PT-2377 - fixed pt-table-sync for JSON utf8 strings

The MySQL driver DBD::mysql does not decode JSON values as utf8
although MySQL uses utf8mb4 for all JSON strings.

This change decodes JSON values as utf8 (when not already done)
such that SQL statements are generated correctly.

bin/pt-table-sync

@@ -3612,6 +3612,14 @@ sub make_UPDATE {
       @cols = $self->sort_cols($row);
    }
    my $types = $self->{tbl_struct}->{type_for};
+
+   foreach my $col ( @cols ) {
+      my $is_json = ($types->{$col} || '') =~ m/json/i;
+      if ( $is_json && not utf8::is_utf8($row->{$col}) ) {
+         utf8::decode($row->{$col})
+      }
+   }
+
    return "UPDATE $self->{dst_db_tbl} SET "
       . join(', ', map {
             my $is_hex = ($types->{$_} || '') =~ m/^0x[0-9a-fA-F]+$/i;
@@ -3660,6 +3668,13 @@ sub make_row {
    my $q     = $self->{Quoter};
    my $type_for = $self->{tbl_struct}->{type_for};
 
+   foreach my $col ( @cols ) {
+      my $is_json = ($type_for->{$col} || '') =~ m/json/i;
+      if ( $is_json && not utf8::is_utf8($row->{$col}) ) {
+         utf8::decode($row->{$col})
+      }
+   }
+
    return "$verb INTO $self->{dst_db_tbl}("
       . join(', ', map { $q->quote($_) } @cols)
       . ') VALUES ('

lib/ChangeHandler.pm

@@ -324,6 +324,16 @@ sub make_UPDATE {
       @cols = $self->sort_cols($row);
    }
    my $types = $self->{tbl_struct}->{type_for};
+
+   # MySQL uses utf8mb4 for all strings in JSON, but
+   # DBD::mysql does not decode it accordingly
+   foreach my $col ( @cols ) {
+      my $is_json = ($types->{$col} || '') =~ m/json/i;
+      if ( $is_json && not utf8::is_utf8($row->{$col}) ) {
+         utf8::decode($row->{$col})
+      }
+   }
+
    return "UPDATE $self->{dst_db_tbl} SET "
       . join(', ', map {
             my $is_hex = ($types->{$_} || '') =~ m/^0x[0-9a-fA-F]+$/i;
@@ -403,6 +413,15 @@ sub make_row {
    my $q     = $self->{Quoter};
    my $type_for = $self->{tbl_struct}->{type_for};
 
+   # MySQL uses utf8mb4 for all strings in JSON, but
+   # DBD::mysql does not decode it accordingly
+   foreach my $col ( @cols ) {
+      my $is_json = ($type_for->{$col} || '') =~ m/json/i;
+      if ( $is_json && not utf8::is_utf8($row->{$col}) ) {
+         utf8::decode($row->{$col})
+      }
+   }
+
    return "$verb INTO $self->{dst_db_tbl}("
       . join(', ', map { $q->quote($_) } @cols)
       . ') VALUES ('

t/pt-table-sync/pt-2377.t

@@ -0,0 +1,80 @@
+#!/usr/bin/env perl
+
+BEGIN {
+   die "The PERCONA_TOOLKIT_BRANCH environment variable is not set.\n"
+      unless $ENV{PERCONA_TOOLKIT_BRANCH} && -d $ENV{PERCONA_TOOLKIT_BRANCH};
+   unshift @INC, "$ENV{PERCONA_TOOLKIT_BRANCH}/lib";
+};
+
+use strict;
+use warnings FATAL => 'all';
+use English qw(-no_match_vars);
+use Test::More;
+
+use PerconaTest;
+use Sandbox;
+require "$trunk/bin/pt-table-sync";
+
+my $dp = new DSNParser(opts=>$dsn_opts);
+my $sb = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+my $master_dbh = $sb->get_dbh_for('master');
+my $slave1_dbh = $sb->get_dbh_for('slave1');
+
+if ( !$master_dbh ) {
+   plan skip_all => 'Cannot connect to sandbox master';
+}
+elsif ( !$slave1_dbh ) {
+   plan skip_all => 'Cannot connect to sandbox slave1';
+}
+else {
+   plan tests => 3;
+}
+
+my $output;
+
+# #############################################################################
+# Test generated REPLACE statements.
+# #############################################################################
+$sb->load_file('master', "t/pt-table-sync/samples/pt-2377.sql");
+$sb->wait_for_slaves();
+$slave1_dbh->do("delete from `test`.`test_table` where `id`=1");
+
+$output = remove_traces(output(
+   sub { pt_table_sync::main('--sync-to-master',
+      'h=127.0.0.1,P=12346,u=msandbox,p=msandbox',
+      qw(-t test.test_table --print --execute))
+   },
+));
+chomp($output);
+is(
+   $output,
+   q/REPLACE INTO `test`.`test_table`(`id`, `data`) VALUES ('1', '{"name": "Müller"}');/,
+   "UTF8 characters of JSON values are printed correctly in REPLACE statements"
+);
+
+# #############################################################################
+# Test generated UPDATE statements.
+# #############################################################################
+$sb->load_file('master', "t/pt-table-sync/samples/pt-2377.sql");
+$sb->wait_for_slaves();
+$slave1_dbh->do(q/update `test`.`test_table` set `data`='{"reaction": "哈哈哈"}' where `id`=2/);
+
+$output = remove_traces(output(
+   sub { pt_table_sync::main(qw(--print --execute),
+      "h=127.0.0.1,P=12346,u=msandbox,p=msandbox,D=test,t=test_table",
+      "h=127.0.0.1,P=12345,u=msandbox,p=msandbox,D=test,t=test_table");
+   }
+));
+chomp($output);
+is(
+   $output,
+   q/UPDATE `test`.`test_table` SET `data`='{"reaction": "哈哈哈"}' WHERE `id`='2' LIMIT 1;/,
+   "UTF8 characters of JSON values are printed correctly in UPDATE statements"
+);
+
+# #############################################################################
+# Done.
+# #############################################################################
+$sb->wipe_clean($master_dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+exit;

t/pt-table-sync/samples/pt-2377.sql

@@ -0,0 +1,14 @@
+DROP DATABASE IF EXISTS test;
+CREATE DATABASE test;
+USE test;
+
+CREATE TABLE `test_table` (
+  `id` INT AUTO_INCREMENT PRIMARY KEY,
+  `data` JSON NOT NULL
+) ENGINE=InnoDB;
+
+INSERT INTO
+  `test_table` (`data`)
+VALUES
+  ('{"name": "Müller"}'),
+  ('{"reaction": "哈哈"}');