Simplify deprecation issue levels (#36326)

This commit gets rid of the 'NONE' and 'INFO' severity levels for
deprecation issues.

'NONE' is unused and does not make much sense as a severity level.
'INFO' can be separated into two categories: Either 1) we can
definitively tell there will be a problem with the cluster/node/index
configuration that can be resolved prior to upgrade, in which case
the issue should be a WARNING, or 2) we can't, because any issues would
be at the application level, for which the user should review the
deprecation logs and/or response headers.

client/rest-high-level/src/main/java/org/elasticsearch/client/migration/DeprecationInfoResponse.java

@@ -141,8 +141,6 @@ public class DeprecationInfoResponse {
         }
 
         public enum Level {
-            NONE,
-            INFO,
             WARNING,
             CRITICAL
             ;

client/rest-high-level/src/test/java/org/elasticsearch/client/migration/DeprecationInfoResponseTests.java

@@ -30,6 +30,8 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import static org.elasticsearch.client.migration.DeprecationInfoResponse.DeprecationIssue.Level.CRITICAL;
+import static org.elasticsearch.client.migration.DeprecationInfoResponse.DeprecationIssue.Level.WARNING;
 import static org.elasticsearch.test.AbstractXContentTestCase.xContentTester;
 
 public class DeprecationInfoResponseTests extends ESTestCase {
@@ -94,7 +96,7 @@ public class DeprecationInfoResponseTests extends ESTestCase {
         // of elements for this list.
         int startingRandomNumber = canBeEmpty ? 0: 1;
         for (int i =0; i < randomIntBetween(startingRandomNumber, 2); i++) {
-            list.add(new DeprecationInfoResponse.DeprecationIssue(DeprecationInfoResponse.DeprecationIssue.Level.INFO,
+            list.add(new DeprecationInfoResponse.DeprecationIssue(randomFrom(WARNING, CRITICAL),
                 randomAlphaOfLength(5),
                 randomAlphaOfLength(5),
                 randomBoolean() ? randomAlphaOfLength(5) : null));

docs/reference/migration/apis/deprecation.asciidoc

@@ -49,20 +49,20 @@ Example response:
 {
   "cluster_settings" : [
     {
-      "level" : "info",
+      "level" : "critical",
-      "message" : "Network settings changes",
+      "message" : "Cluster name cannot contain ':'",
-      "url" : "{ref-60}/breaking_60_indices_changes.html#_index_templates_use_literal_index_patterns_literal_instead_of_literal_template_literal",
+      "url" : "{ref}/breaking-changes-7.0.html#_literal_literal_is_no_longer_allowed_in_cluster_name",
-      "details" : "templates using `template` field: watches,.monitoring-alerts,.watch-history-6,.ml-notifications,security-index-template,triggered_watches,.monitoring-es,.ml-meta,.ml-state,.monitoring-logstash,.ml-anomalies-,.monitoring-kibana"
+      "details" : "This cluster is named [mycompany:logging], which contains the illegal character ':'."
     }
   ],
   "node_settings" : [ ],
   "index_settings" : {
-    ".monitoring-es-6-2017.07.21" : [
+    "logs:apache" : [
       {
-        "level" : "info",
+        "level" : "warning",
-        "message" : "Coercion of boolean fields",
+        "message" : "Index name cannot contain ':'",
-        "url" : "{ref-60}/breaking_60_mappings_changes.html#_coercion_of_boolean_fields",
+        "url" : "{ref}/breaking-changes-7.0.html#_literal_literal_is_no_longer_allowed_in_index_name",
-        "details" : "[[type: doc, field: spins], [type: doc, field: mlockall], [type: doc, field: node_master], [type: doc, field: primary]]"
+        "details" : "This index is named [logs:apache], which contains the illegal character ':'."
       }
     ]
   }
@@ -79,7 +79,7 @@ The following is an example deprecation warning:
 ["source","js",subs="attributes,callouts,macros"]
 --------------------------------------------------
 {
-  "level" : "info",
+  "level" : "warning",
   "message" : "This is the generic descriptive message of the breaking change",
   "url" : "{ref-60}/breaking_60_indices_changes.html",
   "details" : "more information, like which nodes, indices, or settings are to blame"
@@ -91,10 +91,8 @@ As is shown, there is a `level` property that describes the significance of the
 issue.
 
 |=======
-|none | Everything is good.
-|info | An advisory note that something has changed. No action needed.
 |warning | You can upgrade directly, but you are using deprecated functionality
-which will not be available in the next major version.
+which will not be available or behave differently in the next major version.
 |critical | You cannot upgrade without fixing this problem.
 |=======
 

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

@@ -23,9 +23,14 @@ import java.util.Objects;
 public class DeprecationIssue implements Writeable, ToXContentObject {
 
     public enum Level implements Writeable {
-        NONE,
+        /**
-        INFO,
+         * Resolving this issue is advised but not required to upgrade. There may be undesired changes in behavior unless this issue is
+         * resolved before upgrading.
+         */
         WARNING,
+        /**
+         * This issue must be resolved to upgrade. Failures will occur unless this is resolved before upgrading.
+         */
         CRITICAL
         ;
 

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

@@ -38,7 +38,6 @@ public class DeprecationChecks {
     static List<Function<IndexMetaData, DeprecationIssue>> INDEX_SETTINGS_CHECKS =
         Collections.unmodifiableList(Arrays.asList(
             IndexDeprecationChecks::baseSimilarityDefinedCheck,
-            IndexDeprecationChecks::coercionCheck,
             IndexDeprecationChecks::dynamicTemplateWithMatchMappingTypeCheck,
             IndexDeprecationChecks::indexSharedFileSystemCheck,
             IndexDeprecationChecks::indexStoreTypeCheck,

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

@@ -79,23 +79,6 @@ public class IndexDeprecationChecks {
         return issues;
     }
 
-    static DeprecationIssue coercionCheck(IndexMetaData indexMetaData) {
-        if (indexMetaData.getCreationVersion().before(Version.V_6_0_0_alpha1)) {
-            List<String> issues = new ArrayList<>();
-            fieldLevelMappingIssue(indexMetaData, (mappingMetaData, sourceAsMap) -> {
-                issues.addAll(findInPropertiesRecursively(mappingMetaData.type(), sourceAsMap,
-                    property -> "boolean".equals(property.get("type"))));
-            });
-            if (issues.size() > 0) {
-                return new DeprecationIssue(DeprecationIssue.Level.INFO, "Coercion of boolean fields",
-                    "https://www.elastic.co/guide/en/elasticsearch/reference/master/" +
-                        "breaking_60_mappings_changes.html#_coercion_of_boolean_fields",
-                    issues.toString());
-            }
-        }
-        return null;
-    }
-
     static DeprecationIssue dynamicTemplateWithMatchMappingTypeCheck(IndexMetaData indexMetaData) {
         if (indexMetaData.getCreationVersion().before(Version.V_6_0_0_alpha1)) {
             List<String> issues = new ArrayList<>();