Revert "Convert double script to return array (#61504)"

This reverts commit 6d8170c. We've
decided to stick with the `value` style functions for runtime fields.

x-pack/plugin/runtime-fields/qa/rest/src/yamlRestTest/java/org/elasticsearch/xpack/runtimefields/rest/CoreTestsWithRuntimeFieldsIT.java

@@ -166,9 +166,6 @@ private static String painlessToLoadFromSource(String name, String type) {
             return null;
         }
         StringBuilder b = new StringBuilder();
-        if ("double".equals(type)) {
-            b.append("List result = new ArrayList();");
-        }
         b.append("def v = source['").append(name).append("'];\n");
         b.append("if (v instanceof Iterable) {\n");
         b.append("  for (def vv : ((Iterable) v)) {\n");
@@ -183,9 +180,6 @@ private static String painlessToLoadFromSource(String name, String type) {
         b.append("    ").append(emit).append("\n");
         b.append("  }\n");
         b.append("}\n");
-        if ("double".equals(type)) {
-            b.append("return result;");
-        }
         return b.toString();
     }
 
@@ -194,7 +188,7 @@ private static String painlessToLoadFromSource(String name, String type) {
         Map.entry(DateFieldMapper.CONTENT_TYPE, "millis(parse(value.toString()));"),
         Map.entry(
             NumberType.DOUBLE.typeName(),
-            "result.add(value instanceof Number ? ((Number) value).doubleValue() : Double.parseDouble(value.toString()));"
+            "value(value instanceof Number ? ((Number) value).doubleValue() : Double.parseDouble(value.toString()));"
         ),
         Map.entry(KeywordFieldMapper.CONTENT_TYPE, "value(value.toString());"),
         Map.entry(IpFieldMapper.CONTENT_TYPE, "stringValue(value.toString());"),

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/AbstractLongScriptFieldScript.java

@@ -23,8 +23,6 @@ public AbstractLongScriptFieldScript(Map<String, Object> params, SearchLookup se
         super(params, searchLookup, ctx);
     }
 
-    public abstract void execute();
-
     /**
      * Execute the script for the provided {@code docId}.
      */

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/AbstractScriptFieldScript.java

@@ -81,4 +81,6 @@ public final Map<String, Object> getSource() {
     public final Map<String, ScriptDocValues<?>> getDoc() {
         return leafSearchLookup.doc();
     }
+
+    public abstract void execute();
 }

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/BooleanScriptFieldScript.java

@@ -42,8 +42,6 @@ public BooleanScriptFieldScript(Map<String, Object> params, SearchLookup searchL
         super(params, searchLookup, ctx);
     }
 
-    public abstract void execute();
-
     /**
      * Execute the script for the provided {@code docId}.
      */

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/DoubleScriptFieldScript.java

@@ -7,14 +7,14 @@
 package org.elasticsearch.xpack.runtimefields;
 
 import org.apache.lucene.index.LeafReaderContext;
+import org.apache.lucene.util.ArrayUtil;
 import org.elasticsearch.painless.spi.Whitelist;
 import org.elasticsearch.painless.spi.WhitelistLoader;
 import org.elasticsearch.script.ScriptContext;
 import org.elasticsearch.script.ScriptFactory;
 import org.elasticsearch.search.lookup.SearchLookup;
 
 import java.io.IOException;
-import java.util.Collection;
 import java.util.List;
 import java.util.Map;
 
@@ -35,40 +35,55 @@ public interface LeafFactory {
         DoubleScriptFieldScript newInstance(LeafReaderContext ctx) throws IOException;
     }
 
+    private double[] values = new double[1];
+    private int count;
+
     public DoubleScriptFieldScript(Map<String, Object> params, SearchLookup searchLookup, LeafReaderContext ctx) {
         super(params, searchLookup, ctx);
     }
 
-    public abstract double[] execute();
-
     /**
      * Execute the script for the provided {@code docId}.
      */
-    public final double[] runForDoc(int docId) {
+    public final void runForDoc(int docId) {
+        count = 0;
         setDocument(docId);
-        return execute();
+        execute();
     }
 
