fix: Don't add indices on columns with UNIQUE constraint

t/86sqlt-no-indices-on-unique-cols.t

@@ -0,0 +1,95 @@
+use strict;
+use warnings;
+use Data::Dumper;
+use SQL::Translator;    # Why isn't that neccessary in t/86sqlt.t?
+
+use Test::More;
+use lib qw(t/lib);
+use DBICTest;
+
+BEGIN {
+    require DBIx::Class;
+    plan skip_all => 'Test needs '
+        . DBIx::Class::Optional::Dependencies->req_missing_for('deploy')
+        unless DBIx::Class::Optional::Dependencies->req_ok_for('deploy');
+} ## end BEGIN
+
+note(
+    q(Checking there are no additional indices on first columns of unique constraints)
+);
+
+note q(Change schema initialization to deploy automatically);
+my $schema = DBICTest->init_schema(no_deploy => 1, no_populate => 1);
+note q(Remove the custom deployment callback);
+for my $t ($schema->sources) {
+    $schema->source($t)->sqlt_deploy_callback(
+        sub {
+            my ($self, $table) = @_;
+            note qq(Table resource $table was just deployed);
+            $self->default_sqlt_deploy_hook($table);
+        }
+    );
+} ## end for my $t ($schema->sources)
+$schema->deploy;
+
+my $translator = SQL::Translator->new(
+    parser_args   => { dbic_schema => $schema },
+    parser        => q(SQL::Translator::Parser::DBIx::Class),
+    producer_args => {},
+) or die SQL::Translator->error;
+my $tschema = $translator->schema;
+
+TABLE: for ($schema->sources()) {
+    my $source     = $schema->source($_);
+    my $table_name = $source->name;
+    note(
+        Data::Dumper->Dump(
+            [$_, $table_name],
+            [qw( schema_source source_name_before )]
+        )
+    );
+    my $tablename_type = ref $table_name;
+    if ($tablename_type) {
+        if ($tablename_type eq 'SCALAR') {
+            $tablename_type = $$table_name;
+        }
+        else {
+            note qq($_ type is skipped for unexpected type: $tablename_type);
+            next TABLE;
+        }
+    } ## end if ($tablename_type)
+    note(
+        Data::Dumper->Dump(
+            [$_, $table_name],
+            [qw( schema_source source_name_after )]
+        )
+    );
+
+    my %ucs = $source->unique_constraints;
+    my @uc_first_cols = map { $ucs{$_}->[0] } keys %ucs;
+
+    note qq(Searching indices of table $table_name);
+    my $_t = $tschema->get_table($table_name);  # why are tables not populated??
+    unless ($_t) {
+        note qq(Table not found: $table_name);
+        next;
+    }
+
+    my @index_first_cols = $_t->get_indices;
+
+    # table "cd" is my first demonstration
+    note(
+        explain(
+            {
+                $table_name => {
+                    unique_constraints => [@uc_first_cols],
+                    relations          => [@index_first_cols],
+                }
+            }
+        )
+    ) if $_ eq q(CD);
+} ## end TABLE: for ($schema->sources)
+
+fail(q(!!! REMOVE ME WHEN FINISHED !!!));
+
+done_testing();