Remove remaining `index.mapper.single_type` setting usage from tests (#25388)

This change removes the remaining explicitly specified `index.mapper.single_type`
settings from tests in order to allow the removal of the setting.
This is the already approved part of #25375 broken out to simplfiy reviews on

10 files changed, 343 insertions, 136 deletions

diff --git a/core/src/test/java/org/elasticsearch/index/fielddata/AbstractFieldDataTestCase.java b/core/src/test/java/org/elasticsearch/index/fielddata/AbstractFieldDataTestCase.java
index 99aa081608..b9e3a0813b 100644
--- a/core/src/test/java/org/elasticsearch/index/fielddata/AbstractFieldDataTestCase.java
+++ b/core/src/test/java/org/elasticsearch/index/fielddata/AbstractFieldDataTestCase.java
@@ -134,7 +134,7 @@ public abstract class AbstractFieldDataTestCase extends ESSingleNodeTestCase {
 
     @Before
     public void setup() throws Exception {
-        indexService = createIndex("test", Settings.builder().put("mapping.single_type", false).build());
+        indexService = createIndex("test", Settings.builder().build());
         mapperService = indexService.mapperService();
         indicesFieldDataCache = getInstanceFromNode(IndicesService.class).getIndicesFieldDataCache();
         ifdService = indexService.fieldData();
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java b/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java
index daf3d99ad5..06c31f4dd1 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/DynamicMappingTests.java
@@ -36,9 +36,13 @@ import org.elasticsearch.index.mapper.BooleanFieldMapper.BooleanFieldType;
 import org.elasticsearch.index.mapper.DateFieldMapper.DateFieldType;
 import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.index.mapper.NumberFieldMapper.NumberFieldType;
+import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESSingleNodeTestCase;
+import org.elasticsearch.test.InternalSettingsPlugin;
 
 import java.io.IOException;
+import java.util.Collection;
+import java.util.Collections;
 
 import static java.util.Collections.emptyMap;
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
@@ -49,6 +53,11 @@ import static org.hamcrest.Matchers.nullValue;
 
 public class DynamicMappingTests extends ESSingleNodeTestCase {
 
+    @Override
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return Collections.singleton(InternalSettingsPlugin.class);
+    }
+
     public void testDynamicTrue() throws IOException {
         String mapping = jsonBuilder().startObject().startObject("type")
                 .field("dynamic", "true")
@@ -183,9 +192,7 @@ public class DynamicMappingTests extends ESSingleNodeTestCase {
         XContentBuilder mapping = jsonBuilder().startObject().startObject("_default_")
                 .field("dynamic", "strict")
                 .endObject().endObject();
-
-        IndexService indexService = createIndex("test", Settings.EMPTY, "_default_", mapping);
-
+        createIndex("test", Settings.EMPTY, "_default_", mapping);
         try {
             client().prepareIndex().setIndex("test").setType("type").setSource(jsonBuilder().startObject().field("test", "test").endObject()).get();
             fail();
@@ -525,9 +532,9 @@ public class DynamicMappingTests extends ESSingleNodeTestCase {
     }
 
