SERVER-63481 Add `disallowNewDuplicateKeys` to `createIndex`

4 files changed, 93 insertions, 6 deletions

diff --git a/jstests/core/index_disallowNewDuplicateKeys.js b/jstests/core/index_disallowNewDuplicateKeys.js
new file mode 100644
index 00000000000..cbcdee2ce9e
--- /dev/null
+++ b/jstests/core/index_disallowNewDuplicateKeys.js
@@ -0,0 +1,53 @@
+/**
+ * Tests that the createIndex command accepts a disallowNewDuplicateKeys field and works accordingly
+ * then.
+ *
+ * @tags: [requires_fcv_53]
+ */
+(function() {
+"use strict";
+
+const coll = db.index_disallowNewDuplicateKeys;
+coll.drop();
+
+const collModIndexUniqueEnabled = assert
+                                      .commandWorked(db.getMongo().adminCommand(
+                                          {getParameter: 1, featureFlagCollModIndexUnique: 1}))
+                                      .featureFlagCollModIndexUnique.value;
+
+if (!collModIndexUniqueEnabled) {
+    jsTestLog('Skipping test because the collMod unique index feature flag is disabled.');
+    return;
+}
+
+assert.commandWorked(coll.insert({_id: 0, a: 1}));
+
+// Starts rejecting new duplicate keys.
+assert.commandWorked(coll.createIndex({a: 1}, {disallowNewDuplicateKeys: true}));
+
+// Disallows creating another index on the same key with a different option.
+assert.commandFailedWithCode(coll.createIndex({a: 1}, {disallowNewDuplicateKeys: false}),
+                             ErrorCodes.IndexOptionsConflict);
+
+// Checks the index is rejecting duplicates but accepting other keys.
+assert.commandFailedWithCode(coll.insert({_id: 1, a: 1}), ErrorCodes.DuplicateKey);
+assert.commandWorked(coll.insert({_id: 2, a: 2}));
+
+// Checks that the disallowNewDuplicateKeys field exists when getIndexes is called.
+let indexesWithComments = coll.getIndexes().filter(function(doc) {
+    return friendlyEqual(doc.disallowNewDuplicateKeys, true);
+});
+assert.eq(1, indexesWithComments.length);
+
+// Removes the field and checks the index works as a regular index.
+assert.commandWorked(coll.runCommand({
+    collMod: "index_disallowNewDuplicateKeys",
+    index: {keyPattern: {a: 1}, disallowNewDuplicateKeys: false}
+}));
+assert.commandWorked(coll.insert({_id: 1, a: 1}));
+
+indexesWithComments = coll.getIndexes().filter(function(doc) {
+    return friendlyEqual(doc.disallowNewDuplicateKeys, true);
+});
+assert.eq(0, indexesWithComments.length);
+})();
\ No newline at end of file
diff --git a/jstests/noPassthrough/collmod_index_noop.js b/jstests/noPassthrough/collmod_index_noop.js
index 77b83aa5e49..510b0448185 100644
--- a/jstests/noPassthrough/collmod_index_noop.js
+++ b/jstests/noPassthrough/collmod_index_noop.js
@@ -1,8 +1,8 @@
 /**
- * Validate that the 'collMod' command with 'hidden' or 'unique' fields will return expected result
- * document for the command and generate expected oplog entries in which the index modifications
- * (hiding/unhiding/convert to unique) will be no-ops if no other index option (TTL, for example)
- * is involved.
+ * Validate that the 'collMod' command with 'hidden,' 'unique,' or 'disallowNewDuplicateKeys' fields
+ * will return expected result document for the command and generate expected oplog entries in which
+ * the index modifications (hiding/unhiding/convert to unique/allowing duplicates/disallowing
+ * duplicates) will be no-ops if no other index option (TTL, for example) is involved.
  *
  * @tags: [
  *  # TODO(SERVER-61181): Fix validation errors under ephemeralForTest.
@@ -24,7 +24,7 @@ rst.startSet();
 rst.initiate();
 
 const dbName = jsTestName();
-const collName = "hidden_index";
+const collName = "collmod_index_noop";
 const primary = rst.getPrimary();
 const primaryDB = primary.getDB(dbName);
 const primaryColl = primaryDB[collName];
@@ -53,6 +53,10 @@ function validateResultForCollMod(result, expectedResult) {
     assert.eq(result.expireAfterSeconds_old, expectedResult.expireAfterSeconds_old, result);
     assert.eq(result.expireAfterSeconds_new, expectedResult.expireAfterSeconds_new, result);
     assert.eq(result.unique_new, expectedResult.unique_new, result);
+    assert.eq(
+        result.disallowNewDuplicateKeys_old, expectedResult.disallowNewDuplicateKeys_old, result);
+    assert.eq(
+        result.disallowNewDuplicateKeys_new, expectedResult.disallowNewDuplicateKeys_new, result);
 }
 
