PT-1860 make pt-osc respect case insesitive lookup on Windows and osx

lib/TableParser.pm

@@ -325,11 +325,33 @@ sub check_table {
    }
    my ($dbh, $db, $tbl) = @args{@required_args};
    my $q      = $self->{Quoter} || 'Quoter';
+   $self->{check_table_error} = undef;
+
+   # https://dev.mysql.com/doc/refman/8.0/en/identifier-case-sensitivity.html
+   # MySQL may use use case-insensitive table lookup, this is controller by
+   # @@lower_case_table_names. 0 means case sensitive search, 1 or 2 means
+   # case insensitive lookup.
+
+   my $lctn_sql = 'SELECT @@lower_case_table_names';
+   PTDEBUG && _d($lctn_sql);
+
+   my $lower_case_table_names;
+   eval { ($lower_case_table_names) = $dbh->selectrow_array($lctn_sql); };
+   if ( my $e = $EVAL_ERROR ) {
+      PTDEBUG && _d($e);
+      $self->{check_table_error} = $e;
+      return 0;
+   }
+
+   PTDEBUG && _d("lower_case_table_names=$lower_case_table_names");
+   if ($lower_case_table_names > 0) {
+       PTDEBUG && _d("MySQL uses case-insensitive lookup, converting '$tbl' to lowercase");
+       $tbl = lc $tbl;
+   }
+
    my $db_tbl = $q->quote($db, $tbl);
    PTDEBUG && _d('Checking', $db_tbl);
 
-   $self->{check_table_error} = undef;
-
    my $sql = "SHOW TABLES FROM " . $q->quote($db)
            . ' LIKE ' . $q->literal_like($tbl);
    PTDEBUG && _d($sql);

t/pt-online-schema-change/case-insensitive.t

@@ -0,0 +1,84 @@
+#!/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 Time::HiRes qw(sleep);
+
+$ENV{PTTEST_FAKE_TS} = 1;
+$ENV{PERCONA_TOOLKIT_TEST_USE_DSN_NAMES} = 1;
+
+use PerconaTest;
+use Sandbox;
+require "$trunk/bin/pt-online-schema-change";
+require VersionParser;
+
+use Data::Dumper;
+$Data::Dumper::Indent    = 1;
+$Data::Dumper::Sortkeys  = 1;
+$Data::Dumper::Quotekeys = 0;
+
+my $dp         = new DSNParser(opts=>$dsn_opts);
+my $sb         = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+my $master_dbh = $sb->get_dbh_for('master');
+
+if ( !$master_dbh ) {
+   plan skip_all => 'Cannot connect to sandbox master';
+}
+
+my $q      = new Quoter();
+my $tp     = new TableParser(Quoter => $q);
+my @args   = qw(--set-vars innodb_lock_wait_timeout=3);
+my $output = "";
+my $dsn    = "h=127.1,P=12345,u=msandbox,p=msandbox";
+my $exit   = 0;
+my $sample = "t/pt-online-schema-change/samples";
+my $rows;
+
+# #############################################################################
+# Tool shouldn't run without --execute (bug 933232).
+# #############################################################################
+
+my ($lower_case_table_names) = $master_dbh->selectrow_array('SELECT @@lower_case_table_names');
+plan skip_all => 'MySQL uses case sensitive lookup' if $lower_case_table_names == 0;
+
+$sb->load_file('master', "$sample/basic_no_fks_innodb.sql");
+
+($output, $exit) = full_output(
+   sub { pt_online_schema_change::main(@args, "$dsn,D=pt_osc,t=T",
+      '--alter', 'drop column d', '--execute') }
+);
+
+like(
+   $output,
+   qr/Successfully altered/,
+   "Table is altered using capital name 'T'"
+) or diag($output);
+
+my $ddl = $master_dbh->selectrow_arrayref("show create table pt_osc.T");
+unlike(
+   $ddl->[1],
+   qr/^\s+["`]d["`]/m,
+   "'D' column is dropped"
+);
+
+is(
+   $exit,
+   0,
+   "Exit 0"
+);
+
+# #############################################################################
+# Done.
+# #############################################################################
+
+$sb->wipe_clean($master_dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+done_testing;