LUCENE-9454: Remove version field on Analyzer (#154)

Version switching on Analyzer behaviour should be implemented
in the various component factories, rather than on a mutable
setting on Analyzer itself.

lucene/CHANGES.txt

@@ -119,6 +119,8 @@ API Changes
 * LUCENE-9204: SpanQuery and its subclasses have been moved from core/ into the
   queries/ module. (Alan Woodward)
 
+* LUCENE-9454: Analyzer no longer has a mutable version field. (Alan Woodward)
+
 Improvements
 
 * LUCENE-9960: Avoid unnecessary top element replacement for equal elements in PriorityQueue. (Dawid Weiss)

lucene/analysis/common/src/java/org/apache/lucene/analysis/custom/CustomAnalyzer.java

@@ -129,7 +129,6 @@ public final class CustomAnalyzer extends Analyzer {
   private final Integer posIncGap, offsetGap;
 
   CustomAnalyzer(
-      Version defaultMatchVersion,
       CharFilterFactory[] charFilters,
       TokenizerFactory tokenizer,
       TokenFilterFactory[] tokenFilters,
@@ -140,9 +139,6 @@ public final class CustomAnalyzer extends Analyzer {
     this.tokenFilters = tokenFilters;
     this.posIncGap = posIncGap;
     this.offsetGap = offsetGap;
-    if (defaultMatchVersion != null) {
-      setVersion(defaultMatchVersion);
-    }
   }
 
   @Override
@@ -590,7 +586,6 @@ public final class CustomAnalyzer extends Analyzer {
         throw new IllegalStateException("You have to set at least a tokenizer.");
       }
       return new CustomAnalyzer(
-          defaultMatchVersion.get(),
           charFilters.toArray(new CharFilterFactory[charFilters.size()]),
           tokenizer.get(),
           tokenFilters.toArray(new TokenFilterFactory[tokenFilters.size()]),

lucene/analysis/common/src/test/org/apache/lucene/analysis/custom/TestCustomAnalyzer.java

@@ -26,6 +26,7 @@ import java.util.Map;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.CharFilter;
 import org.apache.lucene.analysis.CharFilterFactory;
+import org.apache.lucene.analysis.LowerCaseFilter;
 import org.apache.lucene.analysis.TokenFilterFactory;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
@@ -69,7 +70,6 @@ public class TestCustomAnalyzer extends BaseTokenStreamTestCase {
     assertSame(LowerCaseFilterFactory.class, tokenFilters.get(1).getClass());
     assertEquals(0, a.getPositionIncrementGap("dummy"));
     assertEquals(1, a.getOffsetGap("dummy"));
-    assertSame(Version.LATEST, a.getVersion());
 
     assertAnalyzesTo(
         a, "foo bar FOO BAR", new String[] {"foo", "bar", "foo", "bar"}, new int[] {1, 1, 1, 1});
@@ -97,7 +97,6 @@ public class TestCustomAnalyzer extends BaseTokenStreamTestCase {
     assertSame(LowerCaseFilterFactory.class, tokenFilters.get(1).getClass());
     assertEquals(0, a.getPositionIncrementGap("dummy"));
     assertEquals(1, a.getOffsetGap("dummy"));
-    assertSame(Version.LATEST, a.getVersion());
 
     assertAnalyzesTo(
         a, "foo bar FOO BAR", new String[] {"foo", "bar", "foo", "bar"}, new int[] {1, 1, 1, 1});
@@ -109,6 +108,23 @@ public class TestCustomAnalyzer extends BaseTokenStreamTestCase {
     a.close();
   }
 