 primaryColl.drop();
@@ -64,6 +68,9 @@ assert.commandWorked(primaryColl.createIndex({e: 1}, {hidden: true, unique: true
 assert.commandWorked(primaryColl.createIndex({f: 1}, {unique: true, expireAfterSeconds: 15}));
 assert.commandWorked(
     primaryColl.createIndex({g: 1}, {hidden: true, unique: true, expireAfterSeconds: 25}));
+if (collModIndexUniqueEnabled) {
+    assert.commandWorked(primaryColl.createIndex({h: 1}, {disallowNewDuplicateKeys: true}));
+}
 
 // Hiding a non-hidden index will generate the oplog entry with a 'hidden_old: false'.
 let result = assert.commandWorked(primaryColl.hideIndex('a_1'));
@@ -213,6 +220,24 @@ if (collModIndexUniqueEnabled) {
     assert(idxSpec.hidden, tojson(idxSpec));
     assert.eq(idxSpec.expireAfterSeconds, 30);
     assert(idxSpec.unique, tojson(idxSpec));
+
+    // Validate that if the 'disallowNewDuplicateKeys' option is specified but is a no-op, the
+    // operation as a whole will be a no-op.
+    result = assert.commandWorked(primaryDB.runCommand({
+        "collMod": primaryColl.getName(),
+        "index": {"name": "h_1", "disallowNewDuplicateKeys": true},
+    }));
+    validateResultForCollMod(result, {});
+    validateCollModOplogEntryCount({
+        "o.index.name": "h_1",
+    },
+                                   0);
+
+    // Test that the index was unchanged.
+    idxSpec = GetIndexHelpers.findByName(primaryColl.getIndexes(), "h_1");
+    assert.eq(idxSpec.hidden, undefined);
+    assert.eq(idxSpec.expireAfterSeconds, undefined);
+    assert(idxSpec.disallowNewDuplicateKeys, tojson(idxSpec));
 }
 
 rst.stopSet();
diff --git a/src/mongo/db/catalog/index_catalog_impl.cpp b/src/mongo/db/catalog/index_catalog_impl.cpp
index 163d1807b57..431e35dfbb3 100644
--- a/src/mongo/db/catalog/index_catalog_impl.cpp
+++ b/src/mongo/db/catalog/index_catalog_impl.cpp
@@ -1754,6 +1754,10 @@ StatusWith<BSONObj> IndexCatalogImpl::_fixIndexSpec(OperationContext* opCtx,
     if (o["hidden"].trueValue())
         b.appendBool("hidden", true);  // normalize to bool true in case was int 1 or something...
 
+    if (o["disallowNewDuplicateKeys"].trueValue())
+        b.appendBool("disallowNewDuplicateKeys",
+                     true);  // normalize to bool true in case was int 1 or something...
+
     BSONObj key = fixIndexKey(o["key"].Obj());
     b.append("key", key);
 
@@ -1782,7 +1786,8 @@ StatusWith<BSONObj> IndexCatalogImpl::_fixIndexSpec(OperationContext* opCtx,
             } else if (s == "dropDups" || s == "ns") {
                 // dropDups is silently ignored and removed from the spec as of SERVER-14710.
                 // ns is removed from the spec as of 4.4.
-            } else if (s == "v" || s == "unique" || s == "key" || s == "name" || s == "hidden") {
+            } else if (s == "v" || s == "unique" || s == "key" || s == "name" || s == "hidden" ||
+                       s == "disallowNewDuplicateKeys") {
                 // covered above
             } else {
                 b.append(e);
diff --git a/src/mongo/db/create_indexes.idl b/src/mongo/db/create_indexes.idl
index 812b0e3a40f..33815ce79b8 100644
--- a/src/mongo/db/create_indexes.idl
+++ b/src/mongo/db/create_indexes.idl
@@ -180,6 +180,10 @@ structs:
                 type: safeBool
                 optional: true
                 unstable: false
+            disallowNewDuplicateKeys:
+                type: safeBool
+                optional: true
+                unstable: true
 commands:
     createIndexes:
         description: "Command for creating indexes on a collection"