SERVER-71638 Don't let to hide the last shard key index using a key pattern

4 files changed, 15 insertions, 6 deletions

diff --git a/etc/backports_required_for_multiversion_tests.yml b/etc/backports_required_for_multiversion_tests.yml
index 6834273a58a..8819f0e52bd 100644
--- a/etc/backports_required_for_multiversion_tests.yml
+++ b/etc/backports_required_for_multiversion_tests.yml
@@ -290,6 +290,8 @@ last-continuous:
     ticket: SERVER-71667
   - test_file: jstests/sharding/drop_collection.js
     ticket: SERVER-71689
+  - test_file: jstests/sharding/hidden_index.js
+    ticket: SERVER-71638
   suites: null
 last-lts:
   all:
@@ -655,4 +657,6 @@ last-lts:
     ticket: SERVER-71667
   - test_file: jstests/sharding/drop_collection.js
     ticket: SERVER-71689
+  - test_file: jstests/sharding/hidden_index.js
+    ticket: SERVER-71638
   suites: null
diff --git a/jstests/noPassthrough/collmod_convert_to_unique_sharded.js b/jstests/noPassthrough/collmod_convert_to_unique_sharded.js
index 0a02ffd1c1e..5f486497b75 100644
--- a/jstests/noPassthrough/collmod_convert_to_unique_sharded.js
+++ b/jstests/noPassthrough/collmod_convert_to_unique_sharded.js
@@ -57,8 +57,7 @@ assert.commandFailedWithCode(shardedColl.insert({_id: 4, a: 2}), ErrorCodes.Dupl
 
 // Try converting the index to unique and make sure no indexes are converted on any shards.
 assert.commandFailedWithCode(
-    db.runCommand(
-        {collMod: shardedColl.getName(), index: {keyPattern: {a: 1}, hidden: true, unique: true}}),
+    db.runCommand({collMod: shardedColl.getName(), index: {keyPattern: {a: 1}, unique: true}}),
     ErrorCodes.CannotConvertIndexToUnique);
 
 const s0Coll = st.shard0.getDB(jsTestName()).getCollection("sharded");
@@ -78,8 +77,8 @@ assert.eq(countPrepareUniqueIndexes(s1Coll, {a: 1}),
 
 // Remove the duplicate and confirm the indexes are converted.
 assert.commandWorked(shardedColl.deleteOne({_id: 2}));
-assert.commandWorked(db.runCommand(
-    {collMod: shardedColl.getName(), index: {keyPattern: {a: 1}, hidden: true, unique: true}}));
+assert.commandWorked(
+    db.runCommand({collMod: shardedColl.getName(), index: {keyPattern: {a: 1}, unique: true}}));
 assert.eq(countUniqueIndexes(s0Coll, {a: 1}),
           1,
           'index should be unique: ' + tojson(s0Coll.getIndexes()));
@@ -88,4 +87,4 @@ assert.eq(countUniqueIndexes(s1Coll, {a: 1}),
           'index should be unique: ' + tojson(s1Coll.getIndexes()));
 
 st.stop();
-})();
\ No newline at end of file
+})();
diff --git a/jstests/sharding/hidden_index.js b/jstests/sharding/hidden_index.js
index 6bf2c00cdf5..5dfdce03dfb 100644
--- a/jstests/sharding/hidden_index.js
+++ b/jstests/sharding/hidden_index.js
@@ -36,6 +36,7 @@ function validateHiddenIndexBehaviour() {
 
 // Check that command will fail when we try to hide the only shard key index of the collection
 function validateOneShardKeyHiddenIndexBehaviour() {
+    assert.commandFailedWithCode(coll.hideIndex({skey: 1}), ErrorCodes.InvalidOptions);
     assert.commandFailedWithCode(coll.hideIndex("skey_1"), ErrorCodes.InvalidOptions);
     assert.commandFailedWithCode(
         testDb.runCommand({"collMod": coll.getName(), "index": {"name": "skey_1", "hidden": true}}),
@@ -48,6 +49,11 @@ function validateDifferentHiddenIndexesBehaviour() {
     // Create index on skey
     assert.commandWorked(coll.createIndex({skey: 1, anotherkey: 1}));
 
+    // Check that is possible to hide a shard key index using its key pattern
+    assert.commandWorked(coll.hideIndex({skey: 1}));
+    assert.commandWorked(coll.unhideIndex({skey: 1}));
+
+    // Check that is possible to hide a shard key index using its name
     assert.commandWorked(testDb.runCommand(
         {"collMod": coll.getName(), "index": {"name": "skey_1", "hidden": true}}));
 
diff --git a/src/mongo/db/catalog/coll_mod.cpp b/src/mongo/db/catalog/coll_mod.cpp
index d0daf7d9872..a085acab5fa 100644
--- a/src/mongo/db/catalog/coll_mod.cpp
+++ b/src/mongo/db/catalog/coll_mod.cpp
@@ -300,7 +300,7 @@ StatusWith<std::pair<ParsedCollModRequest, BSONObj>> parseCollModRequest(Operati
                     if (isLastNonHiddenShardKeyIndex(opCtx,
                                                      coll,
                                                      coll->getIndexCatalog(),
-                                                     indexName.toString(),
+                                                     cmrIndex->idx->indexName(),
                                                      shardedColl.getKeyPattern().toBSON())) {
                         return {ErrorCodes::InvalidOptions,
                                 "Cannot hide the only compatible index for this collection's shard "