Don't emit a warning when provided an empty tag list in YFM

This fixes #426

NEWS

@@ -25,6 +25,8 @@ Tex:
 
 Markdown:
  * Treat link reference definitions as no-wrap (GitHub's #422) [gemmaro].
+ * Don't emit a warning when provided an empty tag list in YFM
+   (GitHub's #426) [Martin].
 
 General:
  * Don't fail on empty po files, e.g. adoc files containing only

lib/Locale/Po4a/TransTractor.pm

@@ -1308,9 +1308,15 @@ sub handle_yaml {
         my ( $self, $is_yfm, $blockref, $hash, $indent, $ctx, $yfm_keys, $yfm_skip_array, $yfm_paths ) = @_;
 
         foreach my $name ( sort keys %$hash ) {
-            my $el     = $hash->{$name};
+            my $el     = $hash->{$name} // "";
             my $header = ( '  ' x $indent ) . YAML::Tiny::_dump_scalar( "dummy", $name, 1 ) . ":";
-            my $type   = ref $el;
+
+            unless ( length($el) > 0 ) {    # empty element, as in "tags: " with nothing after the column
+                $self->pushline( $header . "\n" );
+                next;
+            }
+
+            my $type = ref $el;
             if ( !$type ) {
                 my %keys  = %{$yfm_keys};
                 my %paths = %{$yfm_paths};

t/fmt/txt-markdown/YamlFrontMatter_KeysPaths.md

@@ -6,6 +6,7 @@ numeric_ignored_value: 22
 tags:
 - yaml
 - markdown
+emptytag:
 people:
   - 
     name: John D'vloper

t/fmt/txt-markdown/YamlFrontMatter_KeysPaths.norm

@@ -1,5 +1,6 @@
 ---
 author: test
+emptytag:
 numeric_ignored_value: 22
 paragraph: "Some text to translate, please.\n"
 people:

t/fmt/txt-markdown/YamlFrontMatter_KeysPaths.po

@@ -35,13 +35,13 @@ msgid "I mean: why not?"
 msgstr "I MEAN: WHY NOT?"
 
 #. type: Title #
-#: YamlFrontMatter_KeysPaths.md:28
+#: YamlFrontMatter_KeysPaths.md:29
 #, no-wrap
 msgid "YAML: does it fit in Markdown?"
 msgstr "YAML: DOES IT FIT IN MARKDOWN?"
 
 #. type: Plain text
-#: YamlFrontMatter_KeysPaths.md:32
+#: YamlFrontMatter_KeysPaths.md:33
 msgid ""
 "Lots of Static Site Generators like Jekyll, Hugo, Lektor and more use a "
 "standard format: Markdown with YAML Front Matter."
@@ -50,11 +50,11 @@ msgstr ""
 "STANDARD FORMAT: MARKDOWN WITH YAML FRONT MATTER."
 
 #. type: Plain text
-#: YamlFrontMatter_KeysPaths.md:34
+#: YamlFrontMatter_KeysPaths.md:35
 msgid "Why"
 msgstr "WHY"
 
 #. type: Plain text
-#: YamlFrontMatter_KeysPaths.md:37
+#: YamlFrontMatter_KeysPaths.md:38
 msgid "Because blog posts need metadata!"
 msgstr "BECAUSE BLOG POSTS NEED METADATA!"

t/fmt/txt-markdown/YamlFrontMatter_KeysPaths.pot

@@ -35,27 +35,27 @@ msgid "I mean: why not?"
 msgstr ""
 
 #. type: Title #
-#: YamlFrontMatter_KeysPaths.md:28
+#: YamlFrontMatter_KeysPaths.md:29
 #, markdown-text, no-wrap
 msgid "YAML: does it fit in Markdown?"
 msgstr ""
 
 #. type: Plain text
-#: YamlFrontMatter_KeysPaths.md:32
+#: YamlFrontMatter_KeysPaths.md:33
 #, markdown-text
 msgid ""
 "Lots of Static Site Generators like Jekyll, Hugo, Lektor and more use a "
 "standard format: Markdown with YAML Front Matter."
 msgstr ""
 
 #. type: Plain text
-#: YamlFrontMatter_KeysPaths.md:34
+#: YamlFrontMatter_KeysPaths.md:35
 #, markdown-text
 msgid "Why"
 msgstr ""
 
 #. type: Plain text
-#: YamlFrontMatter_KeysPaths.md:37
+#: YamlFrontMatter_KeysPaths.md:38
 #, markdown-text
 msgid "Because blog posts need metadata!"
 msgstr ""

t/fmt/txt-markdown/YamlFrontMatter_KeysPaths.trans

@@ -1,5 +1,6 @@
 ---
 author: test
+emptytag:
 numeric_ignored_value: 22
 paragraph: "SOME TEXT TO TRANSLATE, PLEASE.\n"
 people: