Teach genbki.pl to auto-generate pg_type entries for array types.

This eliminates some more tedium in adding new catalog entries,
specifically the need to set up an array type when adding a new
built-in data type.  Now it's sufficient to assign an OID for the
array type and write it in an "array_type_oid" metadata field.
You don't have to fill the base type's typarray link explicitly, either.

No catversion bump since the contents of pg_type aren't changed.
(Well, their order might be different, but that doesn't matter.)

John Naylor, reviewed and whacked around a bit by
Dagfinn Ilmari Mannsåker, and some more by me.

Discussion: https://postgr.es/m/CAJVSVGVTb6m9pJF49b3SuA8J+T-THO9c0hxOmoyv-yGKh-FbNg@mail.gmail.com

src/backend/catalog/Catalog.pm

@@ -191,6 +191,11 @@ sub ParseHeader
 					{
 						$column{default} = $1;
 					}
+					elsif (
+						$attopt =~ /BKI_ARRAY_DEFAULT\(['"]?([^'"]+)['"]?\)/)
+					{
+						$column{array_default} = $1;
+					}
 					elsif ($attopt =~ /BKI_LOOKUP\((\w+)\)/)
 					{
 						$column{lookup} = $1;
@@ -277,12 +282,16 @@ sub ParseData
 			}
 		}
 
-		# If we found a hash reference, keep it.
-		# Only keep non-data strings if we
-		# are told to preserve formatting.
+		# If we found a hash reference, keep it, unless it is marked as
+		# autogenerated; in that case it'd duplicate an entry we'll
+		# autogenerate below.  (This makes it safe for reformat_dat_file.pl
+		# with --full-tuples to print autogenerated entries, which seems like
+		# useful behavior for debugging.)
+		#
+		# Only keep non-data strings if we are told to preserve formatting.
 		if (defined $hash_ref)
 		{
-			push @$data, $hash_ref;
+			push @$data, $hash_ref if !$hash_ref->{autogenerated};
 		}
 		elsif ($preserve_formatting)
 		{
@@ -290,6 +299,10 @@ sub ParseData
 		}
 	}
 	close $ifd;
+
+	# If this is pg_type, auto-generate array types too.
+	GenerateArrayTypes($schema, $data) if $catname eq 'pg_type';
+
 	return $data;
 }
 
@@ -343,6 +356,63 @@ sub AddDefaultValues
 	}
 }
 
+# If a pg_type entry has an array_type_oid metadata field,
+# auto-generate an entry for its array type.
+sub GenerateArrayTypes
+{
+	my $pgtype_schema = shift;
+	my $types         = shift;
+	my @array_types;
+
+	foreach my $elem_type (@$types)
+	{
+		next if !(ref $elem_type eq 'HASH');
+		next if !defined($elem_type->{array_type_oid});
+
+		my %array_type;
+
+		# Set up metadata fields for array type.
+		$array_type{oid}           = $elem_type->{array_type_oid};
+		$array_type{autogenerated} = 1;
+		$array_type{line_number}   = $elem_type->{line_number};
+
+		# Set up column values derived from the element type.
+		$array_type{typname} = '_' . $elem_type->{typname};
+		$array_type{typelem} = $elem_type->{typname};
+
+		# Arrays require INT alignment, unless the element type requires
+		# DOUBLE alignment.
+		$array_type{typalign} = $elem_type->{typalign} eq 'd' ? 'd' : 'i';
+
+		# Fill in the rest of the array entry's fields.
+		foreach my $column (@$pgtype_schema)
+		{
+			my $attname = $column->{name};
+
+			# Skip if we already set it above.
+			next if defined $array_type{$attname};
+
+			# Apply the BKI_ARRAY_DEFAULT setting if there is one,
+			# otherwise copy the field from the element type.
+			if (defined $column->{array_default})
+			{
+				$array_type{$attname} = $column->{array_default};
+			}
+			else
+			{
+				$array_type{$attname} = $elem_type->{$attname};
+			}
+		}
+
+		# Lastly, cross-link the array to the element type.
+		$elem_type->{typarray} = $array_type{typname};
+
+		push @array_types, \%array_type;
+	}
+
+	push @$types, @array_types;
+}
+
 # Rename temporary files to final names.
 # Call this function with the final file name and the .tmp extension.
 #

src/backend/catalog/genbki.pl

@@ -394,7 +394,9 @@ EOM
 			next
 			  if $key eq "oid"
 			  || $key eq "oid_symbol"
+			  || $key eq "array_type_oid"
 			  || $key eq "descr"
+			  || $key eq "autogenerated"
 			  || $key eq "line_number";
 			die sprintf "unrecognized field name \"%s\" in %s.dat line %s\n",
 			  $key, $catname, $bki_values{line_number}