po: Add support for mo files in underlays

In order to support translated basewiki and other underlays, we need
support for mo files in underlays.

The code did not allow this before, because if a mo file was in an
underlay, then it might try to update it, and its pot, and write to the
underlay, which is guaranteed to either fail due to permissions, or be
undesirable.

To fix, my approach is to just detect if a mo or pot file that is about to
be updated is in an underlay, and skip updating it. This seems to work
well:

- If the mo is out of date in the underlay, it won't get updated, but this
  would probably be due to a problem in the underlay, or more likely,
  the wiki is being rebuilt and so it *thinks* the mo is out of date,
  but it's really not (and it would be a waste of time to rebuild it
  anyway).
- If a page from the basewiki is edited, it is saved to the srcdir,
  which causes generation of an updated mo and pot also in the srcdir;
  the underlay stops being used for that page, and everything seems
  to work.

Note that I am not including an underlay search directory for pot files.
They *seem* to be unnecessary for the underlay, since the mo files
in there never need to be updated.

1 files changed, 29 insertions, 13 deletions

diff --git a/IkiWiki/Plugin/po.pm b/IkiWiki/Plugin/po.pm
index 124164da7..cf801c827 100644
--- a/IkiWiki/Plugin/po.pm
+++ b/IkiWiki/Plugin/po.pm
@@ -151,11 +151,24 @@ sub checkconfig () {
 
 	push @{$config{wiki_file_prune_regexps}}, qr/\.pot$/;
 
-	if ($config{po_master_language}{code} ne 'en') {
-		# use translated underlay directories in preference
-		# to the untranslated ones
-		foreach my $underlay ('basewiki', reverse @{$config{underlaydirs}}) {
-			add_underlay("locale/".$config{po_master_language}{code}."/".$underlay);
+	# Translated versions of the underlays are added if available.
+	foreach my $underlay ("basewiki", map { m/^\Q$config{underlaydirbase}\E\/*(.*)/ } reverse @{$config{underlaydirs}}) {
+		next if $underlay=~/^locale\//;
+
+		# Add underlay containing the pot files.
+		#add_underlay("locale/pot/$underlay")
+		#		if -d "$config{underlaydirbase}/locale/pot/$underlay";
+
+		# Add underlays containing the po files for slave languages.
+		foreach my $ll (keys %{$config{po_slave_languages}}) {
+			add_underlay("locale/mo/$underlay")
+				if -d "$config{underlaydirbase}/locale/mo/$underlay";
+		}
+	
+		if ($config{po_master_language}{code} ne 'en') {
+			# Add underlay containing translated source files
+			# for the master language.
+			add_underlay("locale/$config{po_master_language}{code}/$underlay");
 		}
 	}
 }
@@ -377,22 +390,26 @@ sub change (@) {
 	my $updated_po_files=0;
 
 	# Refresh/create POT and PO files as needed.
+	# (But avoid doing so if they are in an underlay directory.)
 	foreach my $file (grep {istranslatablefile($_)} @rendered) {
-		my $page=pagename($file);
 		my $masterfile=srcfile($file);
+		my $page=pagename($file);
 		my $updated_pot_file=0;
-		# Only refresh Pot file if it does not exist, or if
+		# Only refresh POT file if it does not exist, or if
 		# $pagesources{$page} was changed: don't if only the HTML was
 		# refreshed, e.g. because of a dependency.
-		if ((grep { $_ eq $pagesources{$page} } @origneedsbuild)
-		    || ! -e potfile($masterfile)) {
+		if ($masterfile eq "$config{srcdir}/$file" &&
+		   ((grep { $_ eq $pagesources{$page} } @origneedsbuild)
+		    || ! -e potfile($masterfile))) {
 			refreshpot($masterfile);
 			$updated_pot_file=1;
 		}
 		my @pofiles;
-		map {
-			push @pofiles, $_ if ($updated_pot_file || ! -e $_);
-		} (pofiles($masterfile));
+		foreach my $po (pofiles($masterfile)) {
+			next if ! $updated_pot_file && ! -e $po;
+			next if grep { $po=~/\Q$_\E/ } @{$config{underlaydirs}};
+			push @pofiles, $po;
+		}
 		if (@pofiles) {
 			refreshpofiles($masterfile, @pofiles);
 			map { IkiWiki::rcs_add($_) } @pofiles if $config{rcs};
@@ -666,7 +683,6 @@ sub istranslatablefile ($) {
 	my $type=pagetype($file);
 	return 0 if ! defined $type || $type eq 'po';
 	return 0 if $file =~ /\.pot$/;
-	return 0 unless -e "$config{srcdir}/$file"; # underlay dirs may be read-only
 	return 1 if pagespec_match(pagename($file), $config{po_translatable_pages});
 	return;
 }