Script: fields API for x-pack version, doc version, seq no, mumur3 (#81476)

Adds scripting fields API support the rest of the long fields:
* [`_version`](https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-index_.html#index-versioning) - `VersionDocValuesField`
* [`_seq_no`](https://www.elastic.co/guide/en/elasticsearch/reference/master/optimistic-concurrency-control.html) - `SeqNoDocValuesField`
* [`murmur3`](https://www.elastic.co/guide/en/elasticsearch/plugins/current/mapper-murmur3-usage.html) - `Murmur3DocValueField`
  * Added Painless support to the murmur3 mapper plugin.

All `SortedNumericDocValues` that are interpreted as longs are now subclasses of `AbstractLongDocValuesField`, including murmur, doc version and seq no above as well as `LongDocValuesField` and `UnsignedLongDocValuesField`

Also adds:
* [x-pack's version](https://www.elastic.co/guide/en/elasticsearch/reference/master/version.html) - `VersionStringDocValuesField`
  * Created new `Version` value type as a location for future helpers for comparing versions. 
    * Implements `toString` for the expected representation of the version
  * Implements `asString(String)` and `asString(int, String)`, `asStrings()` converters on field.


Refs: #79105

docs/changelog/81476.yaml

@@ -0,0 +1,5 @@
+pr: 81476
+summary: "Script: fields API for x-pack version, doc version, seq no, mumur3"
+area: Infra/Scripting
+type: enhancement
+issues: []

modules/lang-painless/src/main/resources/org/elasticsearch/painless/org.elasticsearch.script.fields.txt

@@ -100,3 +100,16 @@ class org.elasticsearch.script.field.IpDocValuesField @dynamic_type {
   String asString(String)
   String asString(int, String)
 }
+
+class org.elasticsearch.script.field.AbstractLongDocValuesField @dynamic_type {
+  long get(long)
+  long get(int, long)
+}
+
+# subclass of AbstractLongDocValuesField
+class org.elasticsearch.script.field.SeqNoDocValuesField @dynamic_type {
+}
+
+# subclass of AbstractLongDocValuesField
+class org.elasticsearch.script.field.VersionDocValuesField @dynamic_type {
+}

modules/lang-painless/src/yamlRestTest/resources/rest-api-spec/test/painless/50_script_doc_values.yml

@@ -1446,3 +1446,81 @@ setup:
               script:
                 source: "int value = field('dne').get(1, 1); value"
   - match: { hits.hits.0.fields.field.0: 1 }
+
+---
+"version and sequence number":
+  - do:
+      indices.create:
+        index: versiontest
+        body:
+          settings:
+            number_of_shards: 1
+          mappings:
+            properties:
+              keyword:
+                type: keyword
+
+  - do:
+      index:
+        index: test
+        id: 3000
+        version: 50
+        version_type: external
+        body:
+          keyword: "3k"
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query: { term: { _id: 3000 } }
+          script_fields:
+            ver:
+              script:
+                source: "field('_version').get(10000)"
+            seq:
+              script:
+                source: "field('_seq_no').get(10000)"
+  - match: { hits.hits.0.fields.ver.0: 50 }
+  - match: { hits.hits.0.fields.seq.0: 3 }
+
+  - do:
+      index:
+        index: test
+        id: 3000
+        version: 60
+        version_type: external
+        body:
+          keyword: "3k+1"
+  - do:
+      indices.refresh: {}
+
+  - do:
+      catch:      conflict
+      index:
+        index: test
+        id: 3000
+        version: 55
+        version_type: external
+        body:
+          keyword: "3k+2"
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        rest_total_hits_as_int: true
+        body:
+          query: { term: { _id: 3000 } }
+          script_fields:
+            ver:
+              script:
+                source: "field('_version').get(10000)"
+            seq:
+              script:
+                source: "field('_seq_no').get(10000)"
+  - match: { hits.hits.0.fields.ver.0: 60 }
+  - match: { hits.hits.0.fields.seq.0: 4 }

plugins/mapper-murmur3/build.gradle

@@ -11,6 +11,12 @@ apply plugin: 'elasticsearch.yaml-rest-compat-test'
 esplugin {
   description 'The Mapper Murmur3 plugin allows to compute hashes of a field\'s values at index-time and to store them in the index.'
   classname 'org.elasticsearch.plugin.mapper.MapperMurmur3Plugin'
+  extendedPlugins = ['lang-painless']
+}
+
+dependencies {
+  compileOnly project(':modules:lang-painless:spi')
+  testImplementation project(':modules:lang-painless')
 }
 
 restResources {
@@ -18,3 +24,8 @@ restResources {
     include '_common', 'indices', 'index', 'search'
   }
 }
+
+testClusters.configureEach {
+  testDistribution = 'DEFAULT'
+  setting 'xpack.security.enabled', 'false'
+}

plugins/mapper-murmur3/src/main/java/org/elasticsearch/index/mapper/murmur3/Murmur3FieldMapper.java

