Backport BackgroundPsql perl test module

Backport the new BackgroundPsql modules and the constructor functions,
background_psql() and interactive_psql, to all supported
branches. That makes it easier to backpatch tests that use it.

BackgroundPsql was introduced in version 16. On version 16, this
commit backports just the new timeout argument from master (commit
334f512f45). On older branches, the whole facility. This includes the
change to `use warnings FATAL => 'all'`, which we haven't otherwise
backported, but it seems good to keep the file identical across
branches.

Discussion: https://www.postgresql.org/message-id/b7c64f20-ea01-4f15-9088-0cd6832af149@iki.fi

1 files changed, 50 insertions, 28 deletions

diff --git a/src/test/perl/PostgresNode.pm b/src/test/perl/PostgresNode.pm
index 8fae4eb1bb0..87bfa67eff8 100644
--- a/src/test/perl/PostgresNode.pm
+++ b/src/test/perl/PostgresNode.pm
@@ -101,6 +101,7 @@ use RecursiveCopy;
 use Socket;
 use Test::More;
 use TestLib ();
+use PostgreSQL::Test::BackgroundPsql ();
 use Time::HiRes qw(usleep);
 use Scalar::Util qw(blessed);
 
@@ -1627,18 +1628,9 @@ sub psql
 
 =pod
 
-=item $node->background_psql($dbname, \$stdin, \$stdout, $timer, %params) => harness
+=item $node->background_psql($dbname, %params) => PostgreSQL::Test::BackgroundPsql instance
 
-Invoke B<psql> on B<$dbname> and return an IPC::Run harness object, which the
-caller may use to send input to B<psql>.  The process's stdin is sourced from
-the $stdin scalar reference, and its stdout and stderr go to the $stdout
-scalar reference.  This allows the caller to act on other parts of the system
-while idling this backend.
-
-The specified timer object is attached to the harness, as well.  It's caller's
-responsibility to set the timeout length (usually
-$TestLib::timeout_default), and to restart the timer after
-each command if the timeout is per-command.
+Invoke B<psql> on B<$dbname> and return a BackgroundPsql object.
 
 psql is invoked in tuples-only unaligned mode with reading of B<.psqlrc>
 disabled.  That may be overridden by passing extra psql parameters.
@@ -1647,7 +1639,7 @@ Dies on failure to invoke psql, or if psql fails to connect.  Errors occurring
 later are the caller's problem.  psql runs with on_error_stop by default so
 that it will stop running sql and return 3 if passed SQL results in an error.
 
-Be sure to "finish" the harness when done with it.
+Be sure to "quit" the returned object when done with it.
 
 =over
 
@@ -1657,6 +1649,11 @@ By default, the B<psql> method invokes the B<psql> program with ON_ERROR_STOP=1
 set, so SQL execution is stopped at the first error and exit code 3 is
 returned.  Set B<on_error_stop> to 0 to ignore errors instead.
 
+=item timeout => 'interval'
+
+Set a timeout for a background psql session. By default, timeout of
+$PostgreSQL::Test::Utils::timeout_default is set up.
+
 =item replication => B<value>
 
 If set, add B<replication=value> to the conninfo string.
@@ -1673,12 +1670,13 @@ If given, it must be an array reference containing additional parameters to B<ps
 
 sub background_psql
 {
-	my ($self, $dbname, $stdin, $stdout, $timer, %params) = @_;
+	my ($self, $dbname, %params) = @_;
 
 	local $ENV{PGHOST} = $self->host;
 	local $ENV{PGPORT} = $self->port;
 
 	my $replication = $params{replication};
+	my $timeout = undef;
 
 	my @psql_params = (
 		'psql',
@@ -1690,30 +1688,54 @@ sub background_psql
 		'-');
 
 	$params{on_error_stop} = 1 unless defined $params{on_error_stop};
+	$timeout = $params{timeout} if defined $params{timeout};
 
 	push @psql_params, '-v', 'ON_ERROR_STOP=1' if $params{on_error_stop};
 	push @psql_params, @{ $params{extra_params} }
 	  if defined $params{extra_params};
 
-	# Ensure there is no data waiting to be sent:
-	$$stdin = "" if ref($stdin);
-	# IPC::Run would otherwise append to existing contents:
-	$$stdout = "" if ref($stdout);
+	return PostgreSQL::Test::BackgroundPsql->new(0, \@psql_params, $timeout);
+}
+
+=pod
+
+=item $node->interactive_psql($dbname, %params) => BackgroundPsql instance
+
+Invoke B<psql> on B<$dbname> and return a BackgroundPsql object, which the
+caller may use to send interactive input to B<psql>.
+
+A timeout of $PostgreSQL::Test::Utils::timeout_default is set up.
 
-	my $harness = IPC::Run::start \@psql_params,
-	  '<', $stdin, '>', $stdout, $timer;
+psql is invoked in tuples-only unaligned mode with reading of B<.psqlrc>
+disabled.  That may be overridden by passing extra psql parameters.
 
-	# Request some output, and pump until we see it.  This means that psql
-	# connection failures are caught here, relieving callers of the need to
-	# handle those.  (Right now, we have no particularly good handling for
-	# errors anyway, but that might be added later.)
-	my $banner = "background_psql: ready";
-	$$stdin = "\\echo $banner\n";
-	pump $harness until $$stdout =~ /$banner/ || $timer->is_expired;
+Dies on failure to invoke psql, or if psql fails to connect.
+Errors occurring later are the caller's problem.
 
-	die "psql startup timed out" if $timer->is_expired;
+Be sure to "quit" the returned object when done with it.
+
+=over
+
+=item extra_params => ['--single-transaction']
+
+If given, it must be an array reference containing additional parameters to B<psql>.
+
+=back
+
+This requires IO::Pty in addition to IPC::Run.
+
+=cut
+
+sub interactive_psql
+{
+	my ($self, $dbname, %params) = @_;
+
+	my @psql_params = ('psql', '-XAt', '-d', $self->connstr($dbname));
+
+	push @psql_params, @{ $params{extra_params} }
+	  if defined $params{extra_params};
 
-	return $harness;
+	return PostgreSQL::Test::BackgroundPsql->new(1, \@psql_params);
 }
 
 # Common sub of pgbench-invoking interfaces.  Makes any requested script files