editpage: Avoid storing accidental state changes when previewing pages.

This is a slow, safe, stupid approach. Could make deep copies of the data
structures as backups instead of re-loading the index from disk.

IkiWiki/Plugin/editpage.pm

@@ -170,10 +170,8 @@ sub cgi_editpage ($$) {
 		$previewing=1;
 
 		my $new=not exists $pagesources{$page};
-		if ($new) {
-			# temporarily record its type
-			$pagesources{$page}=$page.".".$type;
-		}
+		# temporarily record its type
+		$pagesources{$page}=$page.".".$type if $new;
 		my %wasrendered=map { $_ => 1 } @{$renderedfiles{$page}};
 
 		my $content=$form->field('editcontent');
@@ -198,18 +196,17 @@ sub cgi_editpage ($$) {
 		});
 		$form->tmpl_param("page_preview", $preview);
 		
-		if ($new) {
-			delete $pagesources{$page};
-		}
-
 		# Previewing may have created files on disk.
 		# Keep a list of these to be deleted later.
 		my %previews = map { $_ => 1 } @{$wikistate{editpage}{previews}};
 		foreach my $f (@{$renderedfiles{$page}}) {
 			$previews{$f}=1 unless $wasrendered{$f};
 		}
+
+		# Throw out any other state changes made during previewing,
+		# and save the previews list.
+		loadindex();
 		@{$wikistate{editpage}{previews}} = keys %previews;
-		$renderedfiles{$page}=[keys %wasrendered];
 		saveindex();
 	}
 	elsif ($form->submitted eq "Save Page") {

debian/changelog

@@ -8,6 +8,7 @@ ikiwiki (3.20100609) unstable; urgency=low
   * Fix support for globbing in tagged() pagespecs.
   * Fix display of sidebar when previewing page edit. (Thanks, privat)
   * relativedate: Fix problem with localised dates not working.
+  * editpage: Avoid storing accidental state changes when previewing pages.
 
  -- Joey Hess <joeyh@debian.org>  Mon, 31 May 2010 20:44:17 -0400
 

doc/bugs/comments_preview_unsafe_with_allowdirectives.mdwn

@@ -0,0 +1,8 @@
+If `comments_allowdirectives` is set, previewing a comment can run
+directives that create files. (Eg, img.) Unlike editpage, it does not
+keep track of those files and expire them. So the files will linger in
+destdir forever.
+
+Probably when the user then tries to save the comment, ikiwiki will refuse
+to overwrite the unknown file, and will crash.
+--[[Joey]]

doc/bugs/preview_pagestate.mdwn

@@ -9,3 +9,5 @@ saves other state changes.
 
 Seems like it needs to isolate all state changes when previewing... ugh.
 --[[Joey]] 
+
+[[done]]