@@ -12,14 +12,11 @@ import org.apache.lucene.document.FieldType;
 import org.apache.lucene.document.SortedNumericDocValuesField;
 import org.apache.lucene.document.StoredField;
 import org.apache.lucene.index.IndexOptions;
-import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.hash.MurmurHash3;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.IndexNumericFieldData.NumericType;
-import org.elasticsearch.index.fielddata.ScriptDocValues.Longs;
-import org.elasticsearch.index.fielddata.ScriptDocValues.LongsSupplier;
 import org.elasticsearch.index.fielddata.plain.SortedNumericIndexFieldData;
 import org.elasticsearch.index.mapper.DocumentParserContext;
 import org.elasticsearch.index.mapper.FieldMapper;
@@ -29,8 +26,7 @@ import org.elasticsearch.index.mapper.SourceValueFetcher;
 import org.elasticsearch.index.mapper.TextSearchInfo;
 import org.elasticsearch.index.mapper.ValueFetcher;
 import org.elasticsearch.index.query.SearchExecutionContext;
-import org.elasticsearch.script.field.DelegateDocValuesField;
-import org.elasticsearch.script.field.ToScriptField;
+import org.elasticsearch.script.field.murmur3.Murmur3DocValueField;
 import org.elasticsearch.search.lookup.SearchLookup;
 
 import java.io.IOException;
@@ -84,11 +80,6 @@ public class Murmur3FieldMapper extends FieldMapper {
     // this only exists so a check can be done to match the field type to using murmur3 hashing...
     public static class Murmur3FieldType extends MappedFieldType {
 
-        public static final ToScriptField<SortedNumericDocValues> TO_SCRIPT_FIELD = (dv, n) -> new DelegateDocValuesField(
-            new Longs(new LongsSupplier(dv)),
-            n
-        );
-
         private Murmur3FieldType(String name, boolean isStored, Map<String, String> meta) {
             super(name, false, isStored, true, TextSearchInfo.NONE, meta);
         }
@@ -101,7 +92,7 @@ public class Murmur3FieldMapper extends FieldMapper {
         @Override
         public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, Supplier<SearchLookup> searchLookup) {
             failIfNoDocValues();
-            return new SortedNumericIndexFieldData.Builder(name(), NumericType.LONG, TO_SCRIPT_FIELD);
+            return new SortedNumericIndexFieldData.Builder(name(), NumericType.LONG, Murmur3DocValueField::new);
         }
 
         @Override

plugins/mapper-murmur3/src/main/java/org/elasticsearch/script/field/murmur3/Murmur3DocValueField.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.script.field.murmur3;
+
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.elasticsearch.script.field.AbstractLongDocValuesField;
+
+public class Murmur3DocValueField extends AbstractLongDocValuesField {
+
+    public Murmur3DocValueField(SortedNumericDocValues input, String name) {
+        super(input, name);
+    }
+}

plugins/mapper-murmur3/src/main/java/org/elasticsearch/script/field/murmur3/Murmur3PainlessExtension.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.script.field.murmur3;
+
+import org.elasticsearch.painless.spi.PainlessExtension;
+import org.elasticsearch.painless.spi.Whitelist;
+import org.elasticsearch.painless.spi.WhitelistLoader;
+import org.elasticsearch.script.ScriptContext;
+
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static java.util.Collections.singletonList;
+import static org.elasticsearch.script.ScriptModule.CORE_CONTEXTS;
+
+public class Murmur3PainlessExtension implements PainlessExtension {
+
+    private static final Whitelist WHITELIST = WhitelistLoader.loadFromResourceFiles(
+        Murmur3PainlessExtension.class,
+        "org.elasticsearch.field.murmur3.txt"
+    );
+
+    @Override
+    public Map<ScriptContext<?>, List<Whitelist>> getContextWhitelists() {
+        List<Whitelist> whitelist = singletonList(WHITELIST);
+        Map<ScriptContext<?>, List<Whitelist>> contextWhitelists = new HashMap<>(CORE_CONTEXTS.size());
+        for (ScriptContext<?> scriptContext : CORE_CONTEXTS.values()) {
+            contextWhitelists.put(scriptContext, whitelist);
+        }
+        return contextWhitelists;
+    }
+}

plugins/mapper-murmur3/src/main/resources/META-INF/services/org.elasticsearch.painless.spi.PainlessExtension

@@ -0,0 +1 @@
+org.elasticsearch.script.field.murmur3.Murmur3PainlessExtension

plugins/mapper-murmur3/src/main/resources/org/elasticsearch/script/field/murmur3/org.elasticsearch.field.murmur3.txt

@@ -0,0 +1,11 @@
+#
+# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+# or more contributor license agreements. Licensed under the Elastic License
+# 2.0 and the Server Side Public License, v 1; you may not use this file except
+# in compliance with, at your election, the Elastic License 2.0 or the Server
+# Side Public License, v 1.
+#
+
+# subclass of AbstractLongDocValuesField
+class org.elasticsearch.script.field.murmur3.Murmur3DocValueField @dynamic_type {
+}

plugins/mapper-murmur3/src/yamlRestTest/resources/rest-api-spec/test/mapper_murmur3/10_basic.yml

@@ -1,9 +1,7 @@
 # Integration tests for Mapper Murmur3 components
 #
 
----
-"Mapper Murmur3":
-
+setup:
     - do:
         indices.create:
             index: test
@@ -20,6 +18,8 @@
     - do:
         indices.refresh: {}
 
