Scripting: ScriptFactory not required by compile (#50344) (#50392)

Avoid backwards incompatible changes for 8.x and 7.6 by removing type
restriction on compile and Factory.  Factories may optionally implement
ScriptFactory.  If so, then they can indicate determinism and thus
cacheability.

**Backport**

Relates: #49466

Author: stu-elastic

modules/analysis-common/src/main/java/org/elasticsearch/analysis/common/AnalysisPredicateScript.java

@@ -27,7 +27,6 @@
 import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
 import org.apache.lucene.util.AttributeSource;
 import org.elasticsearch.script.ScriptContext;
-import org.elasticsearch.script.ScriptFactory;
 
 /**
  * A predicate based on the current token in a TokenStream
@@ -108,7 +107,7 @@ public boolean isKeyword() {
      */
     public abstract boolean execute(Token token);
 
-    public interface Factory extends ScriptFactory {
+    public interface Factory {
         AnalysisPredicateScript newInstance();
     }
 

modules/analysis-common/src/test/java/org/elasticsearch/analysis/common/PredicateTokenScriptFilterTests.java

@@ -30,7 +30,6 @@
 import org.elasticsearch.indices.analysis.AnalysisModule;
 import org.elasticsearch.script.Script;
 import org.elasticsearch.script.ScriptContext;
-import org.elasticsearch.script.ScriptFactory;
 import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.test.ESTokenStreamTestCase;
 import org.elasticsearch.test.IndexSettingsModule;
@@ -64,7 +63,7 @@ public boolean execute(Token token) {
         @SuppressWarnings("unchecked")
         ScriptService scriptService = new ScriptService(indexSettings, Collections.emptyMap(), Collections.emptyMap()){
             @Override
-            public <FactoryType extends ScriptFactory> FactoryType compile(Script script, ScriptContext<FactoryType> context) {
+            public <FactoryType> FactoryType compile(Script script, ScriptContext<FactoryType> context) {
                 assertEquals(context, AnalysisPredicateScript.CONTEXT);
                 assertEquals(new Script("my_script"), script);
                 return (FactoryType) factory;

modules/analysis-common/src/test/java/org/elasticsearch/analysis/common/ScriptedConditionTokenFilterTests.java

@@ -30,7 +30,6 @@
 import org.elasticsearch.indices.analysis.AnalysisModule;
 import org.elasticsearch.script.Script;
 import org.elasticsearch.script.ScriptContext;
-import org.elasticsearch.script.ScriptFactory;
 import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.test.ESTokenStreamTestCase;
 import org.elasticsearch.test.IndexSettingsModule;
@@ -64,7 +63,7 @@ public boolean execute(Token token) {
         @SuppressWarnings("unchecked")
         ScriptService scriptService = new ScriptService(indexSettings, Collections.emptyMap(), Collections.emptyMap()){
             @Override
-            public <FactoryType extends ScriptFactory> FactoryType compile(Script script, ScriptContext<FactoryType> context) {
+            public <FactoryType> FactoryType compile(Script script, ScriptContext<FactoryType> context) {
                 assertEquals(context, AnalysisPredicateScript.CONTEXT);
                 assertEquals(new Script("token.getPosition() > 1"), script);
                 return (FactoryType) factory;

modules/lang-expression/src/main/java/org/elasticsearch/script/expression/ExpressionScriptEngine.java

@@ -44,7 +44,6 @@
 import org.elasticsearch.script.ScriptContext;
 import org.elasticsearch.script.ScriptEngine;
 import org.elasticsearch.script.ScriptException;
-import org.elasticsearch.script.ScriptFactory;
 import org.elasticsearch.script.TermsSetQueryScript;
 import org.elasticsearch.search.lookup.SearchLookup;
 
@@ -88,33 +87,83 @@ public boolean execute() {
                 return wrappedFactory; });
 
         contexts.put(FilterScript.CONTEXT,
-            (Expression expr) -> (FilterScript.Factory) (p, lookup) -> newFilterScript(expr, lookup, p));
+            (Expression expr) -> new FilterScript.Factory() {
+                @Override
+                public boolean isResultDeterministic() {
+                    return true;
+                }
+
+                @Override
+                public FilterScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup) {
+                    return newFilterScript(expr, lookup, params);
+                }
+            });
 
         contexts.put(ScoreScript.CONTEXT,
-            (Expression expr) -> (ScoreScript.Factory) (p, lookup) -> newScoreScript(expr, lookup, p));
+            (Expression expr) -> new ScoreScript.Factory() {
+                @Override
+                public ScoreScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup) {
+                    return newScoreScript(expr, lookup, params);
+                }
+
+                @Override
+                public boolean isResultDeterministic() {
+                    return true;
+                }
+            });
 
         contexts.put(TermsSetQueryScript.CONTEXT,
             (Expression expr) -> (TermsSetQueryScript.Factory) (p, lookup) -> newTermsSetQueryScript(expr, lookup, p));
 