+  public void testVersionAwareFilter() throws Exception {
+    CustomAnalyzer a =
+        CustomAnalyzer.builder()
+            .withDefaultMatchVersion(Version.LUCENE_8_0_0)
+            .withTokenizer(StandardTokenizerFactory.class)
+            .addTokenFilter(DummyVersionAwareTokenFilterFactory.class)
+            .build();
+    assertAnalyzesTo(a, "HELLO WORLD", new String[] {"HELLO", "WORLD"});
+
+    CustomAnalyzer b =
+        CustomAnalyzer.builder()
+            .withTokenizer(StandardTokenizerFactory.class)
+            .addTokenFilter(DummyVersionAwareTokenFilterFactory.class)
+            .build();
+    assertAnalyzesTo(b, "HELLO WORLD", new String[] {"hello", "world"});
+  }
+
   public void testFactoryHtmlStripClassicFolding() throws Exception {
     CustomAnalyzer a =
         CustomAnalyzer.builder()
@@ -131,7 +147,6 @@ public class TestCustomAnalyzer extends BaseTokenStreamTestCase {
     assertSame(LowerCaseFilterFactory.class, tokenFilters.get(1).getClass());
     assertEquals(100, a.getPositionIncrementGap("dummy"));
     assertEquals(1000, a.getOffsetGap("dummy"));
-    assertSame(LUCENE_8_0_0, a.getVersion());
 
     assertAnalyzesTo(
         a,
@@ -168,7 +183,6 @@ public class TestCustomAnalyzer extends BaseTokenStreamTestCase {
     assertSame(LowerCaseFilterFactory.class, tokenFilters.get(1).getClass());
     assertEquals(100, a.getPositionIncrementGap("dummy"));
     assertEquals(1000, a.getOffsetGap("dummy"));
-    assertSame(LUCENE_8_0_0, a.getVersion());
 
     assertAnalyzesTo(
         a,
@@ -204,7 +218,6 @@ public class TestCustomAnalyzer extends BaseTokenStreamTestCase {
     assertSame(StopFilterFactory.class, tokenFilters.get(0).getClass());
     assertEquals(0, a.getPositionIncrementGap("dummy"));
     assertEquals(1, a.getOffsetGap("dummy"));
-    assertSame(Version.LATEST, a.getVersion());
 
     assertAnalyzesTo(a, "foo Foo Bar", new String[0]);
     a.close();
@@ -486,6 +499,21 @@ public class TestCustomAnalyzer extends BaseTokenStreamTestCase {
     }
   }
 
+  public static class DummyVersionAwareTokenFilterFactory extends TokenFilterFactory {
+
+    public DummyVersionAwareTokenFilterFactory(Map<String, String> args) {
+      super(args);
+    }
+
+    @Override
+    public TokenStream create(TokenStream input) {
+      if (luceneMatchVersion.equals(Version.LUCENE_8_0_0)) {
+        return input;
+      }
+      return new LowerCaseFilter(input);
+    }
+  }
+
   public void testNormalization() throws IOException {
     CustomAnalyzer analyzer1 =
         CustomAnalyzer.builder()

lucene/core/src/java/org/apache/lucene/analysis/Analyzer.java

@@ -30,7 +30,6 @@ import org.apache.lucene.store.AlreadyClosedException;
 import org.apache.lucene.util.AttributeFactory;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.CloseableThreadLocal;
-import org.apache.lucene.util.Version;
 
 /**
  * An Analyzer builds TokenStreams, which analyze text. It thus represents a policy for extracting
@@ -86,7 +85,6 @@ import org.apache.lucene.util.Version;
 public abstract class Analyzer implements Closeable {
 
   private final ReuseStrategy reuseStrategy;
-  private Version version = Version.LATEST;
 
   // non final as it gets nulled if closed; pkg private for access by ReuseStrategy's final helper
   // methods:
@@ -329,16 +327,6 @@ public abstract class Analyzer implements Closeable {
     return reuseStrategy;
   }
 
-  /** Set the version of Lucene this analyzer should mimic the behavior for for analysis. */
-  public void setVersion(Version v) {
-    version = v; // TODO: make write once?
-  }
-
-  /** Return the version of Lucene this analyzer will mimic the behavior of for analysis. */
-  public Version getVersion() {
-    return version;
-  }
-
   /** Frees persistent resources used by this Analyzer */
   @Override
   public void close() {