Merged PR 1768548: [Revert] Ignore collation spec in aggregate and find queries

### Does this PR have any customer impact?
Yes

### Type (Feature, Refactoring, Bugfix, DevOps, Testing, Perf, etc)
Revert

### Does it involve schema level changes? (Table, Column, Index, UDF, etc level changes)
No

### Are you introducing any new config? If yes, do you have tests with and without them being set?
No

### ChangeLog (Refer [Template](../oss/CHANGELOG.md))
- Ignore collation spec for find and aggregate queries

### Description

Ignore collation spec for find and aggregate queries

----
#### AI description  (iteration 1)
#### PR Classification
This PR reverts recent changes to collation handling in aggregate and find queries, ensuring that collation specifications are ignored when the feature is disabled.

#### PR Summary
The PR modifies the collation processing in aggregation and find queries by gating the handling of the "collation" field with the EnableCollation flag—removing the error path when the flag is off—and updates test expectations accordingly.
- `oss/pg_documentdb/src/aggregation/bson_aggregation_pipeline.c`: Adjusted the collation handling to check `EnableCollation` before processing and removed the branch that raised errors.
- Test expectation files in both `oss/internal/pg_documentdb_distributed` and `pgmongo/src/test/docdb_compat/expected`: Updated expected outputs (including subplan identifiers) and added commands to toggle the collation feature.
- `oss/internal/pg_documentdb_distributed/src/test/regress/sql/bson_dollar_ops_collation_tests_runtime.sql`: Modified to set collation off during tests, ensuring that collation specs are ignored without throwing an error.
<!-- GitOpsUserAgent=GitOps.Apps.Server.pullrequestcopilot -->

Author: diipak-bisht

internal/pg_documentdb_distributed/src/test/regress/expected/bson_dollar_ops_collation_tests_runtime.out

@@ -2,7 +2,6 @@ SET search_path to documentdb_core,documentdb_api,documentdb_api_catalog,pg_cata
 SET citus.next_shard_id TO 7990000;
 SET documentdb.next_collection_id TO 7990;
 SET documentdb.next_collection_index_id TO 7990;
-SET documentdb_core.enableCollation TO on;
 -- (1) insert some docs
 SELECT documentdb_api.insert_one('db', 'ci_search', '{ "_id": 1, "a": "Cat" }');
 NOTICE:  creating collection
@@ -161,6 +160,24 @@ SELECT documentdb_api.insert_one('db', 'ci_search', '{ "_id": 26, "a": [{ "b": "
  { "n" : { "$numberInt" : "1" }, "ok" : { "$numberDouble" : "1.0" } }
 (1 row)
 