-    public static double[] convertFromDouble(double v) {
-        return new double[] { v };
+    /**
+     * Values from the last time {@link #runForDoc(int)} was called. This array
+     * is mutable and will change with the next call of {@link #runForDoc(int)}.
+     * It is also oversized and will contain garbage at all indices at and
+     * above {@link #count()}.
+     */
+    public final double[] values() {
+        return values;
     }
 
-    public static double[] convertFromCollection(Collection<?> v) {
-        double[] result = new double[v.size()];
-        int i = 0;
-        for (Object o : v) {
-            result[i++] = ((Number) o).doubleValue();
+    /**
+     * The number of results produced the last time {@link #runForDoc(int)} was called.
+     */
+    public final int count() {
+        return count;
+    }
+
+    private void collectValue(double v) {
+        if (values.length < count + 1) {
+            values = ArrayUtil.grow(values, count + 1);
         }
-        return result;
+        values[count++] = v;
     }
 
-    public static double[] convertFromDef(Object o) {
-        if (o instanceof Number) {
-            return convertFromDouble(((Number) o).doubleValue());
-        } else if (o instanceof Collection) {
-            return convertFromCollection((Collection<?>) o);
-        } else {
-            return (double[]) o;
+    public static class Value {
+        private final DoubleScriptFieldScript script;
+
+        public Value(DoubleScriptFieldScript script) {
+            this.script = script;
+        }
+
+        public void value(double v) {
+            script.collectValue(v);
         }
     }
 }

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/IpScriptFieldScript.java

@@ -63,8 +63,6 @@ public IpScriptFieldScript(Map<String, Object> params, SearchLookup searchLookup
         super(params, searchLookup, ctx);
     }
 
-    public abstract void execute();
-
     /**
      * Execute the script for the provided {@code docId}.
      */

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/StringScriptFieldScript.java

@@ -41,8 +41,6 @@ public StringScriptFieldScript(Map<String, Object> params, SearchLookup searchLo
         super(params, searchLookup, ctx);
     }
 
-    public abstract void execute();
-
     /**
      * Execute the script for the provided {@code docId}.
      * <p>

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/fielddata/ScriptDoubleDocValues.java

@@ -14,7 +14,6 @@
 
 public final class ScriptDoubleDocValues extends SortedNumericDoubleValues {
     private final DoubleScriptFieldScript script;
-    private double[] values;
     private int cursor;
 
     ScriptDoubleDocValues(DoubleScriptFieldScript script) {
@@ -23,22 +22,22 @@ public final class ScriptDoubleDocValues extends SortedNumericDoubleValues {
 
     @Override
     public boolean advanceExact(int docId) {
-        values = script.runForDoc(docId);
-        if (values.length == 0) {
+        script.runForDoc(docId);
+        if (script.count() == 0) {
             return false;
         }
-        Arrays.sort(values);
+        Arrays.sort(script.values(), 0, script.count());
         cursor = 0;
         return true;
     }
 
     @Override
     public double nextValue() throws IOException {
-        return values[cursor++];
+        return script.values()[cursor++];
     }
 
     @Override
     public int docValueCount() {
-        return values.length;
+        return script.count();
     }
 }

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/query/AbstractDoubleScriptFieldQuery.java

@@ -36,7 +36,7 @@ abstract class AbstractDoubleScriptFieldQuery extends AbstractScriptFieldQuery {
     /**
      * Does the value match this query?
      */
-    protected abstract boolean matches(double[] values);
+    protected abstract boolean matches(double[] values, int count);
 
     @Override
     public final Weight createWeight(IndexSearcher searcher, ScoreMode scoreMode, float boost) throws IOException {
@@ -53,7 +53,8 @@ public Scorer scorer(LeafReaderContext ctx) throws IOException {
                 TwoPhaseIterator twoPhase = new TwoPhaseIterator(approximation) {
                     @Override
                     public boolean matches() throws IOException {
-                        return AbstractDoubleScriptFieldQuery.this.matches(script.runForDoc(approximation().docID()));
+                        script.runForDoc(approximation().docID());
+                        return AbstractDoubleScriptFieldQuery.this.matches(script.values(), script.count());
                     }
 
