fixes nav doc validation to be more faithful to the spec:

- only restrict a nav element's content model when it carries an epub:type attribute
- require a first-child heading for all nav elements not defined in the spec (including without an epub:type)
- require at least one li child for ol (also fixes existing errors in test docs)
- add warning that nav elements should have an epub:type attribute

src/main/resources/com/adobe/epubcheck/schema/30/epub-nav-30.rnc

@@ -1,10 +1,21 @@
-
-
+
    default namespace = "http://www.w3.org/1999/xhtml"
    namespace epub = "http://www.idpf.org/2007/ops"
-      
+
    include "epub-xhtml-30.rnc" {   
-        html5.nav.content = html5.headings.class?, html5.ol     
-        html5.oli.content = html5.a.phrasing | ((html5.a.phrasing | html5.span), html5.ol)
+        html5.nav.attlist &= epub.nav.attrs
    }
-
+
+   epub.nav.attrs &= html5.global.common.attrs & epub.nav.xml.attrs
+   epub.nav.xml.attrs &= html5.xml.lang.attr? & html5.xml.base.attr? & html5.xml.space.attr?   
+
+   html5.sections.class |= epub.nav
+
+   epub.nav = element nav { epub.type.attr & epub.nav.attrs & epub.nav.content }
+   epub.nav.content = html5.headings.class?, epub.nav.ol     
+
+   epub.nav.ol = element ol { html5.ol.attlist & epub.nav.ol.content }
+   epub.nav.ol.content = epub.nav.oli+
+
+   epub.nav.oli = element li { html5.oli.attlist & epub.nav.oli.content }
+   epub.nav.oli.content = html5.a.phrasing | ((html5.a.phrasing | html5.span), epub.nav.ol)

src/main/resources/com/adobe/epubcheck/schema/30/epub-nav-30.sch

@@ -16,7 +16,7 @@
     </pattern>
 
     <pattern id="span-no-sublist">
-        <rule context="html:body//html:nav//html:span">
+        <rule context="html:body//html:nav[@epub:type]//html:span">
             <assert test="count(.//ol) = 0"> The span element must only be used as heading for flat
                 sublists (not hierarchical navigation structures) </assert>
         </rule>
@@ -30,15 +30,15 @@
     </pattern>
 
     <pattern id="link-labels">
-        <rule context="html:nav//html:ol//html:a">
+        <rule context="html:nav[@epub:type]//html:ol//html:a">
             <assert
                 test="string-length(normalize-space(concat(.,./html:img/@alt,.//@aria-label))) > 0"
                 >Anchors within nav elements must contain text</assert>
         </rule>
     </pattern>
 
     <pattern id="span-labels">
-        <rule context="html:nav//html:ol//html:span">
+        <rule context="html:nav[@epub:type]//html:ol//html:span">
             <assert
                 test="string-length(normalize-space(concat(.,./html:img/@alt,.//@aria-label))) > 0"
                 >Spans within nav elements must contain text</assert>
@@ -48,21 +48,25 @@
     <pattern id="req-heading">
         <rule
             context="html:nav[not(tokenize(@epub:type,'\s+') = ('toc','page-list','landmarks'))]">
-            <let name="fc" value="local-name(./*[1])"/>
-            <assert test="(starts-with($fc,'h') and string-length($fc) = 2) or ($fc = 'hgroup')">nav
-                elements other than 'toc', 'page-list' and 'landmarks' must contain a heading as the
+            <assert test="child::*[1][self::html:h1|self::html:h2|self::html:h3|self::html:h4|self::html:h5|self::html:h6]">nav
+                elements other than 'toc', 'page-list' and 'landmarks' must have a heading as their
                 first child</assert>
         </rule>
     </pattern>
 
     <pattern id="heading-content">
-        <rule context="html:h1|html:h2|html:h3|html:h4|html:h5|html:h6|html:hgroup">
+        <rule context="html:h1|html:h2|html:h3|html:h4|html:h5|html:h6">
             <assert
                 test="string-length(normalize-space(concat(.,./html:img/@alt,.//@aria-label))) > 0"
                 >Heading elements must contain text</assert>
         </rule>
     </pattern>
-
+
+    <pattern id="other-nav-type">
+        <rule context="html:nav">
+            <report test="not(@epub:type)">WARNING: nav elements should have an epub:type attribute</report>
+        </rule>
+    </pattern>
 
     <!-- warnings mode <pattern id="page-list-flat">
         <rule context="html:body//html:nav[@epub:type='page-list']">

src/test/java/com/adobe/epubcheck/nav/NavCheckerTest.java

@@ -117,6 +117,7 @@ public void testValidateDocumentValidNav001()
   public void testValidateDocumentNoTocNav()
   {
     Collections.addAll(expectedErrors, MessageId.RSC_005, MessageId.RSC_005, MessageId.RSC_005);
+    Collections.addAll(expectedWarnings, MessageId.RSC_017);
     testValidateDocument("invalid/noTocNav.xhtml");
   }
 
@@ -183,6 +184,7 @@ public void testValidateDocumentNavNoToc()
   public void testValidateDocumentNavReqHeading()
   {
     Collections.addAll(expectedErrors, MessageId.RSC_005);
+    Collections.addAll(expectedWarnings, MessageId.RSC_017);
     testValidateDocument("invalid/req-heading.xhtml");
   }
 

src/test/resources/com/adobe/epubcheck/test/toc/missing_epub_type_expected_results.json

@@ -8,7 +8,7 @@
     "elapsedTime" : 85,
     "nFatal" : 0,
     "nError" : 1,
-    "nWarning" : 0,
+    "nWarning" : 1,
     "nUsage" : 4
   },
   "publication" : {
@@ -237,5 +237,17 @@
       "context" : null
     } ],
     "suggestion" : null
+  }, {
+    "ID" : "RSC-017",
+    "severity" : "WARNING",
+    "message" : "Warning while parsing file: nav elements should have an epub:type attribute",
+    "additionalLocations" : 0,
+    "locations" : [ {
+      "path" : "OPS/toc.xhtml",
+      "line" : 9,
+      "column" : 6,
+      "context" : null
+    } ],
+    "suggestion" : null
   } ]
 }