+SET documentdb_core.enableCollation TO off;
+-- With collation off and colation string in find and aggregate commands should not throw an error
+SELECT document FROM bson_aggregation_pipeline('db', '{ "aggregate": "ci_search", "pipeline": [ { "$sort": { "_id": 1 } }, { "$match": { "a": { "$eq": "cat" } } } ], "cursor": {}, "collation": { "locale": "en", "strength" : 1}  }');
+                               document                                
+---------------------------------------------------------------------
+ { "_id" : { "$numberInt" : "3" }, "a" : "cat" }
+ { "_id" : { "$numberInt" : "18" }, "a" : [ "dog", "cat", "CAT" ] }
+ { "_id" : { "$numberInt" : "19" }, "a" : [ "cat", "rabbit", "bAt" ] }
+ { "_id" : { "$numberInt" : "22" }, "a" : [ "cat" ] }
+(4 rows)
+
+SELECT document FROM bson_aggregation_find('db', '{ "find": "ci_search", "filter": { "b": { "$eq": "cat" } }, "sort": { "_id": 1 }, "skip": 0, "limit": 5, "collation": { "locale": "en", "strength" : 1} }');
+                     document                     
+---------------------------------------------------------------------
+ { "_id" : { "$numberInt" : "11" }, "b" : "cat" }
+(1 row)
+
+SET documentdb_core.enableCollation TO on;
 -- (2) Find query unsharded collection
 SELECT document FROM bson_aggregation_find('db', '{ "find": "ci_search", "filter": { "a": { "$eq": "cat" } }, "sort": { "_id": 1 }, "skip": 0, "limit": 5, "collation": { "locale": "en", "strength" : 1} }');
                               document                              
@@ -2041,7 +2058,7 @@ EXPLAIN (VERBOSE ON, COSTS OFF) SELECT document FROM bson_aggregation_pipeline('
 ---------------------------------------------------------------------
  Custom Scan (Citus Adaptive)
    Output: remote_scan.document
-   ->  Distributed Subplan 376_1
+   ->  Distributed Subplan 378_1
          ->  Custom Scan (Citus Adaptive)
                Output: remote_scan.document, remote_scan.lookup_filter
                Task Count: 8
@@ -2051,7 +2068,7 @@ EXPLAIN (VERBOSE ON, COSTS OFF) SELECT document FROM bson_aggregation_pipeline('
                      Node: host=localhost port=58070 dbname=regression
                      ->  Seq Scan on documentdb_data.documents_7997_7990200 collection
                            Output: document, documentdb_api_internal.bson_dollar_lookup_extract_filter_expression(document, '{ "_id" : "_id", "collation" : "en-u-ks-level1" }'::documentdb_core.bson)
-   ->  Distributed Subplan 376_2
+   ->  Distributed Subplan 378_2
          ->  Custom Scan (Citus Adaptive)
                Output: remote_scan.document
                Task Count: 8
@@ -2065,18 +2082,18 @@ EXPLAIN (VERBOSE ON, COSTS OFF) SELECT document FROM bson_aggregation_pipeline('
    Task Count: 1
    Tasks Shown: All
    ->  Task
-         Query: SELECT documentdb_api_internal.bson_dollar_merge_documents(lookup_stage_1.document, "lookupRight_stage_1".document, true) AS document FROM ((SELECT intermediate_result.document, intermediate_result.lookup_filter FROM read_intermediate_result('376_1'::text, 'binary'::citus_copy_format) intermediate_result(document documentdb_core.bson, lookup_filter documentdb_core.bson)) lookup_stage_1 JOIN LATERAL (SELECT COALESCE(documentdb_api_catalog.bson_array_agg(lookup_right_query_stage_0.document, 'matched_docs'::text), '{ "matched_docs" : [  ] }'::documentdb_core.bson) AS document FROM (SELECT intermediate_result.document FROM read_intermediate_result('376_2'::text, 'binary'::citus_copy_format) intermediate_result(document documentdb_core.bson)) lookup_right_query_stage_0 WHERE documentdb_api_internal.bson_dollar_lookup_join_filter(lookup_right_query_stage_0.document, lookup_stage_1.lookup_filter, '_id'::text)) "lookupRight_stage_1" ON (true))
+         Query: SELECT documentdb_api_internal.bson_dollar_merge_documents(lookup_stage_1.document, "lookupRight_stage_1".document, true) AS document FROM ((SELECT intermediate_result.document, intermediate_result.lookup_filter FROM read_intermediate_result('378_1'::text, 'binary'::citus_copy_format) intermediate_result(document documentdb_core.bson, lookup_filter documentdb_core.bson)) lookup_stage_1 JOIN LATERAL (SELECT COALESCE(documentdb_api_catalog.bson_array_agg(lookup_right_query_stage_0.document, 'matched_docs'::text), '{ "matched_docs" : [  ] }'::documentdb_core.bson) AS document FROM (SELECT intermediate_result.document FROM read_intermediate_result('378_2'::text, 'binary'::citus_copy_format) intermediate_result(document documentdb_core.bson)) lookup_right_query_stage_0 WHERE documentdb_api_internal.bson_dollar_lookup_join_filter(lookup_right_query_stage_0.document, lookup_stage_1.lookup_filter, '_id'::text)) "lookupRight_stage_1" ON (true))
          Node: host=localhost port=58070 dbname=regression
          ->  Nested Loop
                Output: documentdb_api_internal.bson_dollar_merge_documents(intermediate_result.document, (COALESCE(documentdb_api_catalog.bson_array_agg(intermediate_result_1.document, 'matched_docs'::text), '{ "matched_docs" : [  ] }'::documentdb_core.bson)), true)
                ->  Function Scan on pg_catalog.read_intermediate_result intermediate_result
                      Output: intermediate_result.document, intermediate_result.lookup_filter
-                     Function Call: read_intermediate_result('376_1'::text, 'binary'::citus_copy_format)
+                     Function Call: read_intermediate_result('378_1'::text, 'binary'::citus_copy_format)
                ->  Aggregate
                      Output: COALESCE(documentdb_api_catalog.bson_array_agg(intermediate_result_1.document, 'matched_docs'::text), '{ "matched_docs" : [  ] }'::documentdb_core.bson)
                      ->  Function Scan on pg_catalog.read_intermediate_result intermediate_result_1
                            Output: intermediate_result_1.document
-                           Function Call: read_intermediate_result('376_2'::text, 'binary'::citus_copy_format)
+                           Function Call: read_intermediate_result('378_2'::text, 'binary'::citus_copy_format)
                            Filter: documentdb_api_internal.bson_dollar_lookup_join_filter(intermediate_result_1.document, intermediate_result.lookup_filter, '_id'::text)
 (39 rows)
 