     public void testMixTemplateMultiFieldAndMappingReuse() throws Exception {
-        IndexService indexService = createIndex("test", Settings.builder().put("mapping.single_type", false).build());
+        IndexService indexService = createIndex("test");
         XContentBuilder mappings1 = jsonBuilder().startObject()
-                .startObject("type1")
+                .startObject("doc")
                     .startArray("dynamic_templates")
                         .startObject()
                             .startObject("template1")
@@ -544,20 +551,60 @@ public class DynamicMappingTests extends ESSingleNodeTestCase {
                         .endObject()
                     .endArray()
                 .endObject().endObject();
+        indexService.mapperService().merge("doc", new CompressedXContent(mappings1.bytes()),
+            MapperService.MergeReason.MAPPING_UPDATE, false);
+
+        XContentBuilder json = XContentFactory.jsonBuilder().startObject()
+                    .field("field", "foo")
+                .endObject();
+        SourceToParse source = SourceToParse.source("test", "doc", "1", json.bytes(), json.contentType());
+        DocumentMapper mapper = indexService.mapperService().documentMapper("doc");
+        assertNull(mapper.mappers().getMapper("field.raw"));
+        ParsedDocument parsed = mapper.parse(source);
+        assertNotNull(parsed.dynamicMappingsUpdate());
+
+        indexService.mapperService().merge("doc", new CompressedXContent(parsed.dynamicMappingsUpdate().toString()),
+            MapperService.MergeReason.MAPPING_UPDATE, false);
+        mapper = indexService.mapperService().documentMapper("doc");
+        assertNotNull(mapper.mappers().getMapper("field.raw"));
+        parsed = mapper.parse(source);
+        assertNull(parsed.dynamicMappingsUpdate());
+    }
+
+    public void testMixTemplateMultiFieldMultiTypeAndMappingReuse() throws Exception {
+        IndexService indexService = createIndex("test", Settings.builder().put("index.version.created", Version.V_5_6_0).build());
+        XContentBuilder mappings1 = jsonBuilder().startObject()
+            .startObject("type1")
+            .startArray("dynamic_templates")
+            .startObject()
+            .startObject("template1")
+            .field("match_mapping_type", "string")
+            .startObject("mapping")
+            .field("type", "text")
+            .startObject("fields")
+            .startObject("raw")
+            .field("type", "keyword")
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endObject()
+            .endArray()
+            .endObject().endObject();
         indexService.mapperService().merge("type1", new CompressedXContent(mappings1.bytes()), MapperService.MergeReason.MAPPING_UPDATE, false);
         XContentBuilder mappings2 = jsonBuilder().startObject()
-                .startObject("type2")
-                    .startObject("properties")
-                        .startObject("field")
-                            .field("type", "text")
-                        .endObject()
-                    .endObject()
-                .endObject().endObject();
+            .startObject("type2")
+            .startObject("properties")
+            .startObject("field")
+            .field("type", "text")
+            .endObject()
+            .endObject()
+            .endObject().endObject();
         indexService.mapperService().merge("type2", new CompressedXContent(mappings2.bytes()), MapperService.MergeReason.MAPPING_UPDATE, false);
 
         XContentBuilder json = XContentFactory.jsonBuilder().startObject()
-                    .field("field", "foo")
-                .endObject();
+            .field("field", "foo")
+            .endObject();
         SourceToParse source = SourceToParse.source("test", "type1", "1", json.bytes(), json.contentType());
         DocumentMapper mapper = indexService.mapperService().documentMapper("type1");
         assertNull(mapper.mappers().getMapper("field.raw"));
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/NestedObjectMapperTests.java b/core/src/test/java/org/elasticsearch/index/mapper/NestedObjectMapperTests.java
index f4a8ce11c5..157033d414 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/NestedObjectMapperTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/NestedObjectMapperTests.java
@@ -19,16 +19,21 @@
 
 package org.elasticsearch.index.mapper;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.common.xcontent.XContentType;
 import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.index.mapper.ObjectMapper.Dynamic;
+import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESSingleNodeTestCase;
+import org.elasticsearch.test.InternalSettingsPlugin;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
+import java.util.Collection;
+import java.util.Collections;
 import java.util.function.Function;
 
 import static org.hamcrest.Matchers.containsString;
@@ -36,6 +41,12 @@ import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.nullValue;
 
 public class NestedObjectMapperTests extends ESSingleNodeTestCase {
+
+    @Override
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return Collections.singleton(InternalSettingsPlugin.class);
+    }
+
     public void testEmptyNested() throws Exception {
         String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").startObject("properties")
                 .startObject("nested1").field("type", "nested").endObject()
@@ -382,16 +393,34 @@ public class NestedObjectMapperTests extends ESSingleNodeTestCase {
                 .mapperService().merge("type", new CompressedXContent(mapping.apply("type")), MergeReason.MAPPING_UPDATE, false));
         assertThat(e.getMessage(), containsString("Limit of nested fields [1] in index [test3] has been exceeded"));
 
