feat: report unusual 'epub' namespace (usage) (#1624)

rdeltour · web-flow · commit cf16167443a4 · 2025-08-31T22:10:46.000+02:00
Report a USAGE message when a namespace other than the usual `http://www.idpf.org/2007/ops` URL is associated to the `epub` prefix in XHTML content documents. This is reported as HTM_010 (thereby repurposing this unused message ID). This is only reported as a USAGE, since the spec does not strictly requires that the `epub` prefix is tied to the well-known URL. But it can help catch typos as reported in #1601. Fixes #1601
diff --git a/src/main/java/com/adobe/epubcheck/ops/OPSHandler30.java b/src/main/java/com/adobe/epubcheck/ops/OPSHandler30.java
@@ -20,6 +20,7 @@
 import org.w3c.epubcheck.util.microsyntax.ViewportMeta;
 import org.w3c.epubcheck.util.microsyntax.ViewportMeta.ParseError;
 import org.w3c.epubcheck.util.url.URLUtils;
+import org.xml.sax.SAXException;
 
 import com.adobe.epubcheck.api.EPUBLocation;
 import com.adobe.epubcheck.api.EPUBProfile;
@@ -49,6 +50,7 @@
 import com.adobe.epubcheck.vocab.UncheckedVocab;
 import com.adobe.epubcheck.vocab.Vocab;
 import com.adobe.epubcheck.vocab.VocabUtil;
+import com.adobe.epubcheck.xml.Namespaces;
 import com.adobe.epubcheck.xml.model.XMLAttribute;
 import com.adobe.epubcheck.xml.model.XMLElement;
 import com.google.common.base.Joiner;
@@ -1106,4 +1108,14 @@ protected void checkLink()
     }
   }
 
+  @Override
+  public void startPrefixMapping(String prefix, String uri)
+    throws SAXException
+  {
+    super.startPrefixMapping(prefix, uri);
+    if ("epub".equals(prefix) && !(Namespaces.OPS.equals(uri))) {
+      report.message(MessageId.HTM_010, location(), uri);
+    }
+  }
+
 }
diff --git a/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties b/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties
@@ -45,7 +45,7 @@ HTM_004=Irregular DOCTYPE: found "%1$s", expected "%2$s".
 HTM_005=An external reference was found.
 HTM_007=Empty or whitespace-only value of attribute ssml:ph.
 HTM_009=The DOCTYPE provided is obsolete or irregular and can be removed.
-HTM_010=Namespace uri "%1$s" was found.
+HTM_010=Namespace "%1$s" is unusual for the prefix "epub".
 HTM_011=Entity is undeclared.
 HTM_011_SUG=Define the entity or use the numbered entity instead.
 HTM_025=Non-registered URI scheme type found in href.
diff --git a/src/test/resources/epub3/06-content-document/content-document-xhtml.feature b/src/test/resources/epub3/06-content-document/content-document-xhtml.feature
@@ -1010,3 +1010,11 @@ Feature: EPUB 3 — Content Documents — XHTML
     And the message contains 'rp'
     And no other errors or warnings are reported
 
+  #### Other
+
+  Scenario: Report an unrecognized `epub` namespace (informative)
+    Given the reporting level is set to usage
+    When checking document 'ns-epub-unknown-info.xhtml'
+    Then usage HTM-010 is reported
+    And the message contains 'Namespace "http://http://www.idpf.org/2007/ops" is unusual'
+    And no errors or warnings are reported
diff --git a/src/test/resources/epub3/06-content-document/files/ns-epub-unknown-info.xhtml b/src/test/resources/epub3/06-content-document/files/ns-epub-unknown-info.xhtml
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://http://www.idpf.org/2007/ops"
+	xml:lang="en" lang="en">
+	<head>
+		<meta charset="utf-8" />
+		<title>Test</title>
+	</head>
+	<body>
+		<h1>Test</h1>
+	</body>
+</html>
