From 7198bd7db784d4a2dc4890106e586f0b607ce080 Mon Sep 17 00:00:00 2001
From: epriestley <git@epriestley.com>
Date: Tue, 27 Aug 2019 15:27:25 -0700
Subject: [PATCH] When "utf8mb4" is available, use it as the default client
 charset when invoking standalone "mysql" commands

Summary:
Fixes T13390. We have some old code which doesn't dynamically select between "utf8mb4" and "utf8". This can lead to dumping utf8mb4 data over a utf8 connection in `bin/storage dump`, which possibly corrupts some emoji/whales.

Instead, prefer "utf8mb4" if it's available.

Test Plan: Ran `bin/storage dump` and `bin/storage shell`, saw sub-commands select utf8mb4 as the client charset.

Maniphest Tasks: T13390

Differential Revision: https://secure.phabricator.com/D20742
---
 .../management/PhabricatorStorageManagementAPI.php        | 8 ++++++++
 .../workflow/PhabricatorStorageManagementDumpWorkflow.php | 4 +++-
 .../PhabricatorStorageManagementShellWorkflow.php         | 4 ++--
 3 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/src/infrastructure/storage/management/PhabricatorStorageManagementAPI.php b/src/infrastructure/storage/management/PhabricatorStorageManagementAPI.php
index e66ba784f7..b838c8a5d9 100644
--- a/src/infrastructure/storage/management/PhabricatorStorageManagementAPI.php
+++ b/src/infrastructure/storage/management/PhabricatorStorageManagementAPI.php
@@ -298,6 +298,14 @@ final class PhabricatorStorageManagementAPI extends Phobject {
     return self::isCharacterSetAvailableOnConnection($character_set, $conn);
   }
 
+  public function getClientCharset() {
+    if ($this->isCharacterSetAvailable('utf8mb4')) {
+      return 'utf8mb4';
+    } else {
+      return 'utf8';
+    }
+  }
+
   public static function isCharacterSetAvailableOnConnection(
     $character_set,
     AphrontDatabaseConnection $conn) {
diff --git a/src/infrastructure/storage/management/workflow/PhabricatorStorageManagementDumpWorkflow.php b/src/infrastructure/storage/management/workflow/PhabricatorStorageManagementDumpWorkflow.php
index 28b188a873..3a18578a30 100644
--- a/src/infrastructure/storage/management/workflow/PhabricatorStorageManagementDumpWorkflow.php
+++ b/src/infrastructure/storage/management/workflow/PhabricatorStorageManagementDumpWorkflow.php
@@ -179,7 +179,9 @@ final class PhabricatorStorageManagementDumpWorkflow
     $argv = array();
     $argv[] = '--hex-blob';
     $argv[] = '--single-transaction';
-    $argv[] = '--default-character-set=utf8';
+
+    $argv[] = '--default-character-set';
+    $argv[] = $api->getClientCharset();
 
     if ($args->getArg('for-replica')) {
       $argv[] = '--master-data';
diff --git a/src/infrastructure/storage/management/workflow/PhabricatorStorageManagementShellWorkflow.php b/src/infrastructure/storage/management/workflow/PhabricatorStorageManagementShellWorkflow.php
index 0bf185a086..f376ea3e14 100644
--- a/src/infrastructure/storage/management/workflow/PhabricatorStorageManagementShellWorkflow.php
+++ b/src/infrastructure/storage/management/workflow/PhabricatorStorageManagementShellWorkflow.php
@@ -31,8 +31,8 @@ final class PhabricatorStorageManagementShellWorkflow
     }
 
     return phutil_passthru(
-      'mysql --protocol=TCP --default-character-set=utf8mb4 '.
-      '-u %s %C -h %s %C',
+      'mysql --protocol=TCP --default-character-set %R -u %s %C -h %s %C',
+      $api->getClientCharset(),
       $api->getUser(),
       $flag_password,
       $host,