+        // do not check nested fields limit if mapping is not updated
+        createIndex("test4", Settings.builder().put(MapperService.INDEX_MAPPING_NESTED_FIELDS_LIMIT_SETTING.getKey(), 0).build())
+            .mapperService().merge("type", new CompressedXContent(mapping.apply("type")), MergeReason.MAPPING_RECOVERY, false);
+    }
+
+    public void testLimitOfNestedFieldsWithMultiTypePerIndex() throws Exception {
+        Function<String, String> mapping = type -> {
+            try {
+                return XContentFactory.jsonBuilder().startObject().startObject(type).startObject("properties")
+                    .startObject("nested1").field("type", "nested").startObject("properties")
+                    .startObject("nested2").field("type", "nested")
+                    .endObject().endObject().endObject()
+                    .endObject().endObject().endObject().string();
+            } catch (IOException e) {
+                throw new UncheckedIOException(e);
+            }
+        };
+
         MapperService mapperService = createIndex("test4", Settings.builder()
-                .put("mapping.single_type", false)
-                .put(MapperService.INDEX_MAPPING_NESTED_FIELDS_LIMIT_SETTING.getKey(), 2).build()).mapperService();
+            .put("index.version.created", Version.V_5_6_0)
+            .put(MapperService.INDEX_MAPPING_NESTED_FIELDS_LIMIT_SETTING.getKey(), 2).build()).mapperService();
         mapperService.merge("type1", new CompressedXContent(mapping.apply("type1")), MergeReason.MAPPING_UPDATE, false);
         // merging same fields, but different type is ok
         mapperService.merge("type2", new CompressedXContent(mapping.apply("type2")), MergeReason.MAPPING_UPDATE, false);
         // adding new fields from different type is not ok
         String mapping2 = XContentFactory.jsonBuilder().startObject().startObject("type3").startObject("properties").startObject("nested3")
             .field("type", "nested").startObject("properties").endObject().endObject().endObject().endObject().endObject().string();
-        e = expectThrows(IllegalArgumentException.class, () ->
+        IllegalArgumentException e = expectThrows(IllegalArgumentException.class, () ->
             mapperService.merge("type3", new CompressedXContent(mapping2), MergeReason.MAPPING_UPDATE, false));
         assertThat(e.getMessage(), containsString("Limit of nested fields [2] in index [test4] has been exceeded"));
 
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/ParentFieldMapperTests.java b/core/src/test/java/org/elasticsearch/index/mapper/ParentFieldMapperTests.java
index 7ef1b751ee..935562a2bc 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/ParentFieldMapperTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/ParentFieldMapperTests.java
@@ -20,6 +20,7 @@ package org.elasticsearch.index.mapper;
 
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.index.IndexableField;
+import org.elasticsearch.Version;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
@@ -35,9 +36,12 @@ import org.elasticsearch.index.analysis.NamedAnalyzer;
 import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.index.similarity.SimilarityService;
 import org.elasticsearch.indices.IndicesModule;
+import org.elasticsearch.plugins.Plugin;
 import org.elasticsearch.test.ESSingleNodeTestCase;
 import org.elasticsearch.test.IndexSettingsModule;
+import org.elasticsearch.test.InternalSettingsPlugin;
 
+import java.util.Collection;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
@@ -47,6 +51,11 @@ import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 
 public class ParentFieldMapperTests extends ESSingleNodeTestCase {
 