+---
+"Mapper Murmur3":
     - do:
         search:
             rest_total_hits_as_int: true
@@ -60,3 +60,27 @@
             body: { "aggs": { "foo_count": { "cardinality": { "field": "foo.hash" } } } }
 
     - match: { aggregations.foo_count.value: 3 }
+
+---
+"Mumur3 script fields api":
+
+  - do:
+      index:
+        index: test
+        id: 1
+        body: { "foo": "foo" }
+
+  - do:
+      indices.refresh: {}
+
+  - do:
+      search:
+        index: test
+        body:
+          sort: [ { foo.hash: desc } ]
+          script_fields:
+            field:
+              script:
+                source: "field('foo.hash').get(10L)"
+
+  - match: { hits.hits.0.fields.field.0: -2129773440516405919 }

server/src/main/java/org/elasticsearch/index/fielddata/ScriptDocValues.java

@@ -8,7 +8,6 @@
 
 package org.elasticsearch.index.fielddata;
 
-import org.apache.lucene.index.SortedNumericDocValues;
 import org.apache.lucene.util.ArrayUtil;
 import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.BytesRefBuilder;
@@ -94,48 +93,6 @@ public abstract class ScriptDocValues<T> extends AbstractList<T> {
         }
     }
 
-    public static class LongsSupplier implements Supplier<Long> {
-
-        private final SortedNumericDocValues in;
-        private long[] values = new long[0];
-        private int count;
-
-        public LongsSupplier(SortedNumericDocValues in) {
-            this.in = in;
-        }
-
-        @Override
-        public void setNextDocId(int docId) throws IOException {
-            if (in.advanceExact(docId)) {
-                resize(in.docValueCount());
-                for (int i = 0; i < count; i++) {
-                    values[i] = in.nextValue();
-                }
-            } else {
-                resize(0);
-            }
-        }
-
-        /**
-         * Set the {@link #size()} and ensure that the {@link #values} array can
-         * store at least that many entries.
-         */
-        private void resize(int newSize) {
-            count = newSize;
-            values = ArrayUtil.grow(values, count);
-        }
-
-        @Override
-        public Long getInternal(int index) {
-            return values[index];
-        }
-
-        @Override
-        public int size() {
-            return count;
-        }
-    }
-
     public static class Longs extends ScriptDocValues<Long> {
 
         public Longs(Supplier<Long> supplier) {

server/src/main/java/org/elasticsearch/index/mapper/SeqNoFieldMapper.java

@@ -17,12 +17,10 @@ import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.IndexNumericFieldData.NumericType;
-import org.elasticsearch.index.fielddata.ScriptDocValues.Longs;
-import org.elasticsearch.index.fielddata.ScriptDocValues.LongsSupplier;
 import org.elasticsearch.index.fielddata.plain.SortedNumericIndexFieldData;
 import org.elasticsearch.index.query.SearchExecutionContext;
 import org.elasticsearch.index.seqno.SequenceNumbers;
-import org.elasticsearch.script.field.DelegateDocValuesField;
+import org.elasticsearch.script.field.SeqNoDocValuesField;
 import org.elasticsearch.search.lookup.SearchLookup;
 
 import java.io.IOException;
@@ -186,11 +184,7 @@ public class SeqNoFieldMapper extends MetadataFieldMapper {
         @Override
         public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, Supplier<SearchLookup> searchLookup) {
             failIfNoDocValues();
-            return new SortedNumericIndexFieldData.Builder(
-                name(),
-                NumericType.LONG,
-                (dv, n) -> new DelegateDocValuesField(new Longs(new LongsSupplier(dv)), n)
-            );
+            return new SortedNumericIndexFieldData.Builder(name(), NumericType.LONG, SeqNoDocValuesField::new);
         }
     }
 

server/src/main/java/org/elasticsearch/index/mapper/VersionFieldMapper.java

@@ -13,12 +13,10 @@ import org.apache.lucene.document.NumericDocValuesField;
 import org.apache.lucene.search.Query;
 import org.elasticsearch.index.fielddata.IndexFieldData;
 import org.elasticsearch.index.fielddata.IndexNumericFieldData.NumericType;
-import org.elasticsearch.index.fielddata.ScriptDocValues.Longs;
-import org.elasticsearch.index.fielddata.ScriptDocValues.LongsSupplier;
 import org.elasticsearch.index.fielddata.plain.SortedNumericIndexFieldData;
 import org.elasticsearch.index.query.QueryShardException;
 import org.elasticsearch.index.query.SearchExecutionContext;
-import org.elasticsearch.script.field.DelegateDocValuesField;
+import org.elasticsearch.script.field.VersionDocValuesField;
 import org.elasticsearch.search.lookup.SearchLookup;
 
 import java.util.Collections;
@@ -60,11 +58,7 @@ public class VersionFieldMapper extends MetadataFieldMapper {
         @Override
         public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, Supplier<SearchLookup> searchLookup) {
             failIfNoDocValues();
-            return new SortedNumericIndexFieldData.Builder(
-                name(),
-                NumericType.LONG,
-                (dv, n) -> new DelegateDocValuesField(new Longs(new LongsSupplier(dv)), n)
-            );
+            return new SortedNumericIndexFieldData.Builder(name(), NumericType.LONG, VersionDocValuesField::new);
         }
     }
 

server/src/main/java/org/elasticsearch/script/field/AbstractLongDocValuesField.java

