-our $clean_using_builder;
-# ^ tree is to be cleaned by dpkg-source's builtin idea that it should
-# clean the tree before building (perhaps invoked indirectly by
-# whatever we are using to run the build), rather than separately
-# and explicitly by us.
+sub clean_tree_check_git ($$) {
+ my ($honour_ignores, $message) = @_;
+ my @cmd = (@git, qw(clean -dn));
+ push @cmd, qw(-x) unless $honour_ignores;
+ my $leftovers = cmdoutput @cmd;
+ if (length $leftovers) {
+ print STDERR $leftovers, "\n" or confess $!;
+ fail $message;
+ }
+}
+
+sub clean_tree_check_git_wd ($) {
+ my ($message) = @_;
+ return if $cleanmode =~ m{no-check};
+ return if $patches_applied_dirtily; # yuk
+ clean_tree_check_git +($cleanmode !~ m{all-check}),
+ (f_ <<END, $message);
+%s
+If this is just missing .gitignore entries, use a different clean
+mode, eg --clean=dpkg-source,no-check (-wdu/-wddu) to ignore them
+or --clean=git (-wg/-wgf) to use \`git clean' instead.
+END
+}
+
+sub clean_tree_check () {
+ # Not yet fully implemented.
+ # This function needs to not care about modified but tracked files.
+ # That was done by check_not_dirty, and by now we may have run
+ # the rules clean target which might modify tracked files (!)
+ if ($cleanmode =~ m{^check}) {
+ clean_tree_check_git +($cleanmode =~ m{ignores}), __
+ "tree contains uncommitted files and --clean=check specified";
+ } elsif ($cleanmode =~ m{^dpkg-source}) {
+ clean_tree_check_git_wd __
+ "tree contains uncommitted files (NB dgit didn't run rules clean)";
+ }
+}