+    @Override
+    protected Collection<Class<? extends Plugin>> getPlugins() {
+        return Collections.singleton(InternalSettingsPlugin.class);
+    }
+
     public void testParentSetInDocNotAllowed() throws Exception {
         String mapping = XContentFactory.jsonBuilder().startObject().startObject("type")
                 .endObject().endObject().string();
@@ -67,7 +76,7 @@ public class ParentFieldMapperTests extends ESSingleNodeTestCase {
         String childMapping = XContentFactory.jsonBuilder().startObject().startObject("child_type")
                 .startObject("_parent").field("type", "parent_type").endObject()
                 .endObject().endObject().string();
-        IndexService indexService = createIndex("test", Settings.builder().put("mapping.single_type", false).build());
+        IndexService indexService = createIndex("test", Settings.builder().put("index.version.created", Version.V_5_6_0).build());
         indexService.mapperService().merge("parent_type", new CompressedXContent(parentMapping), MergeReason.MAPPING_UPDATE, false);
         indexService.mapperService().merge("child_type", new CompressedXContent(childMapping), MergeReason.MAPPING_UPDATE, false);
 
diff --git a/core/src/test/java/org/elasticsearch/index/mapper/UpdateMappingTests.java b/core/src/test/java/org/elasticsearch/index/mapper/UpdateMappingTests.java
index 7c18d9cb1a..c6a1eae036 100644
--- a/core/src/test/java/org/elasticsearch/index/mapper/UpdateMappingTests.java
+++ b/core/src/test/java/org/elasticsearch/index/mapper/UpdateMappingTests.java
@@ -19,6 +19,7 @@
 
 package org.elasticsearch.index.mapper;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
@@ -150,7 +151,8 @@ public class UpdateMappingTests extends ESSingleNodeTestCase {
                 .startObject("properties").startObject("foo").field("type", "long").endObject()
                 .endObject().endObject().endObject();
         XContentBuilder mapping2 = XContentFactory.jsonBuilder().startObject().startObject("type2").endObject().endObject();
-        MapperService mapperService = createIndex("test", Settings.builder().put("mapping.single_type", false).build()).mapperService();
+        MapperService mapperService = createIndex("test", Settings.builder().put("index.version.created",
+            Version.V_5_6_0).build()).mapperService();
 
         mapperService.merge("type1", new CompressedXContent(mapping1.string()), MapperService.MergeReason.MAPPING_UPDATE, false);
         mapperService.merge("type2", new CompressedXContent(mapping2.string()), MapperService.MergeReason.MAPPING_UPDATE, false);
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.exists_type/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.exists_type/10_basic.yml
index fb56ab4e4d..278fd1ca8e 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.exists_type/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.exists_type/10_basic.yml
@@ -2,14 +2,12 @@
 "Exists type":
  - skip:
     version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
+    reason:  multiple types are not supported on 6.x indices onwards
 
  - do:
      indices.create:
        index: test_1
        body:
-         settings:
-           mapping.single_type: false
          mappings:
            type_1: {}
            type_2: {}
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/10_basic.yml
index b17f2512b6..90bb2747a7 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/10_basic.yml
@@ -4,21 +4,14 @@ setup:
         indices.create:
           index: test_1
           body:
-              settings:
-                mapping.single_type: false
               mappings:
-                type_1: {}
-                type_2: {}
+                doc: {}
   - do:
         indices.create:
           index: test_2
           body:
-              settings:
-                mapping.single_type: false
               mappings:
-                type_2: {}
-                type_3: {}
-
+                doc: {}
 ---
 "Get /{index}/_mapping with empty mappings":
 
@@ -35,191 +28,117 @@ setup:
 ---
 "Get /_mapping":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping: {}
 
- - is_true: test_1.mappings.type_1
- - is_true: test_1.mappings.type_2
- - is_true: test_2.mappings.type_2
- - is_true: test_2.mappings.type_3
+ - is_true: test_1.mappings.doc
+ - is_true: test_2.mappings.doc
 
 ---
 "Get /{index}/_mapping":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: test_1
 
- - is_true: test_1.mappings.type_1
- - is_true: test_1.mappings.type_2
+ - is_true: test_1.mappings.doc
  - is_false: test_2
 
 
 ---
 "Get /{index}/_mapping/_all":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: test_1
         type:  _all
 
