Deprecate accepting malformed requests in stored script API (#28939)

The stored scripts API today accepts malformed requests instead of throwing an exception.
This PR deprecates accepting malformed put stored script requests (requests not using the official script format).

Relates to #27612

modules/lang-mustache/src/test/java/org/elasticsearch/script/mustache/SearchTemplateIT.java

@@ -198,6 +198,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
 
         getResponse = client().admin().cluster().prepareGetStoredScript("testTemplate").get();
         assertNull(getResponse.getSource());
+        assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
     }
 
     public void testIndexedTemplate() throws Exception {
@@ -267,6 +268,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                 .setScript("2").setScriptType(ScriptType.STORED).setScriptParams(templateParams)
                 .get();
         assertHitCount(searchResponse.getResponse(), 1);
+        assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
     }
 
     // Relates to #10397
@@ -311,6 +313,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                     .get();
             assertHitCount(searchResponse.getResponse(), 1);
         }
+        assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
     }
 
     public void testIndexedTemplateWithArray() throws Exception {
@@ -339,6 +342,7 @@ public class SearchTemplateIT extends ESSingleNodeTestCase {
                 .setScript("4").setScriptType(ScriptType.STORED).setScriptParams(arrayTemplateParams)
                 .get();
         assertHitCount(searchResponse.getResponse(), 5);
+        assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
     }
 
 }

server/src/main/java/org/elasticsearch/script/StoredScriptSource.java

@@ -74,6 +74,11 @@ public class StoredScriptSource extends AbstractDiffable<StoredScriptSource> imp
      */
     public static final ParseField TEMPLATE_PARSE_FIELD = new ParseField("template");
 
+    /**
+     * Standard {@link ParseField} for query on the inner field.
+     */
+    public static final ParseField TEMPLATE_NO_WRAPPER_PARSE_FIELD = new ParseField("query");
+
     /**
      * Standard {@link ParseField} for lang on the inner level.
      */
@@ -189,6 +194,26 @@ public class StoredScriptSource extends AbstractDiffable<StoredScriptSource> imp
         PARSER.declareField(Builder::setOptions, XContentParser::mapStrings, OPTIONS_PARSE_FIELD, ValueType.OBJECT);
     }
 
+    private static StoredScriptSource parseRemaining(Token token, XContentParser parser) throws IOException {
+        try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
+            if (token != Token.START_OBJECT) {
+                builder.startObject();
+                builder.copyCurrentStructure(parser);
+                builder.endObject();
+            } else {
+                builder.copyCurrentStructure(parser);
+            }
+
+            String source = Strings.toString(builder);
+
+            if (source == null || source.isEmpty()) {
+                DEPRECATION_LOGGER.deprecated("empty templates should no longer be used");
+            }
+
+            return new StoredScriptSource(Script.DEFAULT_TEMPLATE_LANG, source, Collections.emptyMap());
+        }
+    }
+
     /**
      * This will parse XContent into a {@link StoredScriptSource}.  The following formats can be parsed:
      *
@@ -304,10 +329,11 @@ public class StoredScriptSource extends AbstractDiffable<StoredScriptSource> imp
                 } else {
                     throw new ParsingException(parser.getTokenLocation(), "unexpected token [" + token + "], expected [{, <source>]");
                 }
-            } else {
+            } else if (TEMPLATE_PARSE_FIELD.getPreferredName().equals(name)) {
-                if (TEMPLATE_PARSE_FIELD.getPreferredName().equals(name)) {
-                    token = parser.nextToken();
 
+                DEPRECATION_LOGGER.deprecated("the template context is now deprecated. Specify templates in a \"script\" element.");
+
+                token = parser.nextToken();
                 if (token == Token.VALUE_STRING) {
                     String source = parser.text();
 
@@ -316,26 +342,15 @@ public class StoredScriptSource extends AbstractDiffable<StoredScriptSource> imp
                     }
 
                     return new StoredScriptSource(Script.DEFAULT_TEMPLATE_LANG, source, Collections.emptyMap());
-                    }
-                }
-
-                try (XContentBuilder builder = XContentFactory.jsonBuilder()) {
-                    if (token != Token.START_OBJECT) {
-                        builder.startObject();
-                        builder.copyCurrentStructure(parser);
-                        builder.endObject();
                 } else {
-                        builder.copyCurrentStructure(parser);
+                    return parseRemaining(token, parser);
-                    }
-
-                    String source = Strings.toString(builder);
-
-                    if (source == null || source.isEmpty()) {
-                        DEPRECATION_LOGGER.deprecated("empty templates should no longer be used");
-                    }
-
-                    return new StoredScriptSource(Script.DEFAULT_TEMPLATE_LANG, source, Collections.emptyMap());
                 }
+            } else if (TEMPLATE_NO_WRAPPER_PARSE_FIELD.getPreferredName().equals(name)) {
+                DEPRECATION_LOGGER.deprecated("the template context is now deprecated. Specify templates in a \"script\" element.");
+                return parseRemaining(token, parser);
+            } else {
+                DEPRECATION_LOGGER.deprecated("scripts should not be stored without a context. Specify them in a \"script\" element.");
+                return parseRemaining(token, parser);
             }
         } catch (IOException ioe) {
             throw new UncheckedIOException(ioe);

