Fix $rs->populate with column name array but no row data

Two regressions for both context types snuck in during the the big populate()
rewrite d0cefd99

- In scalar context the return value incorrectly went from () to []
- In void context an empty $data was handed to ::Storage::_insert_bulk

diff --git a/lib/DBIx/Class/ResultSet.pm b/lib/DBIx/Class/ResultSet.pm
index 97dfe78..cdbbd6c 100644 (file)
--- a/lib/DBIx/Class/ResultSet.pm
+++ b/lib/DBIx/Class/ResultSet.pm
@@ -2248,6 +2248,8 @@ sub populate {
     my (@results, $guard);
 
     if (ref $data->[0] eq 'ARRAY') {
+      # column names only, nothing to do
+      return if @$data == 1;
 
       $guard = $self->result_source->schema->storage->txn_scope_guard
         if @$data > 2;
@@ -2290,6 +2292,8 @@ sub populate {
 
       # positional(!) explicit column list
       if ($i == 0) {
+        # column names only, nothing to do
+        return if @$data == 1;
 
         $colinfo->{$data->[0][$_]} = { pos => $_, name => $data->[0][$_] } and push @$colnames, $data->[0][$_]
           for 0 .. $#{$data->[0]};

diff --git a/t/100populate.t b/t/100populate.t
index e7cb830..fa07ba5 100644 (file)
--- a/t/100populate.t
+++ b/t/100populate.t
@@ -383,6 +383,7 @@ lives_ok {
 } 'literal+bind with semantically identical attrs works after normalization';
 
 # test all kinds of population with stringified objects
+# or with empty sets
 warnings_like {
   local $ENV{DBIC_RT79576_NOWARN};
 
@@ -438,10 +439,15 @@ warnings_like {
       [qw( rank name )],
       [ $rank, $fn ],
     ]},
+
+    'empty set' => { AoA => [
+      [qw( name rank )],
+    ]},
   };
 
   # generate the AoH equivalent based on the AoAs above
   for my $bag (values %$args) {
+    $bag->{AoH} = [];
     my @hdr = @{$bag->{AoA}[0]};
     for my $v ( @{$bag->{AoA}}[1..$#{$bag->{AoA}}] ) {
       push @{$bag->{AoH}}, my $h = {};

diff --git a/t/101populate_rs.t b/t/101populate_rs.t
index a592e56..5686c3e 100644 (file)
--- a/t/101populate_rs.t
+++ b/t/101populate_rs.t
@@ -13,6 +13,7 @@ use warnings;
 
 use Test::More;
 use Test::Warn;
+use Test::Exception;
 use lib qw(t/lib);
 use DBICTest;
 
@@ -704,6 +705,26 @@ ARRAYREF_OF_ARRAYREF_STYLE: {
   }
 }
 
-ok(eval { $art_rs->populate([]); 1 }, "Empty populate runs but does nothing");
+EMPTY_POPULATE: {
+  foreach(
+    [ empty         => [] ],
+    [ columns_only  => [ [qw(name rank charfield)] ] ],
+  ) {
+    my ($desc, $arg) = @{$_};
+
+    $schema->is_executed_sql_bind( sub {
+
+      my $rs = $art_rs;
+      lives_ok { $rs->populate($arg); 1 } "$desc populate in void context lives";
+
+      my @r = $art_rs->populate($arg);
+      is_deeply( \@r, [], "$desc populate in list context returns empty list" );
+
+      my $r = $art_rs->populate($arg);
+      is( $r, undef, "$desc populate in scalar context returns undef" );
+
+    }, [], "$desc populate executed no statements" );
+  }
+}
 
 done_testing;