- - is_true: test_1.mappings.type_1
- - is_true: test_1.mappings.type_2
+ - is_true: test_1.mappings.doc
  - is_false: test_2
 
 ---
 "Get /{index}/_mapping/*":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: test_1
         type:  '*'
 
- - is_true: test_1.mappings.type_1
- - is_true: test_1.mappings.type_2
+ - is_true: test_1.mappings.doc
  - is_false: test_2
 
 ---
 "Get /{index}/_mapping/{type}":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: test_1
-        type:  type_1
+        type:  doc
 
- - is_false: test_1.mappings.type_2
- - is_false: test_2
-
----
-"Get /{index}/_mapping/{type,type}":
-
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
- - do:
-    indices.get_mapping:
-        index: test_1
-        type:  type_1,type_2
-
- - is_true: test_1.mappings.type_1
- - is_true: test_1.mappings.type_2
+ - is_true: test_1.mappings.doc
  - is_false: test_2
 
 ---
 "Get /{index}/_mapping/{type*}":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: test_1
-        type:  '*2'
+        type:  'd*'
 
- - is_true: test_1.mappings.type_2
- - is_false: test_1.mappings.type_1
+ - is_true: test_1.mappings.doc
  - is_false: test_2
 
 ---
 "Get /_mapping/{type}":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
-        type: type_2
+        type: doc
 
- - is_true: test_1.mappings.type_2
- - is_true: test_2.mappings.type_2
- - is_false: test_1.mappings.type_1
- - is_false: test_2.mappings.type_3
+ - is_true: test_1.mappings.doc
+ - is_true: test_2.mappings.doc
 
 ---
 "Get /_all/_mapping/{type}":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: _all
-        type: type_2
+        type: doc
 
- - is_true: test_1.mappings.type_2
- - is_true: test_2.mappings.type_2
- - is_false: test_1.mappings.type_1
- - is_false: test_2.mappings.type_3
+ - is_true: test_1.mappings.doc
+ - is_true: test_2.mappings.doc
 
 ---
 "Get /*/_mapping/{type}":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: '*'
-        type: type_2
+        type: doc
 
- - is_true: test_1.mappings.type_2
- - is_true: test_2.mappings.type_2
- - is_false: test_1.mappings.type_1
- - is_false: test_2.mappings.type_3
+ - is_true: test_1.mappings.doc
+ - is_true: test_2.mappings.doc
 
 ---
 "Get /index,index/_mapping/{type}":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: test_1,test_2
-        type: type_2
+        type: doc
 
- - is_true: test_1.mappings.type_2
- - is_true: test_2.mappings.type_2
- - is_false: test_2.mappings.type_3
+ - is_true: test_1.mappings.doc
+ - is_true: test_2.mappings.doc
 
 ---
 "Get /index*/_mapping/{type}":
 
- - skip:
-    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-    reason:  mapping.single_type can not be changed on 6.x indices onwards
-
  - do:
     indices.get_mapping:
         index: '*2'
-        type: type_2
+        type: doc
 
