Adding a deprecation info api check for custom types in templates

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/ClusterDeprecationChecks.java

@@ -22,6 +22,7 @@
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.mapper.FieldNamesFieldMapper;
 import org.elasticsearch.index.mapper.GeoShapeFieldMapper;
+import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.ingest.IngestService;
 import org.elasticsearch.ingest.PipelineConfiguration;
 import org.elasticsearch.xcontent.XContentType;
@@ -37,6 +38,7 @@
 import java.util.Map;
 import java.util.Objects;
 import java.util.Set;
+import java.util.TreeSet;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.stream.Collectors;
 import java.util.stream.StreamSupport;
@@ -210,28 +212,56 @@ static DeprecationIssue checkPollIntervalTooLow(ClusterState state) {
         return null;
     }
 
-    static DeprecationIssue checkTemplatesWithMultipleTypes(ClusterState state) {
-        Set<String> templatesWithMultipleTypes = new HashSet<>();
+    static DeprecationIssue checkTemplatesWithCustomAndMultipleTypes(ClusterState state) {
+        Set<String> templatesWithMultipleTypes = new TreeSet<>();
+        Set<String> templatesWithCustomTypes = new TreeSet<>();
         state.getMetadata().getTemplates().forEach((templateCursor) -> {
             String templateName = templateCursor.key;
             ImmutableOpenMap<String, CompressedXContent> mappings = templateCursor.value.mappings();
-            if (mappings != null && mappings.size() > 1) {
-                templatesWithMultipleTypes.add(templateName);
+            if (mappings != null) {
+                if (mappings.size() > 1) {
+                    templatesWithMultipleTypes.add(templateName);
+                }
+                boolean hasCustomType = mappings.stream().anyMatch(mapping -> {
+                    String typeName = mapping.getKey();
+                    return MapperService.SINGLE_MAPPING_NAME.equals(typeName) == false;
+                });
+                if (hasCustomType) {
+                    templatesWithCustomTypes.add(templateName);
+                }
             }
         });
-        if (templatesWithMultipleTypes.isEmpty()) {
-            return null;
+        final DeprecationIssue deprecationIssue;
+        if (templatesWithMultipleTypes.isEmpty() && templatesWithCustomTypes.isEmpty()) {
+            deprecationIssue = null;
+        } else if (templatesWithMultipleTypes.isEmpty()) {
+            deprecationIssue = new DeprecationIssue(
+                DeprecationIssue.Level.CRITICAL,
+                "Custom mapping types in index templates are deprecated",
+                "https://ela.st/es-deprecation-7-custom-types",
+                "Update or remove the following index templates before upgrading to 8.0: "
+                    + templatesWithCustomTypes
+                    + ". See https://ela.st/es-deprecation-7-removal-of-types for alternatives to mapping types.",
+                false,
+                null
+            );
+        } else {
+            // There were multiple mapping types, so at least one of them had to be a custom type as well
+            Set<String> allBadTemplates = new TreeSet<>();
+            allBadTemplates.addAll(templatesWithMultipleTypes);
+            allBadTemplates.addAll(templatesWithCustomTypes);
+            deprecationIssue = new DeprecationIssue(
+                DeprecationIssue.Level.CRITICAL,
+                "Multiple mapping types and custom mapping types in index templates and indices are deprecated",
+                "https://ela.st/es-deprecation-7-multiple-types",
+                "Update or remove the following index templates before upgrading to 8.0: "
+                    + templatesWithMultipleTypes
+                    + ". See https://ela.st/es-deprecation-7-removal-of-types for alternatives to mapping types.",
+                false,
+                null
+            );
         }
-        return new DeprecationIssue(
-            DeprecationIssue.Level.CRITICAL,
-            "Multiple mapping types in index templates and indices is not supported",
-            "https://ela.st/es-deprecation-7-multiple-types",
-            "Update or remove the following index templates before upgrading to 8.0: "
-                + templatesWithMultipleTypes
-                + ". See https://ela.st/es-deprecation-7-removal-of-types for alternatives to mapping types.",
-            false,
-            null
-        );
+        return deprecationIssue;
     }
 
     static DeprecationIssue checkClusterRoutingAllocationIncludeRelocationsSetting(final ClusterState clusterState) {

x-pack/plugin/deprecation/src/main/java/org/elasticsearch/xpack/deprecation/DeprecationChecks.java

