X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=t%2Fprefetch%2Fmultiple_hasmany.t;h=ca89d55b84db97de5404fb088bb24c4aea1e30b6;hb=7cc643b453ec0373b31624ffd3b09b07b925ac3e;hp=6ef7a5337b515822168c694278515c139956d7a4;hpb=e9bd1473080b4aaf94e2be97329d74703d41a353;p=dbsrgits%2FDBIx-Class-Historic.git

diff --git a/t/prefetch/multiple_hasmany.t b/t/prefetch/multiple_hasmany.t
index 6ef7a53..ca89d55 100644
--- a/t/prefetch/multiple_hasmany.t
+++ b/t/prefetch/multiple_hasmany.t
@@ -5,32 +5,13 @@ use Test::More;
 use Test::Exception;
 use lib qw(t/lib);
 use DBICTest;
-use Data::Dumper;
-
-my $schema = DBICTest->init_schema();
-
-my $orig_debug = $schema->storage->debug;
-
 use IO::File;
 
-BEGIN {
-    eval "use DBD::SQLite";
-    plan $@
-        ? ( skip_all => 'needs DBD::SQLite for testing' )
-        : ( tests => 16 );
-}
+plan tests => 10;
+
+my $schema = DBICTest->init_schema();
+my $sdebug = $schema->storage->debug;
 
-# figure out if we've got a version of sqlite that is older than 3.2.6, in
-# which case COUNT(DISTINCT()) doesn't work
-my $is_broken_sqlite = 0;
-my ($sqlite_major_ver,$sqlite_minor_ver,$sqlite_patch_ver) =
-    split /\./, $schema->storage->dbh->get_info(18);
-if( $schema->storage->dbh->get_info(17) eq 'SQLite' &&
-    ( ($sqlite_major_ver < 3) ||
-      ($sqlite_major_ver == 3 && $sqlite_minor_ver < 2) ||
-      ($sqlite_major_ver == 3 && $sqlite_minor_ver == 2 && $sqlite_patch_ver < 6) ) ) {
-    $is_broken_sqlite = 1;
-}
 
 # once the following TODO is complete, remove the 2 warning tests immediately
 # after the TODO block
@@ -63,6 +44,9 @@ TODO: {
     ok(! $o_mm_warn, 'no warning on attempt to prefetch several same level has_many\'s (1 -> M + M)');
 
     is($queries, 1, 'prefetch one->(has_many,has_many) ran exactly 1 query');
+    $schema->storage->debugcb (undef);
+    $schema->storage->debug ($sdebug);
+
     is($pr_tracks_count, $tracks_count, 'equal count of prefetched relations over several same level has_many\'s (1 -> M + M)');
 
     for ($pr_tracks_rs, $tracks_rs) {
@@ -98,6 +82,8 @@ TODO: {
     ok(! $m_o_mm_warn, 'no warning on attempt to prefetch several same level has_many\'s (M -> 1 -> M + M)');
 
     is($queries, 1, 'prefetch one->(has_many,has_many) ran exactly 1 query');
+    $schema->storage->debugcb (undef);
+    $schema->storage->debug ($sdebug);
 
     is($pr_tags_count, $tags_count, 'equal count of prefetched relations over several same level has_many\'s (M -> 1 -> M + M)');
 
@@ -109,22 +95,61 @@ TODO: {
 }
 
 # remove this closure once the TODO above is working
-my $w;
 {
-    local $SIG{__WARN__} = sub { $w = shift };
+    my $warn_re = qr/will explode the number of row objects retrievable via/;
+
+    my (@w, @dummy);
+    local $SIG{__WARN__} = sub { $_[0] =~ $warn_re ? push @w, @_ : warn @_ };
 
     my $rs = $schema->resultset('CD')->search ({ 'me.title' => 'Forkful of bees' }, { prefetch => [qw/tracks tags/] });
-    for (qw/all count next first/) {
-        undef $w;
-        my @stuff = $rs->search()->$_;
-        like ($w, qr/will currently disrupt both the functionality of .rs->count\(\), and the amount of objects retrievable via .rs->next\(\)/,
-            "warning on ->$_ attempt prefetching several same level has_manys (1 -> M + M)");
-    }
+    @w = ();
+    @dummy = $rs->first;
+    is (@w, 1, 'warning on attempt prefetching several same level has_manys (1 -> M + M)');
+
     my $rs2 = $schema->resultset('LinerNotes')->search ({ notes => 'Buy Whiskey!' }, { prefetch => { cd => [qw/tags tracks/] } });
-    for (qw/all count next first/) {
-        undef $w;
-        my @stuff = $rs2->search()->$_;
-        like ($w, qr/will currently disrupt both the functionality of .rs->count\(\), and the amount of objects retrievable via .rs->next\(\)/,
-            "warning on ->$_ attempt prefetching several same level has_manys (M -> 1 -> M + M)");
-    }
+    @w = ();
+    @dummy = $rs2->first;
+    is (@w, 1, 'warning on attempt prefetching several same level has_manys (M -> 1 -> M + M)');
 }
+
+__END__
+The solution is to rewrite ResultSet->_collapse_result() and
+ResultSource->resolve_prefetch() to focus on the final results from the collapse
+of the data. Right now, the code doesn't treat the columns from the various
+tables as grouped entities. While there is a concept of hierarchy (so that
+prefetching down relationships does work as expected), there is no idea of what
+the final product should look like and how the various columns in the row would
+play together. So, the actual prefetch datastructure from the search would be
+very useful in working through this problem. We already have access to the PKs
+and sundry for those. So, when collapsing the search result, we know we are
+looking for 1 cd object. We also know we're looking for tracks and tags records
+-independently- of each other. So, we can grab the data for tracks and data for
+tags separately, uniqueing on the PK as appropriate. Then, when we're done with
+the given cd object's datastream, we know we're good. This should work for all
+the various scenarios.
+
+My reccommendation is the row's data is preprocessed first, breaking it up into
+the data for each of the component tables. (This could be done in the single
+table case, too, but probably isn't necessary.) So, starting with something
+like:
+  my $row = {
+    t1.col1 => 1,
+    t1.col2 => 2,
+    t2.col1 => 3,
+    t2.col2 => 4,
+    t3.col1 => 5,
+    t3.col2 => 6,
+  };
+it is massaged to look something like:
+  my $row_massaged = {
+    t1 => { col1 => 1, col2 => 2 },
+    t2 => { col1 => 3, col2 => 4 },
+    t3 => { col1 => 5, col2 => 6 },
+  };
+At this point, find the stuff that's different is easy enough to do and slotting
+things into the right spot is, likewise, pretty straightforward. Instead of
+storing things in a AoH, store them in a HoH keyed on the PKs of the the table,
+then convert to an AoH after all collapsing is done.
+
+This implies that the collapse attribute can probably disappear or, at the
+least, be turned into a boolean (which is how it's used in every other place).