Add \if support to pgbench

Patch adds \if to pgbench as it done for psql. Implementation shares condition
stack code with psql, so, this code is moved to fe_utils directory.

Author: Fabien COELHO with minor editorization by me
Review by: Vik Fearing, Fedor Sigaev
Discussion: https://www.postgresql.org/message-id/flat/alpine.DEB.2.20.1711252200190.28523@lancre

doc/src/sgml/ref/pgbench.sgml

@@ -900,6 +900,21 @@ pgbench <optional> <replaceable>options</replaceable> </optional> <replaceable>d
   </para>
 
   <variablelist>
+   <varlistentry>
+    <term><literal>\if</literal> <replaceable class="parameter">expression</replaceable></term>
+    <term><literal>\elif</literal> <replaceable class="parameter">expression</replaceable></term>
+    <term><literal>\else</literal></term>
+    <term><literal>\endif</literal></term>
+    <listitem>
+     <para> 
+      This group of commands implements nestable conditional blocks,
+      similarly to <literal>psql</literal>'s <xref linkend="psql-metacommand-if"/>.
+      Conditional expressions are identical to those with <literal>\set</literal>,
+      with non-zero values interpreted as true.
+     </para>
+    </listitem>
+   </varlistentry>
+
    <varlistentry id='pgbench-metacommand-set'>
     <term>
      <literal>\set <replaceable>varname</replaceable> <replaceable>expression</replaceable></literal>

doc/src/sgml/ref/psql-ref.sgml

@@ -2169,7 +2169,7 @@ hello 10
       </varlistentry>
 
 
-      <varlistentry>
+      <varlistentry id="psql-metacommand-if">
         <term><literal>\if</literal> <replaceable class="parameter">expression</replaceable></term>
         <term><literal>\elif</literal> <replaceable class="parameter">expression</replaceable></term>
         <term><literal>\else</literal></term>

src/bin/pgbench/t/001_pgbench_with_server.pl

@@ -264,6 +264,12 @@ pgbench(
 		qr{command=51.: int -7793829335365542153\b},
 		qr{command=52.: int -?\d+\b},
 		qr{command=53.: boolean true\b},
+		qr{command=65.: int 65\b},
+		qr{command=74.: int 74\b},
+		qr{command=83.: int 83\b},
+		qr{command=86.: int 86\b},
+		qr{command=93.: int 93\b},
+		qr{command=95.: int 0\b},
 	],
 	'pgbench expressions',
 	{   '001_pgbench_expressions' => q{-- integer functions
@@ -349,6 +355,41 @@ pgbench(
 \set v2 5432
 \set v3 -54.21E-2
 SELECT :v0, :v1, :v2, :v3;
+-- if tests
+\set nope 0
+\if 1 > 0
+\set id debug(65)
+\elif 0
+\set nope 1
+\else
+\set nope 1
+\endif
+\if 1 < 0
+\set nope 1
+\elif 1 > 0
+\set ie debug(74)
+\else
+\set nope 1
+\endif
+\if 1 < 0
+\set nope 1
+\elif 1 < 0
+\set nope 1
+\else
+\set if debug(83)
+\endif
+\if 1 = 1
+\set ig debug(86)
+\elif 0
+\set nope 1
+\endif
+\if 1 = 0
+\set nope 1
+\elif 1 <> 0
+\set ih debug(93)
+\endif
+-- must be zero if false branches where skipped
+\set nope debug(:nope)
 } });
 
 # backslash commands
@@ -396,7 +437,7 @@ SELECT LEAST(:i, :i, :i, :i, :i, :i, :i, :i, :i, :i, :i);
 
 	# SHELL
 	[   'shell bad command',               0,
-		[qr{meta-command 'shell' failed}], q{\shell no-such-command} ],
+		[qr{\(shell\) .* meta-command failed}], q{\shell no-such-command} ],
 	[   'shell undefined variable', 0,
 		[qr{undefined variable ":nosuchvariable"}],
 		q{-- undefined variable in shell

src/bin/pgbench/t/002_pgbench_no_server.pl

@@ -8,6 +8,16 @@ use warnings;
 use TestLib;
 use Test::More;
 