@@ -49,7 +49,7 @@ private DeprecationChecks() {}
             ClusterDeprecationChecks::checkTemplatesWithTooManyFields,
             ClusterDeprecationChecks::checkPollIntervalTooLow,
             ClusterDeprecationChecks::checkTemplatesWithFieldNamesDisabled,
-            ClusterDeprecationChecks::checkTemplatesWithMultipleTypes,
+            ClusterDeprecationChecks::checkTemplatesWithCustomAndMultipleTypes,
             ClusterDeprecationChecks::checkClusterRoutingAllocationIncludeRelocationsSetting,
             ClusterDeprecationChecks::checkGeoShapeTemplates,
             ClusterDeprecationChecks::checkSparseVectorTemplates,

x-pack/plugin/deprecation/src/test/java/org/elasticsearch/xpack/deprecation/ClusterDeprecationChecksTests.java

@@ -347,7 +347,7 @@ public void testIndexTemplatesWithMultipleTypes() throws IOException {
             .build();
         IndexTemplateMetadata singleType = IndexTemplateMetadata.builder("single-type")
             .patterns(Collections.singletonList("foo"))
-            .putMapping("type1", "{\"type1\":{}}")
+            .putMapping("_doc", "{\"type1\":{}}")
             .build();
         ImmutableOpenMap<String, IndexTemplateMetadata> templates = ImmutableOpenMap.<String, IndexTemplateMetadata>builder()
             .fPut("multiple-types", multipleTypes)
@@ -375,6 +375,37 @@ public void testIndexTemplatesWithMultipleTypes() throws IOException {
         assertThat(DeprecationChecks.filterChecks(CLUSTER_SETTINGS_CHECKS, c -> c.apply(goodState)), hasSize(0));
     }
 
+    public void testIndexTemplatesWithCustomTypes() throws IOException {
+        IndexTemplateMetadata template1 = IndexTemplateMetadata.builder("template1")
+            .patterns(Collections.singletonList("foo"))
+            .putMapping("type1", "{\"type1\":{}}")
+            .build();
+        IndexTemplateMetadata template2 = IndexTemplateMetadata.builder("template2")
+            .patterns(Collections.singletonList("foo"))
+            .putMapping("type2", "{\"type2\":{}}")
+            .build();
+        IndexTemplateMetadata template3 = IndexTemplateMetadata.builder("template3")
+            .patterns(Collections.singletonList("foo"))
+            .putMapping("_doc", "{\"_doc\":{}}")
+            .build();
+        ImmutableOpenMap<String, IndexTemplateMetadata> templates = ImmutableOpenMap.<String, IndexTemplateMetadata>builder()
+            .fPut("template1", template1)
+            .fPut("template2", template2)
+            .fPut("template3", template3)
+            .build();
+        Metadata badMetadata = Metadata.builder().templates(templates).build();
+        ClusterState badState = ClusterState.builder(new ClusterName("test")).metadata(badMetadata).build();
+        List<DeprecationIssue> issues = DeprecationChecks.filterChecks(CLUSTER_SETTINGS_CHECKS, c -> c.apply(badState));
+        assertThat(issues, hasSize(1));
+        assertThat(
+            issues.get(0).getDetails(),
+            equalTo(
+                "Update or remove the following index templates before upgrading to 8.0: [template1, template2]. See "
+                    + "https://ela.st/es-deprecation-7-removal-of-types for alternatives to mapping types."
+            )
+        );
+    }
+
     public void testClusterRoutingAllocationIncludeRelocationsSetting() {
         boolean settingValue = randomBoolean();
         String settingKey = CLUSTER_ROUTING_ALLOCATION_INCLUDE_RELOCATIONS_SETTING.getKey();