@@ -0,0 +1,144 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.script.field;
+
+import org.apache.lucene.index.SortedNumericDocValues;
+import org.apache.lucene.util.ArrayUtil;
+import org.elasticsearch.index.fielddata.ScriptDocValues;
+
+import java.io.IOException;
+import java.util.NoSuchElementException;
+import java.util.PrimitiveIterator;
+
+public abstract class AbstractLongDocValuesField implements ScriptDocValues.Supplier<Long>, DocValuesField<Long> {
+
+    protected final String name;
+    // used for backwards compatibility for old-style "doc" access
+    // as a delegate to this field class
+    protected ScriptDocValues<?> scriptDocValues = null;
+
+    protected final SortedNumericDocValues input;
+    protected long[] values = new long[0];
+    protected int count;
+
+    public AbstractLongDocValuesField(SortedNumericDocValues input, String name) {
+        this.input = input;
+        this.name = name;
+    }
+
+    /**
+     * Override if not using {@link ScriptDocValues.Longs}
+     */
+    protected ScriptDocValues<?> newScriptDocValues() {
+        return new ScriptDocValues.Longs(this);
+    }
+
+    /**
+     * Override if long has special formatting.
+     */
+    protected long formatLong(long raw) {
+        return raw;
+    }
+
+    @Override
+    public void setNextDocId(int docId) throws IOException {
+        if (input.advanceExact(docId)) {
+            resize(input.docValueCount());
+            for (int i = 0; i < count; i++) {
+                values[i] = formatLong(input.nextValue());
+            }
+        } else {
+            resize(0);
+        }
+    }
+
+    @Override
+    public ScriptDocValues<?> getScriptDocValues() {
+        if (scriptDocValues == null) {
+            scriptDocValues = newScriptDocValues();
+        }
+
+        return scriptDocValues;
+    }
+
+    /**
+     * Set the {@link #size()} and ensure that the {@link #values} array can
+     * store at least that many entries.
+     */
+    private void resize(int newSize) {
+        count = newSize;
+        values = ArrayUtil.grow(values, count);
+    }
+
+    // this method is required to support the Long return values
+    // for the old-style "doc" access in ScriptDocValues
+    @Override
+    public Long getInternal(int index) {
+        return getLong(index);
+    }
+
+    protected long getLong(int index) {
+        return values[index];
+    }
+
+    @Override
+    public int size() {
+        return count;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return count == 0;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public PrimitiveIterator.OfLong iterator() {
+        return new PrimitiveIterator.OfLong() {
+            private int index = 0;
+
+            @Override
+            public boolean hasNext() {
+                return index < count;
+            }
+
+            @Override
+            public Long next() {
+                return nextLong();
+            }
+
+            @Override
+            public long nextLong() {
+                if (hasNext() == false) {
+                    throw new NoSuchElementException();
+                }
+
+                return getLong(index++);
+            }
+        };
+    }
+
+    /** Returns the 0th index value as an {@code long} if it exists, otherwise {@code defaultValue}. */
+    public long get(long defaultValue) {
+        return get(0, defaultValue);
+    }
+
+    /** Returns the value at {@code index} as an {@code long} if it exists, otherwise {@code defaultValue}. */
+    public long get(int index, long defaultValue) {
+        if (isEmpty() || index < 0 || index >= count) {
+            return defaultValue;
+        }
+
+        return getLong(index);
+    }
+}

server/src/main/java/org/elasticsearch/script/field/LongDocValuesField.java

@@ -9,119 +9,10 @@
 package org.elasticsearch.script.field;
 
 import org.apache.lucene.index.SortedNumericDocValues;
-import org.apache.lucene.util.ArrayUtil;
-import org.elasticsearch.index.fielddata.ScriptDocValues;
 
-import java.io.IOException;
-import java.util.Iterator;
-import java.util.NoSuchElementException;
-
-public class LongDocValuesField implements DocValuesField<Long>, ScriptDocValues.Supplier<Long> {
-
-    protected final SortedNumericDocValues input;
-    protected final String name;
-
-    protected long[] values = new long[0];
-    protected int count;
-
-    private ScriptDocValues.Longs longs = null;
+public class LongDocValuesField extends AbstractLongDocValuesField {
 
