pagespec error/failure distinction and error display by inline

* Add IkiWiki::ErrorReason objects, and modify pagespecs to return
  them in cases where they fail to match due to a configuration or syntax
  error.
* inline: Display a handy error message if the inline cannot display any
  pages due to such an error.

This is perhaps somewhat incomplete, as other users of pagespecs do not
display the error, and will eventually need similar modifications to inline.
I should probably factor out a pagespec_match_all function and make it throw
ErrorReasons.

2 files changed, 17 insertions, 10 deletions

diff --git a/IkiWiki/Plugin/filecheck.pm b/IkiWiki/Plugin/filecheck.pm
index 8575ee108..01d490961 100644
--- a/IkiWiki/Plugin/filecheck.pm
+++ b/IkiWiki/Plugin/filecheck.pm
@@ -71,13 +71,13 @@ sub match_maxsize ($$;@) {
 	my $page=shift;
 	my $maxsize=eval{IkiWiki::Plugin::filecheck::parsesize(shift)};
 	if ($@) {
-		return IkiWiki::FailReason->new("unable to parse maxsize (or number too large)");
+		return IkiWiki::ErrorReason->new("unable to parse maxsize (or number too large)");
 	}
 
 	my %params=@_;
 	my $file=exists $params{file} ? $params{file} : $IkiWiki::pagesources{$page};
 	if (! defined $file) {
-		return IkiWiki::FailReason->new("no file specified");
+		return IkiWiki::ErrorReason->new("no file specified");
 	}
 
 	if (-s $file > $maxsize) {
@@ -92,13 +92,13 @@ sub match_minsize ($$;@) {
 	my $page=shift;
 	my $minsize=eval{IkiWiki::Plugin::filecheck::parsesize(shift)};
 	if ($@) {
-		return IkiWiki::FailReason->new("unable to parse minsize (or number too large)");
+		return IkiWiki::ErrorReason->new("unable to parse minsize (or number too large)");
 	}
 
 	my %params=@_;
 	my $file=exists $params{file} ? $params{file} : $IkiWiki::pagesources{$page};
 	if (! defined $file) {
-		return IkiWiki::FailReason->new("no file specified");
+		return IkiWiki::ErrorReason->new("no file specified");
 	}
 
 	if (-s $file < $minsize) {
@@ -116,14 +116,14 @@ sub match_mimetype ($$;@) {
 	my %params=@_;
 	my $file=exists $params{file} ? $params{file} : $IkiWiki::pagesources{$page};
 	if (! defined $file) {
-		return IkiWiki::FailReason->new("no file specified");
+		return IkiWiki::ErrorReason->new("no file specified");
 	}
 
 	# Use ::magic to get the mime type, the idea is to only trust
 	# data obtained by examining the actual file contents.
 	eval q{use File::MimeInfo::Magic};
 	if ($@) {
-		return IkiWiki::FailReason->new("failed to load File::MimeInfo::Magic ($@); cannot check MIME type");
+		return IkiWiki::ErrorReason->new("failed to load File::MimeInfo::Magic ($@); cannot check MIME type");
 	}
 	my $mimetype=File::MimeInfo::Magic::magic($file);
 	if (! defined $mimetype) {
@@ -149,12 +149,12 @@ sub match_virusfree ($$;@) {
 	my %params=@_;
 	my $file=exists $params{file} ? $params{file} : $IkiWiki::pagesources{$page};
 	if (! defined $file) {
-		return IkiWiki::FailReason->new("no file specified");
+		return IkiWiki::ErrorReason->new("no file specified");
 	}
 
 	if (! exists $IkiWiki::config{virus_checker} ||
 	    ! length $IkiWiki::config{virus_checker}) {
-		return IkiWiki::FailReason->new("no virus_checker configured");
+		return IkiWiki::ErrorReason->new("no virus_checker configured");
 	}
 
 	# The file needs to be fed into the virus checker on stdin,
@@ -162,7 +162,7 @@ sub match_virusfree ($$;@) {
 	# used, clamd would fail to read it.
 	eval q{use IPC::Open2};
 	error($@) if $@;
-	open (IN, "<", $file) || return IkiWiki::FailReason->new("failed to read file");
+	open (IN, "<", $file) || return IkiWiki::ErrorReason->new("failed to read file");
 	binmode(IN);
 	my $sigpipe=0;
 	$SIG{PIPE} = sub { $sigpipe=1 };
diff --git a/IkiWiki/Plugin/inline.pm b/IkiWiki/Plugin/inline.pm
index 9d7d4b0fd..551c38a65 100644
--- a/IkiWiki/Plugin/inline.pm
+++ b/IkiWiki/Plugin/inline.pm
@@ -184,13 +184,20 @@ sub preprocess_inline (@) {
 	}
 
 	my @list;
+	my $lastmatch;
 	foreach my $page (keys %pagesources) {
 		next if $page eq $params{page};
-		if (pagespec_match($page, $params{pages}, location => $params{page})) {
+		$lastmatch=pagespec_match($page, $params{pages}, location => $params{page});
+		if ($lastmatch) {
 			push @list, $page;
 		}
 	}
 
+	if (! @list && defined $lastmatch &&
+	    $lastmatch->isa("IkiWiki::ErrorReason")) {
+		error(sprintf(gettext("cannot match pages: %s"), $lastmatch));
+	}
+
 	if (exists $params{sort} && $params{sort} eq 'title') {
 		@list=sort { pagetitle(basename($a)) cmp pagetitle(basename($b)) } @list;
 	}