Fix searching for Non-ASCII characters

src/main/java/org/jabref/logic/search/indexing/BibFieldsIndexer.java

@@ -5,7 +5,9 @@
 import java.util.Map;
 
 import org.jabref.gui.util.BackgroundTask;
+import org.jabref.logic.cleanup.Formatter;
 import org.jabref.logic.l10n.Localization;
+import org.jabref.logic.layout.format.LatexToUnicodeFormatter;
 import org.jabref.logic.util.HeadlessExecutorService;
 import org.jabref.model.database.BibDatabaseContext;
 import org.jabref.model.entry.BibEntry;
@@ -27,6 +29,7 @@
 
 public class BibFieldsIndexer implements LuceneIndexer {
     private static final Logger LOGGER = LoggerFactory.getLogger(BibFieldsIndexer.class);
+    private static final Formatter FORMATTER = new LatexToUnicodeFormatter();
     private final BibDatabaseContext databaseContext;
     private final String libraryName;
     private final Directory indexDirectory;
@@ -82,8 +85,9 @@ private void addToIndex(BibEntry bibEntry) {
 
             StringBuilder allFields = new StringBuilder(bibEntry.getType().getName());
             for (Map.Entry<Field, String> mapEntry : bibEntry.getFieldMap().entrySet()) {
-                document.add(new TextField(mapEntry.getKey().getName(), mapEntry.getValue(), storeDisabled));
-                allFields.append('\n').append(mapEntry.getValue());
+                String value = FORMATTER.format(mapEntry.getValue());
+                document.add(new TextField(mapEntry.getKey().getName(), value, storeDisabled));
+                allFields.append('\n').append(value);
             }
             document.add(new TextField(SearchFieldConstants.DEFAULT_FIELD.toString(), allFields.toString(), storeDisabled));
             indexWriter.addDocument(document);

src/main/java/org/jabref/model/search/SearchQuery.java

@@ -12,16 +12,17 @@
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
+import org.jabref.logic.cleanup.Formatter;
+import org.jabref.logic.layout.format.LatexToUnicodeFormatter;
+
 import org.apache.lucene.queryparser.classic.MultiFieldQueryParser;
 import org.apache.lucene.queryparser.classic.ParseException;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.highlight.QueryTermExtractor;
 import org.apache.lucene.search.highlight.WeightedTerm;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 public class SearchQuery {
-
+    private static final Formatter FORMATTER = new LatexToUnicodeFormatter();
     /**
      * The mode of escaping special characters in regular expressions
      */
@@ -59,7 +60,6 @@ String format(String regex) {
         abstract String format(String regex);
     }
 
-    private final static Logger LOGGER = LoggerFactory.getLogger(SearchQuery.class);
     protected final String query;
     protected Query parsedQuery;
     protected String parseError;
@@ -87,7 +87,7 @@ public SearchQuery(String query, EnumSet<SearchFlags> searchFlags) {
         queryParser.setAllowLeadingWildcard(true);
 
         try {
-            parsedQuery = queryParser.parse(query);
+            parsedQuery = queryParser.parse(FORMATTER.format(query));
             parseError = null;
         } catch (ParseException e) {
             parsedQuery = null;

src/test/java/org/jabref/logic/search/LuceneQueryParserTest.java

@@ -0,0 +1,38 @@
+package org.jabref.logic.search;
+
+import java.util.EnumSet;
+import java.util.stream.Stream;
+
+import org.jabref.model.search.SearchFlags;
+import org.jabref.model.search.SearchQuery;
+
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class LuceneQueryParserTest {
+
+    public static Stream<Arguments> searchQuires() {
+        return Stream.of(
+                // unicode
+                Arguments.of("preissinger", "preißinger"),
+                Arguments.of("jesus", "jesús"),
+                Arguments.of("breitenbucher", "breitenbücher"),
+
+                // latex
+                Arguments.of("preissinger", "prei{\\ss}inger"),
+                Arguments.of("jesus", "jes{\\'{u}}s"),
+                Arguments.of("breitenbucher", "breitenb{\\\"{u}}cher")
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource
+    void searchQuires(String expected, String query) {
+        expected = "(all:" + expected + ")^4.0";
+        SearchQuery searchQuery = new SearchQuery(query, EnumSet.noneOf(SearchFlags.class));
+        assertEquals(expected, searchQuery.getParsedQuery().toString());
+    }
+}