prune: do not prune beyond an optional base directory, and add a test

Previously, prune("wiki/srcdir/sandbox/test.mdwn") could delete srcdir
or even wiki, if they happened to be empty. This is rarely what you
want: there's usually some base directory (destdir, srcdir, transientdir
or another subdirectory of wikistatedir) beyond which you do not want to
delete.

IkiWiki/Plugin/aggregate.pm

@@ -201,7 +201,7 @@ sub migrate_to_internal {
 		if (-e $oldoutput) {
 			require IkiWiki::Render;
 			debug("removing output file $oldoutput");
-			IkiWiki::prune($oldoutput);
+			IkiWiki::prune($oldoutput, $config{destdir});
 		}
 	}
 	

IkiWiki/Plugin/amazon_s3.pm

@@ -232,8 +232,9 @@ sub writefile ($$$;$$) {
 }
 
 # This is a wrapper around the real prune.
-sub prune ($) {
+sub prune ($;$) {
 	my $file=shift;
+	my $up_to=shift;
 
 	my @keys=IkiWiki::Plugin::amazon_s3::file2keys($file);
 
@@ -250,7 +251,7 @@ sub prune ($) {
 		}
 	}
 
-	return $IkiWiki::Plugin::amazon_s3::subs{'IkiWiki::prune'}->($file);
+	return $IkiWiki::Plugin::amazon_s3::subs{'IkiWiki::prune'}->($file, $up_to);
 }
 
 1

IkiWiki/Plugin/attachment.pm

@@ -286,7 +286,7 @@ sub attachments_save {
 	}
 	return unless @attachments;
 	require IkiWiki::Render;
-	IkiWiki::prune($dir);
+	IkiWiki::prune($dir, $config{wikistatedir}."/attachments");
 
 	# Check the attachments in and trigger a wiki refresh.
 	if ($config{rcs}) {

IkiWiki/Plugin/comments.pm

@@ -665,9 +665,11 @@ sub commentmoderation ($$) {
 
 				my $page=IkiWiki::dirname($f);
 				my $file="$config{srcdir}/$f";
+				my $filedir="$config{srcdir}";
 				if (! -e $file) {
 					# old location
 					$file="$config{wikistatedir}/comments_pending/".$f;
+					$filedir="$config{wikistatedir}/comments_pending";
 				}
 
 				if ($action eq 'Accept') {
@@ -682,7 +684,7 @@ sub commentmoderation ($$) {
 				}
 
 				require IkiWiki::Render;
-				IkiWiki::prune($file);
+				IkiWiki::prune($file, $filedir);
 			}
 		}
 

IkiWiki/Plugin/editpage.pm

@@ -39,7 +39,7 @@ sub refresh () {
 				}
 				if ($delete) {
 					debug(sprintf(gettext("removing old preview %s"), $file));
-					IkiWiki::prune("$config{destdir}/$file");
+					IkiWiki::prune("$config{destdir}/$file", $config{destdir});
 				}
 			}
 			elsif (defined $mtime) {

IkiWiki/Plugin/po.pm

@@ -1102,7 +1102,7 @@ sub deletetranslations ($) {
 			IkiWiki::rcs_remove($_);
 		}
 		else {
-			IkiWiki::prune("$config{srcdir}/$_");
+			IkiWiki::prune("$config{srcdir}/$_", $config{srcdir});
 		}
 	} @todelete;
 

IkiWiki/Plugin/remove.pm

@@ -124,7 +124,7 @@ sub removal_confirm ($$@) {
 			my $f=IkiWiki::Plugin::attachment::is_held_attachment($page);
 			if (defined $f) {
 				require IkiWiki::Render;
-				IkiWiki::prune($f);
+				IkiWiki::prune($f, "$config{wikistatedir}/attachments");
 			}
 		}
 	}
@@ -235,7 +235,7 @@ sub sessioncgi ($$) {
 			}
 			else {
 				foreach my $file (@files) {
-					IkiWiki::prune("$config{srcdir}/$file");
+					IkiWiki::prune("$config{srcdir}/$file", $config{srcdir});
 				}
 			}
 			IkiWiki::refresh();

IkiWiki/Plugin/transient.pm

@@ -43,7 +43,7 @@ sub rendered (@) {
 		my $casualty = "$transientdir/$file";
 		if (srcfile($file) ne $casualty && -e $casualty) {
 			debug(sprintf(gettext("removing transient version of %s"), $file));
-			IkiWiki::prune($casualty);
+			IkiWiki::prune($casualty, $transientdir);
 		}
 	}
 }

IkiWiki/Render.pm

@@ -262,12 +262,13 @@ sub render ($$) {
 	}
 }
 
-sub prune ($) {
+sub prune ($;$) {
 	my $file=shift;
+	my $up_to=shift;
 
 	unlink($file);
 	my $dir=dirname($file);
-	while (rmdir($dir)) {
+	while ((! defined $up_to || $dir =~ m{^\Q$up_to\E\/}) && rmdir($dir)) {
 		$dir=dirname($dir);
 	}
 }
@@ -447,7 +448,7 @@ sub remove_del (@) {
 		}
 	
 		foreach my $old (@{$oldrenderedfiles{$page}}) {
-			prune($config{destdir}."/".$old);
+			prune($config{destdir}."/".$old, $config{destdir});
 		}
 
 		foreach my $source (keys %destsources) {
@@ -537,7 +538,7 @@ sub remove_unrendered () {
 		foreach my $file (@{$oldrenderedfiles{$page}}) {
 			if (! grep { $_ eq $file } @{$renderedfiles{$page}}) {
 				debug(sprintf(gettext("removing %s, no longer built by %s"), $file, $page));
-				prune($config{destdir}."/".$file);
+				prune($config{destdir}."/".$file, $config{destdir});
 			}
 		}
 	}
@@ -844,7 +845,7 @@ sub clean_rendered {
 	remove_unrendered();
 	foreach my $page (keys %oldrenderedfiles) {
 		foreach my $file (@{$oldrenderedfiles{$page}}) {
-			prune($config{destdir}."/".$file);
+			prune($config{destdir}."/".$file, $config{destdir});
 		}
 	}
 }

t/prune.t

@@ -0,0 +1,23 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use Test::More tests => 6;
+use File::Path qw(make_path remove_tree);
+
+BEGIN { use_ok("IkiWiki"); }
+BEGIN { use_ok("IkiWiki::Render"); }
+
+%config=IkiWiki::defaultconfig();
+
+remove_tree("t/tmp");
+
+make_path("t/tmp/srcdir/a/b/c");
+make_path("t/tmp/srcdir/d/e/f");
+writefile("a/b/c/d.mdwn", "t/tmp/srcdir", "foo");
+writefile("d/e/f/g.mdwn", "t/tmp/srcdir", "foo");
+IkiWiki::prune("t/tmp/srcdir/d/e/f/g.mdwn");
+ok(-d "t/tmp/srcdir");
+ok(! -e "t/tmp/srcdir/d");
+IkiWiki::prune("t/tmp/srcdir/a/b/c/d.mdwn", "t/tmp/srcdir");
+ok(-d "t/tmp/srcdir");
+ok(! -e "t/tmp/srcdir/a");