SERVER-56488 Change the default read concern to always be local

10 files changed, 22 insertions, 12 deletions

diff --git a/src/mongo/db/commands/count_cmd.cpp b/src/mongo/db/commands/count_cmd.cpp
index c53ffb44608..2d4769c5f86 100644
--- a/src/mongo/db/commands/count_cmd.cpp
+++ b/src/mongo/db/commands/count_cmd.cpp
@@ -97,7 +97,8 @@ public:
     }
 
     ReadConcernSupportResult supportsReadConcern(const BSONObj& cmdObj,
-                                                 repl::ReadConcernLevel level) const override {
+                                                 repl::ReadConcernLevel level,
+                                                 bool isImplicitDefault) const override {
         static const Status kSnapshotNotSupported{ErrorCodes::InvalidOptions,
                                                   "read concern snapshot not supported"};
         return {{level == repl::ReadConcernLevel::kSnapshotReadConcern, kSnapshotNotSupported},
diff --git a/src/mongo/db/commands/dbhash.cpp b/src/mongo/db/commands/dbhash.cpp
index 6ba7a8638dc..a17c4bc77c0 100644
--- a/src/mongo/db/commands/dbhash.cpp
+++ b/src/mongo/db/commands/dbhash.cpp
@@ -88,7 +88,8 @@ public:
     }
 
     ReadConcernSupportResult supportsReadConcern(const BSONObj& cmdObj,
-                                                 repl::ReadConcernLevel level) const final {
+                                                 repl::ReadConcernLevel level,
+                                                 bool isImplicitDefault) const final {
 
         static const Status kReadConcernNotSupported{ErrorCodes::InvalidOptions,
                                                      "read concern not supported"};
diff --git a/src/mongo/db/commands/distinct.cpp b/src/mongo/db/commands/distinct.cpp
index 2c01df647bc..6c9dba828d3 100644
--- a/src/mongo/db/commands/distinct.cpp
+++ b/src/mongo/db/commands/distinct.cpp
@@ -95,7 +95,8 @@ public:
     }
 
     ReadConcernSupportResult supportsReadConcern(const BSONObj& cmdObj,
-                                                 repl::ReadConcernLevel level) const override {
+                                                 repl::ReadConcernLevel level,
+                                                 bool isImplicitDefault) const override {
         return ReadConcernSupportResult::allSupportedAndDefaultPermitted();
     }
 
diff --git a/src/mongo/db/commands/find_cmd.cpp b/src/mongo/db/commands/find_cmd.cpp
index 669f133fab5..00d5f57c803 100644
--- a/src/mongo/db/commands/find_cmd.cpp
+++ b/src/mongo/db/commands/find_cmd.cpp
@@ -198,7 +198,8 @@ public:
             return false;
         }
 
-        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level) const final {
+        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level,
+                                                     bool isImplicitDefault) const final {
             return ReadConcernSupportResult::allSupportedAndDefaultPermitted();
         }
 
diff --git a/src/mongo/db/commands/getmore_cmd.cpp b/src/mongo/db/commands/getmore_cmd.cpp
index b2b407c65d6..88eb60eb201 100644
--- a/src/mongo/db/commands/getmore_cmd.cpp
+++ b/src/mongo/db/commands/getmore_cmd.cpp
@@ -277,7 +277,8 @@ public:
             return false;
         }
 
-        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level) const override {
+        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level,
+                                                     bool isImplicitDefault) const override {
             return kSupportsReadConcernResult;
         }
 
diff --git a/src/mongo/db/commands/killcursors_common.h b/src/mongo/db/commands/killcursors_common.h
index 4d906b66777..06ee9c9335d 100644
--- a/src/mongo/db/commands/killcursors_common.h
+++ b/src/mongo/db/commands/killcursors_common.h
@@ -74,11 +74,12 @@ public:
             return false;
         }
 
-        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level) const final {
+        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level,
+                                                     bool isImplicitDefault) const final {
             if constexpr (Impl::supportsReadConcern) {
                 return ReadConcernSupportResult::allSupportedAndDefaultPermitted();
             } else {
-                return KCV1Gen::InvocationBaseGen::supportsReadConcern(level);
+                return KCV1Gen::InvocationBaseGen::supportsReadConcern(level, isImplicitDefault);
             }
         }
 
diff --git a/src/mongo/db/commands/map_reduce_command_base.h b/src/mongo/db/commands/map_reduce_command_base.h
index bcc0870dfe5..f3806c40766 100644
--- a/src/mongo/db/commands/map_reduce_command_base.h
+++ b/src/mongo/db/commands/map_reduce_command_base.h
@@ -51,7 +51,8 @@ public:
      * the aggregate command.
      */
     virtual ReadConcernSupportResult supportsReadConcern(const BSONObj& cmdObj,
-                                                         repl::ReadConcernLevel level) const {
+                                                         repl::ReadConcernLevel level,
+                                                         bool isImplicitDefault) const {
         static const Status kReadConcernNotSupported{ErrorCodes::InvalidOptions,
                                                      "read concern not supported"};
         static const Status kDefaultReadConcernNotPermitted{ErrorCodes::InvalidOptions,
diff --git a/src/mongo/db/commands/pipeline_command.cpp b/src/mongo/db/commands/pipeline_command.cpp
index beed004686e..c3772f5af11 100644
--- a/src/mongo/db/commands/pipeline_command.cpp
+++ b/src/mongo/db/commands/pipeline_command.cpp
@@ -121,9 +121,11 @@ public:
             return true;
         }
 
-        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level) const override {
+        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level,
+                                                     bool isImplicitDefault) const override {
             return _liteParsedPipeline.supportsReadConcern(
                 level,
+                isImplicitDefault,
                 _aggregationRequest.getExplain(),
                 serverGlobalParams.enableMajorityReadConcern);
         }
diff --git a/src/mongo/db/commands/run_aggregate.cpp b/src/mongo/db/commands/run_aggregate.cpp
index 74874ee9e93..0c7b25d8520 100644
--- a/src/mongo/db/commands/run_aggregate.cpp
+++ b/src/mongo/db/commands/run_aggregate.cpp
@@ -472,8 +472,8 @@ boost::intrusive_ptr<ExpressionContext> makeExpressionContext(
  */
 void _adjustChangeStreamReadConcern(OperationContext* opCtx) {
     repl::ReadConcernArgs& readConcernArgs = repl::ReadConcernArgs::get(opCtx);
-    // There is already a read concern level set. Do nothing.
-    if (readConcernArgs.hasLevel()) {
+    // There is already a non-default read concern level set. Do nothing.
+    if (readConcernArgs.hasLevel() && !readConcernArgs.getProvenance().isImplicitDefault()) {
         return;
     }
     // We upconvert an empty read concern to 'majority'.
diff --git a/src/mongo/db/commands/txn_cmds.cpp b/src/mongo/db/commands/txn_cmds.cpp
index 9287537a5e2..9cac96afe54 100644
--- a/src/mongo/db/commands/txn_cmds.cpp
+++ b/src/mongo/db/commands/txn_cmds.cpp
@@ -185,7 +185,8 @@ public:
             return true;
         }
 
-        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level) const final {
+        ReadConcernSupportResult supportsReadConcern(repl::ReadConcernLevel level,
+                                                     bool isImplicitDefault) const final {
             // abortTransaction commences running inside a transaction (even though the transaction
             // will be ended by the time it completes).  Therefore it needs to accept any
             // readConcern which is valid within a transaction.  However it is not appropriate to