fix (todo): correct doc.id of remote search result if no match with newly

calculated doc hash if different.
Testing showed that in some cases delivered url doesn't match the local
calculated hash. In this case replace doc.id (and host_id_s) with calculation
from url.

source/net/yacy/kelondro/data/meta/URIMetadataNode.java

@@ -171,9 +171,21 @@ public class URIMetadataNode extends SolrDocument /* implements Comparable<URIMe
         Float scorex = (Float) doc.getFieldValue("score"); // this is a special Solr field containing the ranking score of a search result
         this.score = scorex == null ? 0.0f : scorex.floatValue();
         */
-        final byte[] hash = ASCII.getBytes(getString(CollectionSchema.id)); // TODO: can we trust this id ?
+        final String hashstr = getString(CollectionSchema.id); // id or empty string
         final String urlRaw = getString(CollectionSchema.sku);
-        this.url = new DigestURL(urlRaw, hash);
+        this.url = new DigestURL(urlRaw);
+        if (!hashstr.isEmpty()) { // remote id might not correspond in all cases
+            final String myhash = ASCII.String(this.url.hash());
+            if (!hashstr.equals(myhash)) {
+                this.addField(CollectionSchema.id.getSolrFieldName(), myhash);
+                ConcurrentLog.fine("URIMetadataNode", "updated document.ID of " + urlRaw + " from " + hashstr + " to " + myhash);
+                // ususally the hosthash matches but just to be on the safe site
+                final String hostidstr = getString(CollectionSchema.host_id_s); // id or empty string
+                if (!hostidstr.isEmpty() && !hostidstr.equals(this.url.hosthash())) {
+                    this.addField(CollectionSchema.host_id_s.getSolrFieldName(), this.url.hosthash());
+                }
+            }
+        }
     }
 
     public URIMetadataNode(final SolrDocument doc, final WordReferenceVars searchedWord, final float scorex) throws MalformedURLException {
@@ -377,7 +389,6 @@ public class URIMetadataNode extends SolrDocument /* implements Comparable<URIMe
      */
     public String language() {
         String language = getString(CollectionSchema.language_s);
-        if (language == null || language.length() == 0) return "";
         return language;
     }