SERVER-40446 Add "NonResumableChangeStreamError" error label

Give the "NonRetryableChangeStreamError" error class a more
appropriate name and propagate it to an "errorLabel" in the command
response.

jstests/change_streams/error_label.js

@@ -0,0 +1,33 @@
+/**
+ * Test that an erroneous Change Stream pipeline responds with an error that includes the
+ * "NonResumableChangeStreamError" label.
+ */
+
+(function() {
+    "use strict";
+
+    load("jstests/libs/collection_drop_recreate.js");  // For assertDropAndRecreateCollection.
+
+    // Drop and recreate the collections to be used in this set of tests.
+    const coll = assertDropAndRecreateCollection(db, "change_stream_error_label");
+
+    // Attaching a projection to the Change Stream that filters out the resume token (stored in the
+    // _id field) guarantees a ChangeStreamFatalError as soon as we get the first change.
+    const changeStream = coll.watch([{$project: {_id: 0}}], {batchSize: 1});
+    assert.commandWorked(coll.insert({a: 1}));
+
+    const err = assert.throws(function() {
+        // Call hasNext() until it throws an error or unexpectedly returns true. We need the
+        // assert.soon() to keep trying here, because the above insert command isn't immediately
+        // observable to the change stream in sharded configurations.
+        assert.soon(function() {
+            return changeStream.hasNext();
+        });
+    });
+
+    // The hasNext() sends a getMore command, which should generate a ChangeStreamFatalError reply
+    // that includes the NonResumableChangeStreamError errorLabel.
+    assert.commandFailedWithCode(err, ErrorCodes.ChangeStreamFatalError);
+    assert("errorLabels" in err, err);
+    assert.contains("NonResumableChangeStreamError", err.errorLabels, err);
+}());

src/mongo/base/error_codes.err

@@ -357,4 +357,4 @@ error_class("SnapshotError", ["SnapshotTooOld", "SnapshotUnavailable", "StaleChu
 
 error_class("VoteAbortError", ["NoSuchTransaction", "TransactionTooOld"])
 
-error_class("NonRetryableChangeStreamError", ["ChangeStreamFatalError", "ChangeStreamHistoryLost"])
+error_class("NonResumableChangeStreamError", ["ChangeStreamFatalError", "ChangeStreamHistoryLost"])

src/mongo/db/handle_request_response.cpp

@@ -36,23 +36,26 @@ BSONObj getErrorLabels(const OperationSessionInfoFromClient& sessionOptions,
                        const std::string& commandName,
                        ErrorCodes::Error code,
                        bool hasWriteConcernError) {
+    BSONArrayBuilder labelArray;
 
-    // By specifying "autocommit", the user indicates they want to run a transaction.
-    // It is always false when set.
-    if (!sessionOptions.getAutocommit()) {
-        return {};
+    // Note that we only apply the TransientTxnError label if the "autocommit" field is present in
+    // the session options. When present, "autocommit" will always be false, so we don't check its
+    // value.
+    if (sessionOptions.getAutocommit() &&
+        isTransientTransactionError(code,
+                                    hasWriteConcernError,
+                                    commandName == "commitTransaction" ||
+                                        commandName == "coordinateCommitTransaction")) {
+        // An error code for which isTransientTransactionError() is true indicates a transaction
+        // failure with no persistent side effects.
+        labelArray << txn::TransientTxnErrorFieldName;
     }
 
-    // The errors that indicate the transaction fails without any persistent side-effect.
-    bool isTransient = isTransientTransactionError(
-        code,
-        hasWriteConcernError,
-        commandName == "commitTransaction" || commandName == "coordinateCommitTransaction");
-
-    if (isTransient) {
-        return BSON("errorLabels" << BSON_ARRAY(txn::TransientTxnErrorFieldName));
+    if (ErrorCodes::isNonResumableChangeStreamError(code)) {
+        labelArray << "NonResumableChangeStreamError";
     }
-    return {};
+
+    return (labelArray.arrSize() > 0) ? BSON("errorLabels" << labelArray.arr()) : BSONObj();
 }
 
 }  // namespace mongo