     public LongDocValuesField(SortedNumericDocValues input, String name) {
-        this.input = input;
-        this.name = name;
-    }
-
-    @Override
-    public void setNextDocId(int docId) throws IOException {
-        if (input.advanceExact(docId)) {
-            resize(input.docValueCount());
-            for (int i = 0; i < count; i++) {
-                values[i] = input.nextValue();
-            }
-        } else {
-            resize(0);
-        }
-    }
-
-    protected void resize(int newSize) {
-        count = newSize;
-
-        assert count >= 0 : "size must be positive (got " + count + "): likely integer overflow?";
-        values = ArrayUtil.grow(values, count);
-    }
-
-    /**
-     * Returns a {@code ScriptDocValues} of the appropriate type for this field.
-     * This is used to support backwards compatibility for accessing field values
-     * through the {@code doc} variable.
-     */
-    @Override
-    public ScriptDocValues<Long> getScriptDocValues() {
-        if (longs == null) {
-            longs = new ScriptDocValues.Longs(this);
-        }
-
-        return longs;
-    }
-
-    @Override
-    public Long getInternal(int index) {
-        return values[index];
-    }
-
-    /**
-     * Returns the name of this field.
-     */
-    @Override
-    public String getName() {
-        return name;
-    }
-
-    /**
-     * Returns {@code true} if this field has no values, otherwise {@code false}.
-     */
-    @Override
-    public boolean isEmpty() {
-        return count == 0;
-    }
-
-    /**
-     * Returns the number of values this field has.
-     */
-    @Override
-    public int size() {
-        return count;
-    }
-
-    @Override
-    public Iterator<Long> iterator() {
-        return new Iterator<Long>() {
-            private int index = 0;
-
-            @Override
-            public boolean hasNext() {
-                return index < count;
-            }
-
-            @Override
-            public Long next() {
-                if (hasNext() == false) {
-                    throw new NoSuchElementException();
-                }
-                return values[index++];
-            }
-        };
-    }
-
-    public long get(long defaultValue) {
-        return get(0, defaultValue);
-    }
-
-    public long get(int index, long defaultValue) {
-        if (isEmpty() || index < 0 || index >= count) {
-            return defaultValue;
-        }
-
-        return values[index];
+        super(input, name);
     }
 }

server/src/main/java/org/elasticsearch/script/field/SeqNoDocValuesField.java

@@ -0,0 +1,17 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.script.field;
+
+import org.apache.lucene.index.SortedNumericDocValues;
+
+public class SeqNoDocValuesField extends AbstractLongDocValuesField {
+    public SeqNoDocValuesField(SortedNumericDocValues input, String name) {
+        super(input, name);
+    }
+}

server/src/main/java/org/elasticsearch/script/field/VersionDocValuesField.java

@@ -0,0 +1,17 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+package org.elasticsearch.script.field;
+
+import org.apache.lucene.index.SortedNumericDocValues;
+
+public class VersionDocValuesField extends AbstractLongDocValuesField {
+    public VersionDocValuesField(SortedNumericDocValues input, String name) {
+        super(input, name);
+    }
+}

x-pack/plugin/mapper-unsigned-long/src/main/java/org/elasticsearch/xpack/unsignedlong/UnsignedLongDocValuesField.java

@@ -8,92 +8,35 @@
 package org.elasticsearch.xpack.unsignedlong;
 
 import org.apache.lucene.index.SortedNumericDocValues;
-import org.apache.lucene.util.ArrayUtil;
 import org.elasticsearch.index.fielddata.ScriptDocValues;
-import org.elasticsearch.script.field.DocValuesField;
+import org.elasticsearch.script.field.AbstractLongDocValuesField;
 
-import java.io.IOException;
 import java.math.BigInteger;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.NoSuchElementException;
-import java.util.PrimitiveIterator;
 
 import static org.elasticsearch.search.DocValueFormat.MASK_2_63;
 import static org.elasticsearch.xpack.unsignedlong.UnsignedLongFieldMapper.BIGINTEGER_2_64_MINUS_ONE;
 
-public class UnsignedLongDocValuesField implements DocValuesField<Long>, ScriptDocValues.Supplier<Long> {
-
-    private final SortedNumericDocValues input;
-    private final String name;
-
-    private long[] values = new long[0];
-    private int count = 0;
-
-    // used for backwards compatibility for old-style "doc" access
-    // as a delegate to this field class
-    private UnsignedLongScriptDocValues unsignedLongScriptDocValues = null;
+public class UnsignedLongDocValuesField extends AbstractLongDocValuesField {
 
     public UnsignedLongDocValuesField(SortedNumericDocValues input, String name) {
-        this.input = input;
-        this.name = name;
-    }
-
-    @Override
-    public void setNextDocId(int docId) throws IOException {
-        if (input.advanceExact(docId)) {
-            resize(input.docValueCount());
-            for (int i = 0; i < count; i++) {
-                values[i] = input.nextValue();
-            }
-        } else {
-            resize(0);
-        }
-    }
-
-    private void resize(int newSize) {
-        count = newSize;
-        values = ArrayUtil.grow(values, count);
-    }
-
-    @Override
-    public ScriptDocValues<?> getScriptDocValues() {
-        if (unsignedLongScriptDocValues == null) {
-            unsignedLongScriptDocValues = new UnsignedLongScriptDocValues(this);
-        }
-
-        return unsignedLongScriptDocValues;
-    }
-
-    @Override
-    public String getName() {
-        return name;
-    }
-
-    @Override
-    public boolean isEmpty() {
-        return count == 0;
+        super(input, name);
     }
 
-    // this method is required to support the Long return values
-    // for the old-style "doc" access in ScriptDocValues
     @Override
-    public Long getInternal(int index) {
-        return toFormatted(index);
-    }
-
-    @Override
-    public int size() {
-        return count;
+    public ScriptDocValues<?> newScriptDocValues() {
+        return new UnsignedLongScriptDocValues(this);
     }
 