                     @Override

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/query/DoubleScriptFieldExistsQuery.java

@@ -15,8 +15,8 @@ public DoubleScriptFieldExistsQuery(Script script, DoubleScriptFieldScript.LeafF
     }
 
     @Override
-    protected boolean matches(double[] values) {
-        return values.length > 0;
+    protected boolean matches(double[] values, int count) {
+        return count > 0;
     }
 
     @Override

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/query/DoubleScriptFieldRangeQuery.java

@@ -29,9 +29,9 @@ public DoubleScriptFieldRangeQuery(
     }
 
     @Override
-    protected boolean matches(double[] values) {
-        for (double value : values) {
-            if (lowerValue <= value && value <= upperValue) {
+    protected boolean matches(double[] values, int count) {
+        for (int i = 0; i < count; i++) {
+            if (lowerValue <= values[i] && values[i] <= upperValue) {
                 return true;
             }
         }

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/query/DoubleScriptFieldTermQuery.java

@@ -20,9 +20,9 @@ public DoubleScriptFieldTermQuery(Script script, DoubleScriptFieldScript.LeafFac
     }
 
     @Override
-    protected boolean matches(double[] values) {
-        for (double value : values) {
-            if (term == value) {
+    protected boolean matches(double[] values, int count) {
+        for (int i = 0; i < count; i++) {
+            if (term == values[i]) {
                 return true;
             }
         }

x-pack/plugin/runtime-fields/src/main/java/org/elasticsearch/xpack/runtimefields/query/DoubleScriptFieldTermsQuery.java

@@ -29,9 +29,9 @@ public DoubleScriptFieldTermsQuery(Script script, DoubleScriptFieldScript.LeafFa
     }
 
     @Override
-    protected boolean matches(double[] values) {
-        for (double value : values) {
-            if (terms.contains(Double.doubleToLongBits(value))) {
+    protected boolean matches(double[] values, int count) {
+        for (int i = 0; i < count; i++) {
+            if (terms.contains(Double.doubleToLongBits(values[i]))) {
                 return true;
             }
         }

x-pack/plugin/runtime-fields/src/main/resources/org/elasticsearch/xpack/runtimefields/double_whitelist.txt

@@ -9,6 +9,10 @@
 class org.elasticsearch.xpack.runtimefields.DoubleScriptFieldScript @no_import {
 }
 
-# This whitelist is required to allow painless to build the factory
+static_import {
+    void value(org.elasticsearch.xpack.runtimefields.DoubleScriptFieldScript, double) bound_to org.elasticsearch.xpack.runtimefields.DoubleScriptFieldScript$Value
+}
+
+# This import is required to make painless happy and it isn't 100% clear why
 class org.elasticsearch.xpack.runtimefields.DoubleScriptFieldScript$Factory @no_import {
 }

x-pack/plugin/runtime-fields/src/test/java/org/elasticsearch/xpack/runtimefields/DoubleScriptFieldScriptTests.java

@@ -8,19 +8,15 @@
 
 import org.elasticsearch.script.ScriptContext;
 
-import java.util.List;
-
-import static org.hamcrest.Matchers.equalTo;
-
 public class DoubleScriptFieldScriptTests extends ScriptFieldScriptTestCase<DoubleScriptFieldScript.Factory> {
     public static final DoubleScriptFieldScript.Factory DUMMY = (params, lookup) -> ctx -> new DoubleScriptFieldScript(
         params,
         lookup,
         ctx
     ) {
         @Override
-        public double[] execute() {
-            return new double[] { 1.0 };
+        public void execute() {
+            new DoubleScriptFieldScript.Value(this).value(1.0);
         }
     };
 
