From 0352d88621c1d3794197105f7fef97e669c40179 Mon Sep 17 00:00:00 2001
From: Luca Cavanna <javanna@users.noreply.github.com>
Date: Fri, 22 Jun 2018 09:57:32 +0200
Subject: [PATCH] Get Mapping API to honour allow_no_indices and
 ignore_unavailable (#31507)

Get Mapping currently throws index not found exception (and returns
404 status code) from the REST layer whenever an index was specified
and no indices have been returned. We should not have this logic in the
REST layer though as only our index resolver should decide whether we
need to throw exceptions or not based on provided indices and corresponding
indices options.

Closes #31485
---
 .../indices.get_mapping/30_missing_index.yml  | 21 +++++++++++++++++++
 .../50_wildcard_expansion.yml                 | 16 +++++++++++++-
 .../admin/indices/RestGetMappingAction.java   | 12 +++--------
 3 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/30_missing_index.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/30_missing_index.yml
index cf4e5b56e786e..4d3abb292f467 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/30_missing_index.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/30_missing_index.yml
@@ -13,3 +13,24 @@
       indices.get_mapping:
         index: test_index
 
+---
+"Index missing, ignore_unavailable=true":
+  - skip:
+      version: " - 6.99.99"
+      reason: ignore_unavailable was ignored in previous versions
+  - do:
+      indices.get_mapping:
+        index: test_index
+        ignore_unavailable: true
+
+  - match: { '':  {} }
+
+---
+"Index missing, ignore_unavailable=true, allow_no_indices=false":
+  - do:
+      catch: missing
+      indices.get_mapping:
+        index: test_index
+        ignore_unavailable: true
+        allow_no_indices: false
+
diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/50_wildcard_expansion.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/50_wildcard_expansion.yml
index a0552f395edb5..d1a95b2690745 100644
--- a/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/50_wildcard_expansion.yml
+++ b/rest-api-spec/src/main/resources/rest-api-spec/test/indices.get_mapping/50_wildcard_expansion.yml
@@ -94,12 +94,26 @@ setup:
 
 ---
 "Get test-* with wildcard_expansion=none":
+ - skip:
+    version: " - 6.99.99"
+    reason: allow_no_indices (defaults to true) was ignored in previous versions
  - do:
-    catch: missing
     indices.get_mapping:
         index: test-x*
         expand_wildcards: none
 
+ - match: { '':  {} }
+---
+"Get test-* with wildcard_expansion=none allow_no_indices=false":
+ - skip:
+    version: " - 6.99.99"
+    reason: allow_no_indices was ignored in previous versions
+ - do:
+    catch: missing
+    indices.get_mapping:
+        index: test-x*
+        expand_wildcards: none
+        allow_no_indices: false
 ---
 "Get test-* with wildcard_expansion=open,closed":
 
diff --git a/server/src/main/java/org/elasticsearch/rest/action/admin/indices/RestGetMappingAction.java b/server/src/main/java/org/elasticsearch/rest/action/admin/indices/RestGetMappingAction.java
index 08f8449b7017f..f5d99bbb46ca1 100644
--- a/server/src/main/java/org/elasticsearch/rest/action/admin/indices/RestGetMappingAction.java
+++ b/server/src/main/java/org/elasticsearch/rest/action/admin/indices/RestGetMappingAction.java
@@ -32,7 +32,6 @@
 import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
-import org.elasticsearch.index.IndexNotFoundException;
 import org.elasticsearch.indices.TypeMissingException;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.BytesRestResponse;
@@ -89,14 +88,9 @@ public RestChannelConsumer prepareRequest(final RestRequest request, final NodeC
             @Override
             public RestResponse buildResponse(final GetMappingsResponse response, final XContentBuilder builder) throws Exception {
                 final ImmutableOpenMap<String, ImmutableOpenMap<String, MappingMetaData>> mappingsByIndex = response.getMappings();
-                if (mappingsByIndex.isEmpty() && (indices.length != 0 || types.length != 0)) {
-                    if (indices.length != 0 && types.length == 0) {
-                        builder.close();
-                        return new BytesRestResponse(channel, new IndexNotFoundException(String.join(",", indices)));
-                    } else {
-                        builder.close();
-                        return new BytesRestResponse(channel, new TypeMissingException("_all", String.join(",", types)));
-                    }
+                if (mappingsByIndex.isEmpty() && types.length != 0) {
+                    builder.close();
+                    return new BytesRestResponse(channel, new TypeMissingException("_all", String.join(",", types)));
                 }
 
                 final Set<String> typeNames = new HashSet<>();