Warn about self-closing tag syntax if profile is “html-strict” (#73)

Author: sideshowbarker

src/nu/validator/htmlparser/impl/ErrorReportingTokenizer.java

@@ -710,6 +710,18 @@ private boolean isAstralPrivateUse(int c) {
         note("xhtml1", "Unquoted attribute value.");
     }
 
+    @Override
+    protected void noteSelfClosingTag() throws SAXException {
+        note("html-strict",
+                "Self-closing tag syntax in text/html documents is widely"
+                        + " discouraged; it’s unnecessary and interacts badly"
+                        + " with other HTML features (e.g., unquoted attribute"
+                        + " values). If you’re using a tool that injects"
+                        + " self-closing tag syntax into all void elements,"
+                        + " without any option to prevent it from doing so,"
+                        + " then consider switching to a different tool.");
+    }
+
     /**
      * Sets the transitionHandler.
      *

src/nu/validator/htmlparser/impl/Tokenizer.java

@@ -2292,6 +2292,7 @@ private void ensureBufferSpace(int inputLength) throws SAXException {
                              * flag of the current tag token. Emit the current
                              * tag token.
                              */
+                            noteSelfClosingTag();
                             state = transition(state, emitCurrentTagToken(true, pos), reconsume, pos);
                             if (shouldSuspend) {
                                 break stateloop;
@@ -7587,6 +7588,9 @@ protected void noteAttributeWithoutValue() throws SAXException {
     protected void noteUnquotedAttributeValue() throws SAXException {
     }
 
+    protected void noteSelfClosingTag() throws SAXException {
+    }
+
     /**
      * Sets the encodingDeclarationHandler.
      *