     /**
      * Applies the formatting from {@link org.elasticsearch.search.DocValueFormat.UnsignedLongShiftedDocValueFormat#format(long)} so
      * that the underlying value can be treated as a primitive long as that method returns either a {@code long} or a {@code BigInteger}.
      */
-    protected long toFormatted(int index) {
-        return values[index] ^ MASK_2_63;
+    @Override
+    protected long formatLong(long raw) {
+        return raw ^ MASK_2_63;
     }
 
     /** Return all the values as a {@code List}. */
@@ -105,26 +48,12 @@ public class UnsignedLongDocValuesField implements DocValuesField<Long>, ScriptD
         List<Long> longValues = new ArrayList<>(count);
 
         for (int index = 0; index < count; ++index) {
-            longValues.add(toFormatted(index));
+            longValues.add(getLong(index));
         }
 
         return longValues;
     }
 
-    /** Returns the 0th index value as an {@code long} if it exists, otherwise {@code defaultValue}. */
-    public long get(long defaultValue) {
-        return get(0, defaultValue);
-    }
-
-    /** Returns the value at {@code index} as an {@code long} if it exists, otherwise {@code defaultValue}. */
-    public long get(int index, long defaultValue) {
-        if (isEmpty() || index < 0 || index >= count) {
-            return defaultValue;
-        }
-
-        return toFormatted(index);
-    }
-
     /** Returns the 0th index value as an {@code long} if it exists, otherwise {@code defaultValue}. */
     public long getValue(long defaultValue) {
         return get(0, defaultValue);
@@ -135,34 +64,8 @@ public class UnsignedLongDocValuesField implements DocValuesField<Long>, ScriptD
         return get(index, defaultValue);
     }
 
-    @Override
-    public PrimitiveIterator.OfLong iterator() {
-        return new PrimitiveIterator.OfLong() {
-            private int index = 0;
-
-            @Override
-            public boolean hasNext() {
-                return index < count;
-            }
-
-            @Override
-            public Long next() {
-                return nextLong();
-            }
-
-            @Override
-            public long nextLong() {
-                if (hasNext() == false) {
-                    throw new NoSuchElementException();
-                }
-
-                return toFormatted(index++);
-            }
-        };
-    }
-
     protected BigInteger toBigInteger(int index) {
-        return BigInteger.valueOf(toFormatted(index)).and(BIGINTEGER_2_64_MINUS_ONE);
+        return BigInteger.valueOf(getLong(index)).and(BIGINTEGER_2_64_MINUS_ONE);
     }
 
     /** Converts all the values to {@code BigInteger} and returns them as a {@code List}. */

x-pack/plugin/mapper-version/build.gradle

@@ -1,11 +1,14 @@
 evaluationDependsOn(xpackModule('core'))
 
+
 apply plugin: 'elasticsearch.internal-es-plugin'
+apply plugin: 'elasticsearch.internal-yaml-rest-test'
+apply plugin: 'elasticsearch.yaml-rest-compat-test'
 apply plugin: 'elasticsearch.internal-cluster-test'
 
 esplugin {
   name 'mapper-version'
-  description 'A plugin for a field type to store sofware versions'
+  description 'A plugin for a field type to store software versions'
   classname 'org.elasticsearch.xpack.versionfield.VersionFieldPlugin'
   extendedPlugins = ['x-pack-core', 'lang-painless']
 }

x-pack/plugin/mapper-version/src/main/java/org/elasticsearch/xpack/versionfield/Version.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.xpack.versionfield;
+
+import org.elasticsearch.xcontent.ToXContent;
+import org.elasticsearch.xcontent.XContentBuilder;
+
+import java.io.IOException;
+
+/**
+ * Script value class.
+ * TODO(stu): implement {@code Comparable<Version>} based on {@code VersionEncoder#prefixDigitGroupsWithLength(String, BytesRefBuilder)}
+ * See: https://github.com/elastic/elasticsearch/issues/82287
+ */
+public class Version implements ToXContent {
+    protected String version;
+
+    public Version(String version) {
+        this.version = version;
+    }
+
+    @Override
+    public String toString() {
+        return version;
+    }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return builder.value(toString());
+    }
+
+    @Override
+    public boolean isFragment() {
+        return false;
+    }
+}

x-pack/plugin/mapper-version/src/main/java/org/elasticsearch/xpack/versionfield/VersionFieldDocValuesExtension.java

@@ -26,7 +26,10 @@ import static java.util.Collections.singletonList;
 
 public class VersionFieldDocValuesExtension implements PainlessExtension {
 
-    private static final Whitelist WHITELIST = WhitelistLoader.loadFromResourceFiles(VersionFieldDocValuesExtension.class, "whitelist.txt");
+    private static final Whitelist WHITELIST = WhitelistLoader.loadFromResourceFiles(
+        VersionFieldDocValuesExtension.class,
+        "org.elasticsearch.xpack.versionfield.txt"
+    );
 
     @Override
     public Map<ScriptContext<?>, List<Whitelist>> getContextWhitelists() {

x-pack/plugin/mapper-version/src/main/java/org/elasticsearch/xpack/versionfield/VersionScriptDocValues.java