- - is_true: test_2.mappings.type_2
+ - is_true: test_2.mappings.doc
  - is_false: test_1
- - is_false: test_2.mappings.type_3
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/70_legacy_multi_type.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/70_legacy_multi_type.yml
new file mode 100644
index 0000000000..9b36ac1535
--- /dev/null
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/70_legacy_multi_type.yml
@@ -0,0 +1,208 @@
+---
+setup:
+  - do:
+        indices.create:
+          index: test_1
+          body:
+              mappings:
+                type_1: {}
+                type_2: {}
+  - do:
+        indices.create:
+          index: test_2
+          body:
+              mappings:
+                type_2: {}
+                type_3: {}
+
+---
+"Get /_mapping":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping: {}
+
+ - is_true: test_1.mappings.type_1
+ - is_true: test_1.mappings.type_2
+ - is_true: test_2.mappings.type_2
+ - is_true: test_2.mappings.type_3
+
+---
+"Get /{index}/_mapping":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: test_1
+
+ - is_true: test_1.mappings.type_1
+ - is_true: test_1.mappings.type_2
+ - is_false: test_2
+
+
+---
+"Get /{index}/_mapping/_all":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: test_1
+        type:  _all
+
+ - is_true: test_1.mappings.type_1
+ - is_true: test_1.mappings.type_2
+ - is_false: test_2
+
+---
+"Get /{index}/_mapping/*":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: test_1
+        type:  '*'
+
+ - is_true: test_1.mappings.type_1
+ - is_true: test_1.mappings.type_2
+ - is_false: test_2
+
+---
+"Get /{index}/_mapping/{type}":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: test_1
+        type:  type_1
+
+ - is_false: test_1.mappings.type_2
+ - is_false: test_2
+
+---
+"Get /{index}/_mapping/{type,type}":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: test_1
+        type:  type_1,type_2
+
+ - is_true: test_1.mappings.type_1
+ - is_true: test_1.mappings.type_2
+ - is_false: test_2
+
+---
+"Get /{index}/_mapping/{type*}":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: test_1
+        type:  '*2'
+
+ - is_true: test_1.mappings.type_2
+ - is_false: test_1.mappings.type_1
+ - is_false: test_2
+
+---
+"Get /_mapping/{type}":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        type: type_2
+
+ - is_true: test_1.mappings.type_2
+ - is_true: test_2.mappings.type_2
+ - is_false: test_1.mappings.type_1
+ - is_false: test_2.mappings.type_3
+
+---
+"Get /_all/_mapping/{type}":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: _all
+        type: type_2
+
+ - is_true: test_1.mappings.type_2
+ - is_true: test_2.mappings.type_2
+ - is_false: test_1.mappings.type_1
+ - is_false: test_2.mappings.type_3
+
+---
+"Get /*/_mapping/{type}":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: '*'
+        type: type_2
+
+ - is_true: test_1.mappings.type_2
+ - is_true: test_2.mappings.type_2
+ - is_false: test_1.mappings.type_1
+ - is_false: test_2.mappings.type_3
+
+---
+"Get /index,index/_mapping/{type}":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: test_1,test_2
+        type: type_2
+
+ - is_true: test_1.mappings.type_2
+ - is_true: test_2.mappings.type_2
+ - is_false: test_2.mappings.type_3
+
+---
+"Get /index*/_mapping/{type}":
+
+ - skip:
+    version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
+    reason:  multiple types are not supported on 6.x indices onwards
+
+ - do:
+    indices.get_mapping:
+        index: '*2'
+        type: type_2
+
+ - is_true: test_2.mappings.type_2
+ - is_false: test_1
+ - is_false: test_2.mappings.type_3
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/mget/15_ids.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/mget/15_ids.yml
index 7827965ec6..1dd851554b 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/mget/15_ids.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/mget/15_ids.yml
@@ -2,14 +2,11 @@
 "IDs":
   - skip:
         version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-        reason:  mapping.single_type can not be changed on 6.x indices onwards
+        reason:  multiple types are not supported on 6.x indices onwards
 
   - do:
         indices.create:
           index: test_1
-          body:
-              settings:
-                mapping.single_type: false
 
   - do:
       index:
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/search.inner_hits/10_basic.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/search.inner_hits/10_basic.yml
index 3c2eba90e6..e90fda9fe0 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/search.inner_hits/10_basic.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/search.inner_hits/10_basic.yml
@@ -4,8 +4,6 @@ setup:
       indices.create:
         index: test
         body:
-            settings:
-              mapping.single_type: false
             mappings:
               type_1:
                 properties:
@@ -16,7 +14,7 @@ setup:
 "Nested inner hits":
     - skip:
         version: "5.99.99 - "# this will only run in a mixed cluster environment with at least 1 5.x node
-        reason:  mapping.single_type can not be changed on 6.x indices onwards
+        reason:  multiple types are not supported on 6.x indices onwards
     - do:
         index:
           index: test