Remove the ability to index or query context suggestions without context

This is a follow up of elastic#30712 that removes the ability to index or query
and context enabled completion field without context.

Relates elastic#30712

docs/reference/migration/migrate_7_0/search.asciidoc

@@ -81,3 +81,10 @@ for a particular index with the index setting `index.max_regex_length`.
 
 Search requests with extra content after the main object will no longer be accepted
 by the `_search` endpoint. A parsing exception will be thrown instead.
+
+==== Context Completion Suggester
+
+The ability to query and index context enabled suggestions without context,
+deprecated in 6.x, has been removed. Context enabled suggestion queries
+without contexts have to visit every suggestion, which degrades the search performance
+considerably.

rest-api-spec/src/main/resources/rest-api-spec/test/suggest/30_context.yml

@@ -337,11 +337,10 @@ setup:
   - match:  { suggest.result.0.options.0.text: "foo" }
 
 ---
-"Indexing and Querying without contexts is deprecated":
+"Indexing and Querying without contexts is forbidden":
   - skip:
       version: " - 6.99.99"
-      reason: this feature was deprecated in 7.0
-      features: "warnings"
+      reason: this feature was removed in 7.0
 
   - do:
       index:
@@ -359,8 +358,7 @@ setup:
               color: "blue"
 
   - do:
-      warnings:
-        - "The ability to index a suggestion with no context on a context enabled completion field is deprecated and will be removed in the next major release."
+      catch: /Contexts are mandatory in context enabled completion field \[suggest_context\]/
       index:
         index: test
         type:  test
@@ -373,8 +371,7 @@ setup:
       indices.refresh: {}
 
   - do:
-      warnings:
-        - "The ability to query with no context on a context enabled completion field is deprecated and will be removed in the next major release."
+      catch: /Missing mandatory contexts in context query/
       search:
         body:
           suggest:
@@ -383,11 +380,8 @@ setup:
               completion:
                 field: suggest_context
 
-  - length: { suggest.result: 1  }
-
   - do:
-      warnings:
-        - "The ability to query with no context on a context enabled completion field is deprecated and will be removed in the next major release."
+      catch: /Missing mandatory contexts in context query/
       search:
         body:
           suggest:
@@ -397,11 +391,8 @@ setup:
                 field: suggest_context
                 contexts: {}
 
-  - length: { suggest.result: 1  }
-
   - do:
-      warnings:
-          - "The ability to query with no context on a context enabled completion field is deprecated and will be removed in the next major release."
+      catch: /Missing mandatory contexts in context query/
       search:
         body:
           suggest:
@@ -411,5 +402,3 @@ setup:
                 field: suggest_multi_contexts
                 contexts:
                   location: []
-
-  - length: { suggest.result: 1  }

rest-api-spec/src/main/resources/rest-api-spec/test/suggest/40_typed_keys.yml

@@ -19,8 +19,6 @@ setup:
                           "type" : "category"
 
   - do:
-      warnings:
-        - "The ability to index a suggestion with no context on a context enabled completion field is deprecated and will be removed in the next major release."
       bulk:
         refresh: true
         index: test
@@ -29,18 +27,12 @@ setup:
           - '{"index": {}}'
           - '{"title": "Elasticsearch in Action", "suggestions": {"input": "ELK in Action", "contexts": {"format": "ebook"}}}'
           - '{"index": {}}'
-          - '{"title": "Elasticsearch - The Definitive Guide", "suggestions": {"input": ["Elasticsearch in Action"]}}'
+          - '{"title": "Elasticsearch - The Definitive Guide", "suggestions": {"input": ["Elasticsearch in Action"], "contexts": {"format": "ebook"}}}'
 
 ---
 "Test typed keys parameter for suggesters":
-  - skip:
-      version: " - 6.99.99"
-      reason: queying a context suggester with no context was deprecated in 7.0
-      features: "warnings"
 
   - do:
-      warnings:
-        - "The ability to query with no context on a context enabled completion field is deprecated and will be removed in the next major release."
       search:
         typed_keys: true
         body:
@@ -51,10 +43,6 @@ setup:
             term_suggester:
               term:
                 field: title
-            completion_suggester:
-              prefix: "Elastic"
-              completion:
-                field: suggestions
             context_suggester:
               prefix: "Elastic"
               completion:
@@ -66,6 +54,5 @@ setup:
                 field: title
 
   - is_true: suggest.term#term_suggester
-  - is_true: suggest.completion#completion_suggester
   - is_true: suggest.completion#context_suggester
   - is_true: suggest.phrase#phrase_suggester

server/src/main/java/org/elasticsearch/search/suggest/completion/context/ContextMappings.java

@@ -124,7 +124,7 @@ private class TypedContextField extends ContextSuggestField {
         private final ParseContext.Document document;
 
         TypedContextField(String name, String value, int weight, Map<String, Set<CharSequence>> contexts,
-                                 ParseContext.Document document) {
+                          ParseContext.Document document) {
             super(name, value, weight);
             this.contexts = contexts;
             this.document = document;
@@ -150,8 +150,7 @@ protected Iterable<CharSequence> contexts() {
                 }
             }
             if (typedContexts.isEmpty()) {
-                DEPRECATION_LOGGER.deprecated("The ability to index a suggestion with no context on a context enabled completion field" +
-                    " is deprecated and will be removed in the next major release.");
+                throw new IllegalArgumentException("Contexts are mandatory in context enabled completion field [" + name + "]");
             }
             return typedContexts;
         }
@@ -186,8 +185,7 @@ public ContextQuery toContextQuery(CompletionQuery query, Map<String, List<Conte
             }
         }
         if (hasContext == false) {
-            DEPRECATION_LOGGER.deprecated("The ability to query with no context on a context enabled completion field is deprecated " +
-                "and will be removed in the next major release.");
+            throw new IllegalArgumentException("Missing mandatory contexts in context query");
         }
         return typedContextQuery;
     }