@@ -7,51 +7,11 @@
 
 package org.elasticsearch.xpack.versionfield;
 
-import org.apache.lucene.index.SortedSetDocValues;
-import org.apache.lucene.util.ArrayUtil;
 import org.elasticsearch.index.fielddata.ScriptDocValues;
 
-import java.io.IOException;
-
 public final class VersionScriptDocValues extends ScriptDocValues<String> {
 
-    public static final class VersionScriptSupplier implements ScriptDocValues.Supplier<String> {
-
-        private final SortedSetDocValues in;
-        private long[] ords = new long[0];
-        private int count;
-
-        public VersionScriptSupplier(SortedSetDocValues in) {
-            this.in = in;
-        }
-
-        @Override
-        public void setNextDocId(int docId) throws IOException {
-            count = 0;
-            if (in.advanceExact(docId)) {
-                for (long ord = in.nextOrd(); ord != SortedSetDocValues.NO_MORE_ORDS; ord = in.nextOrd()) {
-                    ords = ArrayUtil.grow(ords, count + 1);
-                    ords[count++] = ord;
-                }
-            }
-        }
-
-        @Override
-        public String getInternal(int index) {
-            try {
-                return VersionEncoder.decodeVersion(in.lookupOrd(ords[index]));
-            } catch (IOException e) {
-                throw new RuntimeException(e);
-            }
-        }
-
-        @Override
-        public int size() {
-            return count;
-        }
-    }
-
-    public VersionScriptDocValues(VersionScriptSupplier supplier) {
+    public VersionScriptDocValues(Supplier<String> supplier) {
         super(supplier);
     }
 

x-pack/plugin/mapper-version/src/main/java/org/elasticsearch/xpack/versionfield/VersionStringDocValuesField.java

@@ -0,0 +1,144 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.xpack.versionfield;
+
+import org.apache.lucene.index.SortedSetDocValues;
+import org.apache.lucene.util.ArrayUtil;
+import org.elasticsearch.index.fielddata.ScriptDocValues;
+import org.elasticsearch.script.field.DocValuesField;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+public class VersionStringDocValuesField implements DocValuesField<Version>, ScriptDocValues.Supplier<String> {
+
+    protected final SortedSetDocValues input;
+    protected final String name;
+
+    protected long[] ords = new long[0];
+    protected int count;
+
+    // used for backwards compatibility for old-style "doc" access
+    // as a delegate to this field class
+    private VersionScriptDocValues versionScriptDocValues = null;
+
+    public VersionStringDocValuesField(SortedSetDocValues input, String name) {
+        this.input = input;
+        this.name = name;
+    }
+
+    @Override
+    public void setNextDocId(int docId) throws IOException {
+        count = 0;
+        if (input.advanceExact(docId)) {
+            for (long ord = input.nextOrd(); ord != SortedSetDocValues.NO_MORE_ORDS; ord = input.nextOrd()) {
+                ords = ArrayUtil.grow(ords, count + 1);
+                ords[count++] = ord;
+            }
+        }
+    }
+
+    @Override
+    public String getInternal(int index) {
+        try {
+            return VersionEncoder.decodeVersion(input.lookupOrd(ords[index]));
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    public int size() {
+        return count;
+    }
+
+    @Override
+    public ScriptDocValues<?> getScriptDocValues() {
+        if (versionScriptDocValues == null) {
+            versionScriptDocValues = new VersionScriptDocValues(this);
+        }
+
+        return versionScriptDocValues;
+    }
+
+    public String asString(String defaultValue) {
+        return asString(0, defaultValue);
+    }
+
+    public String asString(int index, String defaultValue) {
+        if (isEmpty() || index < 0 || index >= size()) {
+            return defaultValue;
+        }
+
+        return getInternal(index);
+    }
+
+    public List<String> asStrings() {
+        if (isEmpty()) {
+            return Collections.emptyList();
+        }
+
+        List<String> values = new ArrayList<>(size());
+        for (int i = 0; i < size(); i++) {
+            values.add(getInternal(i));
+        }
+
+        return values;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+
+    @Override
+    public boolean isEmpty() {
+        return count == 0;
+    }
+
+    public Version get(Version defaultValue) {
+        return get(0, defaultValue);
+    }
+
+    public Version get(int index, Version defaultValue) {
+        if (isEmpty() || index < 0 || index >= size()) {
+            return defaultValue;
+        }
+
+        return new Version(getInternal(index));
+    }
+
+    /**
+     * Returns an iterator over elements of type {@code T}.
+     *
+     * @return an Iterator.
+     */
+    @Override
+    public Iterator<Version> iterator() {
+        return new Iterator<Version>() {
+            private int index = 0;
+
+            @Override
+            public boolean hasNext() {
+                return index < size();
+            }
+
+            @Override
+            public Version next() {
+                if (hasNext() == false) {
+                    throw new NoSuchElementException();
+                }
+                return new Version(getInternal(index++));
+            }
+        };
+    }
+}

x-pack/plugin/mapper-version/src/main/java/org/elasticsearch/xpack/versionfield/VersionStringFieldMapper.java