server/src/test/java/org/elasticsearch/script/ScriptMetaDataTests.java

@@ -81,10 +81,12 @@ public class ScriptMetaDataTests extends AbstractSerializingTestCase<ScriptMetaD
         XContentBuilder sourceBuilder = XContentFactory.jsonBuilder();
         sourceBuilder.startObject().startObject("template").field("field", "value").endObject().endObject();
         builder.storeScript("template", StoredScriptSource.parse(BytesReference.bytes(sourceBuilder), sourceBuilder.contentType()));
+        assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
 
         sourceBuilder = XContentFactory.jsonBuilder();
         sourceBuilder.startObject().field("template", "value").endObject();
         builder.storeScript("template_field", StoredScriptSource.parse(BytesReference.bytes(sourceBuilder), sourceBuilder.contentType()));
+        assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
 
         sourceBuilder = XContentFactory.jsonBuilder();
         sourceBuilder.startObject().startObject("script").field("lang", "_lang").field("source", "_source").endObject().endObject();
@@ -99,14 +101,19 @@ public class ScriptMetaDataTests extends AbstractSerializingTestCase<ScriptMetaD
     public void testDiff() throws Exception {
         ScriptMetaData.Builder builder = new ScriptMetaData.Builder(null);
         builder.storeScript("1", StoredScriptSource.parse(new BytesArray("{\"foo\":\"abc\"}"), XContentType.JSON));
+        assertWarnings("scripts should not be stored without a context. Specify them in a \"script\" element.");
         builder.storeScript("2", StoredScriptSource.parse(new BytesArray("{\"foo\":\"def\"}"), XContentType.JSON));
+        assertWarnings("scripts should not be stored without a context. Specify them in a \"script\" element.");
         builder.storeScript("3", StoredScriptSource.parse(new BytesArray("{\"foo\":\"ghi\"}"), XContentType.JSON));
+        assertWarnings("scripts should not be stored without a context. Specify them in a \"script\" element.");
         ScriptMetaData scriptMetaData1 = builder.build();
 
         builder = new ScriptMetaData.Builder(scriptMetaData1);
         builder.storeScript("2", StoredScriptSource.parse(new BytesArray("{\"foo\":\"changed\"}"), XContentType.JSON));
+        assertWarnings("scripts should not be stored without a context. Specify them in a \"script\" element.");
         builder.deleteScript("3");
         builder.storeScript("4", StoredScriptSource.parse(new BytesArray("{\"foo\":\"jkl\"}"), XContentType.JSON));
+        assertWarnings("scripts should not be stored without a context. Specify them in a \"script\" element.");
         ScriptMetaData scriptMetaData2 = builder.build();
 
         ScriptMetaData.ScriptMetadataDiff diff = (ScriptMetaData.ScriptMetadataDiff) scriptMetaData2.diff(scriptMetaData1);

server/src/test/java/org/elasticsearch/script/StoredScriptSourceTests.java

@@ -50,7 +50,9 @@ public class StoredScriptSourceTests extends AbstractSerializingTestCase<StoredS
             if (randomBoolean()) {
                 options.put(Script.CONTENT_TYPE_OPTION, xContentType.mediaType());
             }
-            return StoredScriptSource.parse(BytesReference.bytes(template), xContentType);
+            StoredScriptSource source = StoredScriptSource.parse(BytesReference.bytes(template), xContentType);
+            assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
+            return source;
         } catch (IOException e) {
             throw new AssertionError("Failed to create test instance", e);
         }

server/src/test/java/org/elasticsearch/script/StoredScriptTests.java

@@ -74,6 +74,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
             StoredScriptSource source = new StoredScriptSource("mustache", "code", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
+            assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
         }
 
         // complex template with wrapper template object
@@ -89,6 +90,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
             StoredScriptSource source = new StoredScriptSource("mustache", code, Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
+            assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
         }
 
         // complex template with no wrapper object
@@ -104,6 +106,7 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
             StoredScriptSource source = new StoredScriptSource("mustache", code, Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
+            assertWarnings("the template context is now deprecated. Specify templates in a \"script\" element.");
         }
 
         // complex template using script as the field name
@@ -223,7 +226,10 @@ public class StoredScriptTests extends AbstractSerializingTestCase<StoredScriptS
             StoredScriptSource source = new StoredScriptSource(Script.DEFAULT_TEMPLATE_LANG, "", Collections.emptyMap());
 
             assertThat(parsed, equalTo(source));
-            assertWarnings("empty templates should no longer be used");
+            assertWarnings(
+                "the template context is now deprecated. Specify templates in a \"script\" element.",
+                "empty templates should no longer be used"
+            );
         }
 
         try (XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON)) {