@@ -2103,7 +2120,7 @@ EXPLAIN (VERBOSE ON, COSTS OFF) SELECT document FROM bson_aggregation_pipeline('
 ---------------------------------------------------------------------
  Custom Scan (Citus Adaptive)
    Output: remote_scan.document
-   ->  Distributed Subplan 384_1
+   ->  Distributed Subplan 386_1
          ->  Custom Scan (Citus Adaptive)
                Output: remote_scan.document, remote_scan.lookup_filter
                Task Count: 8
@@ -2113,7 +2130,7 @@ EXPLAIN (VERBOSE ON, COSTS OFF) SELECT document FROM bson_aggregation_pipeline('
                      Node: host=localhost port=58070 dbname=regression
                      ->  Seq Scan on documentdb_data.documents_7997_7990200 collection
                            Output: document, documentdb_api_internal.bson_dollar_lookup_extract_filter_expression(document, '{ "a.b" : "a.b", "collation" : "en-u-ks-level1" }'::documentdb_core.bson)
-   ->  Distributed Subplan 384_2
+   ->  Distributed Subplan 386_2
          ->  Custom Scan (Citus Adaptive)
                Output: remote_scan.document
                Task Count: 8
@@ -2127,18 +2144,18 @@ EXPLAIN (VERBOSE ON, COSTS OFF) SELECT document FROM bson_aggregation_pipeline('
    Task Count: 1
    Tasks Shown: All
    ->  Task
-         Query: SELECT documentdb_api_internal.bson_dollar_merge_documents(lookup_stage_1.document, "lookupRight_stage_1".document, true) AS document FROM ((SELECT intermediate_result.document, intermediate_result.lookup_filter FROM read_intermediate_result('384_1'::text, 'binary'::citus_copy_format) intermediate_result(document documentdb_core.bson, lookup_filter documentdb_core.bson)) lookup_stage_1 JOIN LATERAL (SELECT COALESCE(documentdb_api_catalog.bson_array_agg(lookup_right_query_stage_0.document, 'matched_docs'::text), '{ "matched_docs" : [  ] }'::documentdb_core.bson) AS document FROM (SELECT intermediate_result.document FROM read_intermediate_result('384_2'::text, 'binary'::citus_copy_format) intermediate_result(document documentdb_core.bson)) lookup_right_query_stage_0 WHERE documentdb_api_internal.bson_dollar_lookup_join_filter(lookup_right_query_stage_0.document, lookup_stage_1.lookup_filter, 'a.b'::text)) "lookupRight_stage_1" ON (true))
+         Query: SELECT documentdb_api_internal.bson_dollar_merge_documents(lookup_stage_1.document, "lookupRight_stage_1".document, true) AS document FROM ((SELECT intermediate_result.document, intermediate_result.lookup_filter FROM read_intermediate_result('386_1'::text, 'binary'::citus_copy_format) intermediate_result(document documentdb_core.bson, lookup_filter documentdb_core.bson)) lookup_stage_1 JOIN LATERAL (SELECT COALESCE(documentdb_api_catalog.bson_array_agg(lookup_right_query_stage_0.document, 'matched_docs'::text), '{ "matched_docs" : [  ] }'::documentdb_core.bson) AS document FROM (SELECT intermediate_result.document FROM read_intermediate_result('386_2'::text, 'binary'::citus_copy_format) intermediate_result(document documentdb_core.bson)) lookup_right_query_stage_0 WHERE documentdb_api_internal.bson_dollar_lookup_join_filter(lookup_right_query_stage_0.document, lookup_stage_1.lookup_filter, 'a.b'::text)) "lookupRight_stage_1" ON (true))
          Node: host=localhost port=58070 dbname=regression
          ->  Nested Loop
                Output: documentdb_api_internal.bson_dollar_merge_documents(intermediate_result.document, (COALESCE(documentdb_api_catalog.bson_array_agg(intermediate_result_1.document, 'matched_docs'::text), '{ "matched_docs" : [  ] }'::documentdb_core.bson)), true)
                ->  Function Scan on pg_catalog.read_intermediate_result intermediate_result
                      Output: intermediate_result.document, intermediate_result.lookup_filter
-                     Function Call: read_intermediate_result('384_1'::text, 'binary'::citus_copy_format)
+                     Function Call: read_intermediate_result('386_1'::text, 'binary'::citus_copy_format)
                ->  Aggregate
                      Output: COALESCE(documentdb_api_catalog.bson_array_agg(intermediate_result_1.document, 'matched_docs'::text), '{ "matched_docs" : [  ] }'::documentdb_core.bson)
                      ->  Function Scan on pg_catalog.read_intermediate_result intermediate_result_1
                            Output: intermediate_result_1.document
-                           Function Call: read_intermediate_result('384_2'::text, 'binary'::citus_copy_format)
+                           Function Call: read_intermediate_result('386_2'::text, 'binary'::citus_copy_format)
                            Filter: documentdb_api_internal.bson_dollar_lookup_join_filter(intermediate_result_1.document, intermediate_result.lookup_filter, 'a.b'::text)
 (39 rows)
 