@@ -44,7 +44,6 @@ import org.elasticsearch.index.mapper.TextSearchInfo;
 import org.elasticsearch.index.mapper.ValueFetcher;
 import org.elasticsearch.index.query.SearchExecutionContext;
 import org.elasticsearch.index.query.support.QueryParsers;
-import org.elasticsearch.script.field.DelegateDocValuesField;
 import org.elasticsearch.search.DocValueFormat;
 import org.elasticsearch.search.aggregations.support.CoreValuesSourceType;
 import org.elasticsearch.search.lookup.SearchLookup;
@@ -63,7 +62,6 @@ import java.util.function.Supplier;
 
 import static org.elasticsearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
 import static org.elasticsearch.xpack.versionfield.VersionEncoder.encodeVersion;
-import static org.elasticsearch.xpack.versionfield.VersionScriptDocValues.VersionScriptSupplier;
 
 /**
  * A {@link FieldMapper} for indexing fields with version strings.
@@ -281,11 +279,7 @@ public class VersionStringFieldMapper extends FieldMapper {
 
         @Override
         public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName, Supplier<SearchLookup> searchLookup) {
-            return new SortedSetOrdinalsIndexFieldData.Builder(
-                name(),
-                CoreValuesSourceType.KEYWORD,
-                (dv, n) -> new DelegateDocValuesField(new VersionScriptDocValues(new VersionScriptSupplier(dv)), n)
-            );
+            return new SortedSetOrdinalsIndexFieldData.Builder(name(), CoreValuesSourceType.KEYWORD, VersionStringDocValuesField::new);
         }
 
         @Override

x-pack/plugin/mapper-version/src/main/resources/org/elasticsearch/xpack/versionfield/org.elasticsearch.xpack.versionfield.txt

@@ -0,0 +1,24 @@
+#
+# Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+# or more contributor license agreements. Licensed under the Elastic License
+# 2.0 and the Server Side Public License, v 1; you may not use this file except
+# in compliance with, at your election, the Elastic License 2.0 or the Server
+# Side Public License, v 1.
+#
+
+class org.elasticsearch.xpack.versionfield.VersionScriptDocValues {
+    String get(int)
+    String getValue()
+}
+
+class org.elasticsearch.xpack.versionfield.Version {
+    (String)
+}
+
+class org.elasticsearch.xpack.versionfield.VersionStringDocValuesField @dynamic_type {
+    String asString(String)
+    String asString(int, String)
+    List asStrings()
+    Version get(Version)
+    Version get(int, Version)
+}

x-pack/plugin/mapper-version/src/main/resources/org/elasticsearch/xpack/versionfield/whitelist.txt

@@ -1,5 +0,0 @@
-
-class org.elasticsearch.xpack.versionfield.VersionScriptDocValues {
-    String get(int)
-    String getValue()
-}

x-pack/plugin/mapper-version/src/yamlRestTest/java/org/elasticsearch/xpack/versionfield/VersionClientYamlTestSuiteIT.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0; you may not use this file except in compliance with the Elastic License
+ * 2.0.
+ */
+
+package org.elasticsearch.xpack.versionfield;
+
+import com.carrotsearch.randomizedtesting.annotations.Name;
+import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
+
+import org.elasticsearch.test.rest.yaml.ClientYamlTestCandidate;
+import org.elasticsearch.test.rest.yaml.ESClientYamlSuiteTestCase;
+
+/** Runs yaml rest tests */
+public class VersionClientYamlTestSuiteIT extends ESClientYamlSuiteTestCase {
+
+    public VersionClientYamlTestSuiteIT(@Name("yaml") ClientYamlTestCandidate testCandidate) {
+        super(testCandidate);
+    }
+
+    @ParametersFactory
+    public static Iterable<Object[]> parameters() throws Exception {
+        return ESClientYamlSuiteTestCase.createParameters();
+    }
+}

x-pack/plugin/mapper-version/src/yamlRestTest/resources/rest-api-spec/test/50_script_values.yml

@@ -0,0 +1,45 @@
+setup:
+
+  - skip:
+      version: " - 8.0.99"
+      reason: "version script field support was added in 8.1.0"
+
+  - do:
+      indices.create:
+        index:  test1
+        body:
+          mappings:
+            properties:
+              ver:
+                type: version
+
+  - do:
+      bulk:
+        index: test1
+        refresh: true
+        body: |
+          { "index": {"_id" : "1"} }
+          { "ver": "1.0.0" }
+          { "index": {"_id" : "2"} }
+          { "ver": "1.2.3-abc+def" }
+          { "index": {"_id" : "3"} }
+          { "ver": "1.2.3.4.5" }
+          { "index": {"_id" : "4"} }
+          { "ver": ["6.7.8", "5.4.3"] }
+
+---
+"Scripted fields version values return Version":
+  - do:
+      search:
+        index: test1
+        body:
+          sort: [ { ver: desc } ]
+          script_fields:
+            field:
+              script:
+                source: "field('ver').get(new Version(''))"
+
+  - match: { hits.hits.0.fields.field.0: "5.4.3" }
+  - match: { hits.hits.1.fields.field.0: "1.2.3.4.5" }
+  - match: { hits.hits.2.fields.field.0: "1.2.3-abc+def" }
+  - match: { hits.hits.3.fields.field.0: "1.0.0" }