         contexts.put(AggregationScript.CONTEXT,
-            (Expression expr) -> (AggregationScript.Factory) (p, lookup) -> newAggregationScript(expr, lookup, p));
+            (Expression expr) -> new AggregationScript.Factory() {
+                @Override
+                public AggregationScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup) {
+                    return newAggregationScript(expr, lookup, params);
+                }
+
+                @Override
+                public boolean isResultDeterministic() {
+                    return true;
+                }
+            });
 
         contexts.put(NumberSortScript.CONTEXT,
-            (Expression expr) -> (NumberSortScript.Factory) (p, lookup) -> newSortScript(expr, lookup, p));
+            (Expression expr) -> new NumberSortScript.Factory() {
+                @Override
+                public NumberSortScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup) {
+                    return newSortScript(expr, lookup, params);
+                }
+
+                @Override
+                public boolean isResultDeterministic() {
+                    return true;
+                }
+            });
 
         contexts.put(FieldScript.CONTEXT,
-            (Expression expr) -> (FieldScript.Factory) (p, lookup) -> newFieldScript(expr, lookup, p));
+            (Expression expr) -> new FieldScript.Factory() {
+                @Override
+                public FieldScript.LeafFactory newFactory(Map<String, Object> params, SearchLookup lookup) {
+                    return newFieldScript(expr, lookup, params);
+                }
 
-        ExpressionScriptEngine.contexts = Collections.unmodifiableMap(contexts);
-    }
+                @Override
+                public boolean isResultDeterministic() {
+                    return true;
+                }
+            });
+
+            ExpressionScriptEngine.contexts = Collections.unmodifiableMap(contexts);
+        }
 
     @Override
     public String getType() {
         return NAME;
     }
 
     @Override
-    public <T extends ScriptFactory> T compile(
+    public <T> T compile(
         String scriptName,
         String scriptSource,
         ScriptContext<T> context,

modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/MustacheScriptEngine.java

@@ -21,9 +21,8 @@
 import com.github.mustachejava.Mustache;
 import com.github.mustachejava.MustacheException;
 import com.github.mustachejava.MustacheFactory;
-
-import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.logging.log4j.util.Supplier;
 import org.elasticsearch.SpecialPermission;
@@ -32,7 +31,6 @@
 import org.elasticsearch.script.ScriptContext;
 import org.elasticsearch.script.ScriptEngine;
 import org.elasticsearch.script.ScriptException;
-import org.elasticsearch.script.ScriptFactory;
 import org.elasticsearch.script.TemplateScript;
 
 import java.io.Reader;
@@ -65,7 +63,7 @@ public final class MustacheScriptEngine implements ScriptEngine {
      * @return a compiled template object for later execution.
      * */
     @Override
-    public <T extends ScriptFactory> T compile(
+    public <T> T compile(
         String templateName,
         String templateSource,
         ScriptContext<T> context,

modules/lang-painless/src/main/java/org/elasticsearch/painless/PainlessScriptEngine.java

@@ -28,7 +28,6 @@
 import org.elasticsearch.script.ScriptContext;
 import org.elasticsearch.script.ScriptEngine;
 import org.elasticsearch.script.ScriptException;
-import org.elasticsearch.script.ScriptFactory;
 import org.objectweb.asm.ClassWriter;
 import org.objectweb.asm.Opcodes;
 import org.objectweb.asm.Type;
@@ -123,7 +122,7 @@ public String getType() {
     }
 
     @Override
-    public <T extends ScriptFactory> T compile(
+    public <T> T compile(
         String scriptName,
         String scriptSource,
         ScriptContext<T> context,
@@ -169,7 +168,7 @@ public Set<ScriptContext<?>> getSupportedContexts() {
      * @param <T> The factory class.
      * @return A factory class that will return script instances.
      */
-    private <T extends ScriptFactory> Type generateStatefulFactory(
+    private <T> Type generateStatefulFactory(
         Loader loader,
         ScriptContext<T> context,
         Set<String> extractedVariables
@@ -275,7 +274,7 @@ private <T extends ScriptFactory> Type generateStatefulFactory(
      * @param <T> The factory class.
      * @return A factory class that will return script instances.
      */
-    private <T extends ScriptFactory> T generateFactory(
+    private <T> T generateFactory(
         Loader loader,
         ScriptContext<T> context,
         Set<String> extractedVariables,

modules/lang-painless/src/main/java/org/elasticsearch/painless/action/PainlessExecuteAction.java

@@ -76,7 +76,6 @@
 import org.elasticsearch.script.ScoreScript;
 import org.elasticsearch.script.Script;
 import org.elasticsearch.script.ScriptContext;
-import org.elasticsearch.script.ScriptFactory;
 import org.elasticsearch.script.ScriptService;
 import org.elasticsearch.script.ScriptType;
 import org.elasticsearch.threadpool.ThreadPool;
@@ -435,7 +434,7 @@ public Map<String, Object> getParams() {
 
         public abstract Object execute();
 
-        public interface Factory extends ScriptFactory {
+        public interface Factory {
 
             PainlessTestScript newInstance(Map<String, Object> params);