already at toplevel, but $git_dir ",
+                           "not found '$cdup'\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} = $git_dir;
+       }
+}
 unless ($cmd =~ /^(?:clone|init|multi-init|commit-diff)$/) {
        Git::SVN::Migration::migration_check();
 }