From 9a2a6db2a9c5e628b38a5c8cceb90e1e5dbc39a4 Mon Sep 17 00:00:00 2001
From: Jay Huh <jewoongh@meta.com>
Date: Tue, 1 Aug 2023 14:49:06 -0700
Subject: [PATCH] Use C++17 [[fallthrough]] in transaction_test.cc (#11663)

Summary:
(Copied from https://www.internalfb.com/diff/D46606060)

This diff makes its files safe for use with -Wimplicit-fallthrough. Now that we're using C+20 there's no reason not to use this C++17 feature to make our code safer.
It's currently possible to write code like this:
```
switch(x){
  case 1:
    foo1();
  case 2:
    foo2();
    break;
  case 3:
    foo3();
}
```
But that's scary because we don't know whether the fallthrough from case 1 was intentional or not.
The -Wimplicit-fallthrough flag will make this an error. The solution is to either  fix the bug by inserting break or indicating intention by using [[fallthrough]]; (from C++17).
```
switch(x){
  case 1:
    foo1();
    [[fallthrough]]; // Solution if we intended to fallthrough
    break;           // Solution if we did not intend to fallthrough
  case 2:
    foo2();
    break;
  case 3:
    foo3();
}
```

Pull Request resolved: https://github.com/facebook/rocksdb/pull/11663

Test Plan: Existing tests

Reviewed By: jowlyzhang

Differential Revision: D47961248

Pulled By: jaykorean

fbshipit-source-id: 0d374c721bf1b328c14949dc5c17693da7311d03
---
 utilities/transactions/transaction_test.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/utilities/transactions/transaction_test.cc b/utilities/transactions/transaction_test.cc
index ebe924fda..b46bac0d9 100644
--- a/utilities/transactions/transaction_test.cc
+++ b/utilities/transactions/transaction_test.cc
@@ -4990,7 +4990,7 @@ TEST_P(TransactionTest, DeleteRangeSupportTest) {
           }
           break;
         case WRITE_PREPARED:
-          // Intentional fall-through
+          FALLTHROUGH_INTENDED;
         case WRITE_UNPREPARED:
           if (skip_concurrency_control && skip_duplicate_key_check) {
             ASSERT_OK(s);