LUCENE-9783: Hunspell: don't suggest more than 4 ngram corrections by default (#2388)

lucene/analysis/common/src/java/org/apache/lucene/analysis/hunspell/Dictionary.java

@@ -166,7 +166,7 @@ public class Dictionary {
   List<RepEntry> repTable = new ArrayList<>();
   List<List<String>> mapTable = new ArrayList<>();
   int maxDiff = 5;
-  int maxNGramSuggestions = Integer.MAX_VALUE;
+  int maxNGramSuggestions = 4;
   boolean onlyMaxDiff;
   char noSuggest, subStandard;
   ConvTable iconv, oconv;

lucene/analysis/common/src/java/org/apache/lucene/analysis/hunspell/GeneratingSuggester.java

@@ -298,7 +298,7 @@ class GeneratingSuggester {
           && result.stream().noneMatch(weighted.word::contains)
           && speller.checkWord(weighted.word)) {
         result.add(weighted.word);
-        if (result.size() > dictionary.maxNGramSuggestions) {
+        if (result.size() >= dictionary.maxNGramSuggestions) {
           break;
         }
       }

lucene/analysis/common/src/test/org/apache/lucene/analysis/hunspell/TestSpellChecking.java

@@ -200,6 +200,10 @@ public class TestSpellChecking extends StemmerTestBase {
     doTest("sug2");
   }
 
+  public void testMaxNGramSugsDefaultIsNotUnlimited() throws Exception {
+    doTest("maxNGramSugsDefault");
+  }
+
   public void testMixedCaseSuggestionHeuristics() throws Exception {
     doTest("i58202");
   }

lucene/analysis/common/src/test/org/apache/lucene/analysis/hunspell/maxNGramSugsDefault.dic

@@ -0,0 +1,13 @@
+12
+cryptography
+cryptographer
+crystallographic
+cartographic
+photographic
+typographic
+cryptogram
+topographic
+orthographic
+tomographic
+phonographic
+pictograph

lucene/analysis/common/src/test/org/apache/lucene/analysis/hunspell/maxNGramSugsDefault.sug

@@ -0,0 +1 @@
+cryptography, cryptographer, crystallographic, cartographic

lucene/analysis/common/src/test/org/apache/lucene/analysis/hunspell/maxNGramSugsDefault.wrong

@@ -0,0 +1 @@
+cryptographic