Don't auto-vivify clustered_key hashref in PTDEBUG.

bin/pt-duplicate-key-checker

@@ -2188,8 +2188,9 @@ sub get_duplicate_keys {
 
    my $clustered_key = $args{clustered_key} ? $keys{$args{clustered_key}}
                      : undef;
-   PTDEBUG && _d('clustered key:', $clustered_key->{name},
+   PTDEBUG && _d('clustered key:',
-      $clustered_key->{colnames});
+      $clustered_key ? ($clustered_key->{name}, $clustered_key->{colnames})
+                     : 'none');
    if ( $clustered_key
         && $args{clustered}
         && $args{tbl_info}->{engine}

lib/DuplicateKeyFinder.pm

@@ -148,8 +148,9 @@ sub get_duplicate_keys {
    # Remove clustered duplicates.
    my $clustered_key = $args{clustered_key} ? $keys{$args{clustered_key}}
                      : undef;
-   PTDEBUG && _d('clustered key:', $clustered_key->{name},
+   PTDEBUG && _d('clustered key:',
-      $clustered_key->{colnames});
+      $clustered_key ? ($clustered_key->{name}, $clustered_key->{colnames})
+                     : 'none');
    if ( $clustered_key
         && $args{clustered}
         && $args{tbl_info}->{engine}

t/lib/DuplicateKeyFinder.t

@@ -9,7 +9,7 @@ BEGIN {
 use strict;
 use warnings FATAL => 'all';
 use English qw(-no_match_vars);
-use Test::More tests => 38;
+use Test::More;
 
 use VersionParser;
 use DuplicateKeyFinder;
@@ -786,4 +786,5 @@ like(
    qr/Complete test coverage/,
    '_d() works'
 );
+done_testing;
 exit;

t/pt-duplicate-key-checker/clustered_keys.t

@@ -22,9 +22,6 @@ my $dbh = $sb->get_dbh_for('master');
 if ( !$dbh ) {
    plan skip_all => 'Cannot connect to sandbox master';
 }
-else {
-   plan tests => 2;
-}
 
 my $cnf    = "/tmp/12345/my.sandbox.cnf";
 my $sample = "t/pt-duplicate-key-checker/samples/";
@@ -46,9 +43,47 @@ ok(
    "Shorten, not remove, clustered dupes"
 );
 
+# #############################################################################
+# Error if InnoDB table has no PK or unique indexes
+# https://bugs.launchpad.net/percona-toolkit/+bug/1036804
+# #############################################################################
+$sb->load_file('master', "t/pt-duplicate-key-checker/samples/idb-no-uniques-bug-894140.sql");
+
+# PTDEBUG was auto-vivifying $clustered_key:
+#
+#    PTDEBUG && _d('clustered key:', $clustered_key->{name},
+#       $clustered_key->{colnames});
+#
+#    if ( $clustered_key
+#         && $args{clustered}
+#         && $args{tbl_info}->{engine}
+#         && $args{tbl_info}->{engine} =~ m/InnoDB/i )
+#    {
+#          push @dupes, $self->remove_clustered_duplicates($clustered_key...
+#
+#    sub remove_clustered_duplicates {
+#       my ( $self, $ck, $keys, %args ) = @_;
+#       die "I need a ck argument"   unless $ck;
+#       die "I need a keys argument" unless $keys;
+#       my $ck_cols = $ck->{colnames};
+#       my @dupes;
+#       KEY:
+#       for my $i ( 0 .. @$keys - 1 ) {
+#          my $key = $keys->[$i]->{colnames};
+#          if ( $key =~ m/$ck_cols$/ ) {
+
+my $output = `PTDEBUG=1 $trunk/bin/pt-duplicate-key-checker F=$cnf -d bug_1036804 2>&1`;
+
+unlike(
+   $output,
+   qr/Use of uninitialized value/,
+   'PTDEBUG doesn\'t auto-vivify cluster key hashref (bug 1036804)'
+);
+
 # #############################################################################
 # Done.
 # #############################################################################
 $sb->wipe_clean($dbh);
 ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+done_testing;
 exit;

t/pt-duplicate-key-checker/samples/idb-no-uniques-bug-894140.sql

@@ -0,0 +1,9 @@
+DROP DATABASE IF EXISTS bug_1036804;
+CREATE DATABASE bug_1036804;
+USE bug_1036804;
+CREATE TABLE `t` (
+  `col1` int(11) DEFAULT NULL,
+  `col2` int(11) DEFAULT NULL,
+  KEY `col1` (`col1`),
+  KEY `col2` (`col2`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1;