@@ -33,29 +29,4 @@ protected ScriptContext<DoubleScriptFieldScript.Factory> context() {
     protected DoubleScriptFieldScript.Factory dummyScript() {
         return DUMMY;
     }
-
-    public void testConvertDouble() {
-        double v = randomDouble();
-        assertThat(DoubleScriptFieldScript.convertFromDouble(v), equalTo(new double[] { v }));
-        assertThat(DoubleScriptFieldScript.convertFromDef(v), equalTo(new double[] { v }));
-    }
-
-    public void testConvertFromCollection() {
-        double d = randomDouble();
-        long l = randomLong();
-        int i = randomInt();
-        assertThat(DoubleScriptFieldScript.convertFromCollection(List.of(d, l, i)), equalTo(new double[] { d, l, i }));
-        assertThat(DoubleScriptFieldScript.convertFromDef(List.of(d, l, i)), equalTo(new double[] { d, l, i }));
-    }
-
-    public void testConvertDoubleArrayFromDef() {
-        double[] a = new double[] { 1, 2, 3 };
-        assertThat(DoubleScriptFieldScript.convertFromDef(a), equalTo(a));
-    }
-
-    public void testConvertNumberFromDef() {
-        for (Number n : new Number[] { randomByte(), randomShort(), randomInt(), randomLong(), randomFloat() }) {
-            assertThat(DoubleScriptFieldScript.convertFromDef(n), equalTo(new double[] { n.doubleValue() }));
-        }
-    }
 }

x-pack/plugin/runtime-fields/src/test/java/org/elasticsearch/xpack/runtimefields/mapper/ScriptDoubleMappedFieldTypeTests.java

@@ -270,27 +270,21 @@ private DoubleScriptFieldScript.Factory factory(String code) {
                             case "read_foo":
                                 return (params, lookup) -> (ctx) -> new DoubleScriptFieldScript(params, lookup, ctx) {
                                     @Override
-                                    public double[] execute() {
-                                        List<?> foos = (List<?>) getSource().get("foo");
-                                        double[] results = new double[foos.size()];
-                                        int i = 0;
-                                        for (Object foo : foos) {
-                                            results[i++] = ((Number) foo).doubleValue();
+                                    public void execute() {
+                                        for (Object foo : (List<?>) getSource().get("foo")) {
+                                            new DoubleScriptFieldScript.Value(this).value(((Number) foo).doubleValue());
                                         }
-                                        return results;
                                     }
                                 };
                             case "add_param":
                                 return (params, lookup) -> (ctx) -> new DoubleScriptFieldScript(params, lookup, ctx) {
                                     @Override
-                                    public double[] execute() {
-                                        List<?> foos = (List<?>) getSource().get("foo");
-                                        double[] results = new double[foos.size()];
-                                        int i = 0;
-                                        for (Object foo : foos) {
-                                            results[i++] = ((Number) getParams().get("param")).doubleValue() + ((Number) foo).doubleValue();
+                                    public void execute() {
+                                        for (Object foo : (List<?>) getSource().get("foo")) {
+                                            new DoubleScriptFieldScript.Value(this).value(
+                                                ((Number) foo).doubleValue() + ((Number) getParams().get("param")).doubleValue()
+                                            );
                                         }
-                                        return results;
                                     }
                                 };
                             default:

x-pack/plugin/runtime-fields/src/test/java/org/elasticsearch/xpack/runtimefields/query/DoubleScriptFieldExistsQueryTests.java

@@ -29,13 +29,9 @@ protected DoubleScriptFieldExistsQuery mutate(DoubleScriptFieldExistsQuery orig)
 
     @Override
     public void testMatches() {
-        assertTrue(createTestInstance().matches(new double[] { 1 }));
-        assertFalse(createTestInstance().matches(new double[0]));
-        double[] big = new double[between(1, 10000)];
-        for (int i = 0; i < big.length; i++) {
-            big[i] = 1.0;
-        }
-        assertTrue(createTestInstance().matches(big));
+        assertTrue(createTestInstance().matches(new double[0], randomIntBetween(1, Integer.MAX_VALUE)));
+        assertFalse(createTestInstance().matches(new double[0], 0));
+        assertFalse(createTestInstance().matches(new double[] { 1, 2, 3 }, 0));
     }
 
     @Override