internal/pg_documentdb_distributed/src/test/regress/sql/bson_dollar_ops_collation_tests_runtime.sql

@@ -3,8 +3,6 @@ SET citus.next_shard_id TO 7990000;
 SET documentdb.next_collection_id TO 7990;
 SET documentdb.next_collection_index_id TO 7990;
 
-SET documentdb_core.enableCollation TO on;
-
 -- (1) insert some docs
 SELECT documentdb_api.insert_one('db', 'ci_search', '{ "_id": 1, "a": "Cat" }');
 SELECT documentdb_api.insert_one('db', 'ci_search', '{ "_id": 2, "a": "dog" }');
@@ -33,6 +31,13 @@ SELECT documentdb_api.insert_one('db', 'ci_search', '{ "_id": 24, "a": ["cAt"] }
 SELECT documentdb_api.insert_one('db', 'ci_search', '{ "_id": 25, "a": { "b" : "cAt"} }');
 SELECT documentdb_api.insert_one('db', 'ci_search', '{ "_id": 26, "a": [{ "b": "CAT"}] }');
 
+SET documentdb_core.enableCollation TO off;
+
+-- With collation off and colation string in find and aggregate commands should not throw an error
+SELECT document FROM bson_aggregation_pipeline('db', '{ "aggregate": "ci_search", "pipeline": [ { "$sort": { "_id": 1 } }, { "$match": { "a": { "$eq": "cat" } } } ], "cursor": {}, "collation": { "locale": "en", "strength" : 1}  }');
+SELECT document FROM bson_aggregation_find('db', '{ "find": "ci_search", "filter": { "b": { "$eq": "cat" } }, "sort": { "_id": 1 }, "skip": 0, "limit": 5, "collation": { "locale": "en", "strength" : 1} }');
+
+SET documentdb_core.enableCollation TO on;
 
 -- (2) Find query unsharded collection
 SELECT document FROM bson_aggregation_find('db', '{ "find": "ci_search", "filter": { "a": { "$eq": "cat" } }, "sort": { "_id": 1 }, "skip": 0, "limit": 5, "collation": { "locale": "en", "strength" : 1} }');

pg_documentdb/src/aggregation/bson_aggregation_pipeline.c

@@ -1266,19 +1266,13 @@ GenerateAggregationQuery(text *database, pgbson *aggregationSpec, QueryData *que
 		else if (StringViewEqualsCString(&keyView, "collation"))
 		{
 			ReportFeatureUsage(FEATURE_COLLATION);
-
 			if (EnableCollation)
 			{
+				/* Ignore collation until enabled for aggregate */
 				EnsureTopLevelFieldType("collation", &aggregationIterator,
 										BSON_TYPE_DOCUMENT);
 				ParseAndGetCollationString(value, context.collationString);
 			}
-			else
-			{
-				ereport(ERROR, (errcode(ERRCODE_DOCUMENTDB_COMMANDNOTSUPPORTED),
-								errmsg(
-									"aggregation with collation is not currently supported.")));
-			}
 		}
 		else if (setStatementTimeout &&
 				 StringViewEqualsCString(&keyView, "maxTimeMS"))
@@ -1539,20 +1533,13 @@ GenerateFindQuery(text *databaseDatum, pgbson *findSpec, QueryData *queryData, b
 				if (StringViewEqualsCString(&keyView, "collation"))
 				{
 					ReportFeatureUsage(FEATURE_COLLATION);
-
 					if (EnableCollation)
 					{
+						/* Ignore collation until enabled for find */
 						EnsureTopLevelFieldType("collation", &findIterator,
 												BSON_TYPE_DOCUMENT);
 						ParseAndGetCollationString(value, context.collationString);
 					}
-					else
-					{
-						ereport(ERROR, (errcode(ERRCODE_DOCUMENTDB_COMMANDNOTSUPPORTED),
-										errmsg(
-											"Find with collation is not currently supported.")));
-					}
-
 					continue;
 				}