hunspell: allow ignoring exceptions on duplicate ICONV/OCONV mappings (#13155)

hunspell: allow ignoring exceptions on duplicate ICONV/OCONV mappings

lucene/CHANGES.txt

@@ -202,6 +202,8 @@ Improvements
 * GITHUB#13087: Changed `static final Set` constants to be immutable. Among others it affected
   ScandinavianNormalizer.ALL_FOLDINGS set with public access. (Dmitry Cherniachenko)
 
+* GITHUB#13155: Hunspell: allow ignoring exceptions on duplicate ICONV/OCONV mappings (Peter Gromov)
+
 Optimizations
 ---------------------
 

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

@@ -815,7 +815,7 @@ public class Dictionary {
 
     for (int i = 0; i < num; i++) {
       String[] parts = splitBySpace(reader, reader.readLine(), 3);
-      if (mappings.put(parts[1], parts[2]) != null) {
+      if (mappings.put(parts[1], parts[2]) != null && !tolerateDuplicateConversionMappings()) {
         throw new IllegalStateException("duplicate mapping specified for: " + parts[1]);
       }
     }
@@ -1167,6 +1167,14 @@ public class Dictionary {
     return false;
   }
 
+  /**
+   * Whether duplicate ICONV/OCONV lines should be silently ignored. False by default: an {@link
+   * IllegalStateException} will happen.
+   */
+  protected boolean tolerateDuplicateConversionMappings() {
+    return false;
+  }
+
   char[] allNonSuggestibleFlags() {
     return Dictionary.toSortedCharArray(
         Stream.of(HIDDEN_FLAG, noSuggest, forbiddenword, onlyincompound, subStandard)

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

@@ -206,6 +206,11 @@ public class TestDictionary extends LuceneTestCase {
         protected boolean tolerateAffixRuleCountMismatches() {
           return true;
         }
+
+        @Override
+        protected boolean tolerateDuplicateConversionMappings() {
+          return true;
+        }
       };
     }
   }

lucene/analysis/common/src/test/org/apache/lucene/analysis/hunspell/forgivable-errors.aff

@@ -13,3 +13,7 @@ MAP a b
 SFX A Y 1
 SFX A   nout        l          [aeiouyáéíóúýůěr][^aeiouyáéíóúýůěrl][^aeiouy
 SFX A b c d
+
+ICONV 2
+ICONV x y
+ICONV x y