+# create a directory for scripts
+my $testname = $0;
+$testname =~ s,.*/,,;
+$testname =~ s/\.pl$//;
+
+my $testdir = "$TestLib::tmp_check/t_${testname}_stuff";
+mkdir $testdir
+	or
+	BAIL_OUT("could not create test directory \"${testdir}\": $!");
+
 # invoke pgbench
 sub pgbench
 {
@@ -17,6 +27,28 @@ sub pgbench
 		$stat, $out, $err, $name);
 }
 
+# invoke pgbench with scripts
+sub pgbench_scripts
+{
+	my ($opts, $stat, $out, $err, $name, $files) = @_;
+	my @cmd = ('pgbench', split /\s+/, $opts);
+	my @filenames = ();
+	if (defined $files)
+	{
+		for my $fn (sort keys %$files)
+		{
+			my $filename = $testdir . '/' . $fn;
+			# cleanup file weight if any
+			$filename =~ s/\@\d+$//;
+			# cleanup from prior runs
+			unlink $filename;
+			append_to_file($filename, $$files{$fn});
+			push @cmd, '-f', $filename;
+		}
+	}
+	command_checks_all(\@cmd, $stat, $out, $err, $name);
+}
+
 #
 # Option various errors
 #
@@ -125,4 +157,24 @@ pgbench(
 		qr{simple-update},              qr{select-only} ],
 	'pgbench builtin list');
 
+my @script_tests = (
+	# name, err, { file => contents }
+	[ 'missing endif', [qr{\\if without matching \\endif}], {'if-noendif.sql' => '\if 1'} ],
+	[ 'missing if on elif', [qr{\\elif without matching \\if}], {'elif-noif.sql' => '\elif 1'} ],
+	[ 'missing if on else', [qr{\\else without matching \\if}], {'else-noif.sql' => '\else'} ],
+	[ 'missing if on endif', [qr{\\endif without matching \\if}], {'endif-noif.sql' => '\endif'} ],
+	[ 'elif after else', [qr{\\elif after \\else}], {'else-elif.sql' => "\\if 1\n\\else\n\\elif 0\n\\endif"} ],
+	[ 'else after else', [qr{\\else after \\else}], {'else-else.sql' => "\\if 1\n\\else\n\\else\n\\endif"} ],
+	[ 'if syntax error', [qr{syntax error in command "if"}], {'if-bad.sql' => "\\if\n\\endif\n"} ],
+	[ 'elif syntax error', [qr{syntax error in command "elif"}], {'elif-bad.sql' => "\\if 0\n\\elif +\n\\endif\n"} ],
+	[ 'else syntax error', [qr{unexpected argument in command "else"}], {'else-bad.sql' => "\\if 0\n\\else BAD\n\\endif\n"} ],
+	[ 'endif syntax error', [qr{unexpected argument in command "endif"}], {'endif-bad.sql' => "\\if 0\n\\endif BAD\n"} ],
+);
+
+for my $t (@script_tests)
+{
+	my ($name, $err, $files) = @$t;
+	pgbench_scripts('', 1, [qr{^$}], $err, 'pgbench option error: ' . $name, $files);
+}
+
 done_testing();

src/bin/psql/Makefile

@@ -21,7 +21,7 @@ REFDOCDIR= $(top_srcdir)/doc/src/sgml/ref
 override CPPFLAGS := -I. -I$(srcdir) -I$(libpq_srcdir) $(CPPFLAGS)
 override LDFLAGS := -L$(top_builddir)/src/fe_utils -lpgfeutils $(libpq_pgport) $(LDFLAGS)
 
-OBJS=	command.o common.o conditional.o copy.o crosstabview.o \
+OBJS=	command.o common.o copy.o crosstabview.o \
 	describe.o help.o input.o large_obj.o mainloop.o \
 	prompt.o psqlscanslash.o sql_help.o startup.o stringutils.o \
 	tab-complete.o variables.o \

src/bin/psql/command.h

@@ -10,7 +10,7 @@
 
 #include "fe_utils/print.h"
 #include "fe_utils/psqlscan.h"
-#include "conditional.h"
+#include "fe_utils/conditional.h"
 
 
 typedef enum _backslashResult

src/bin/psql/prompt.h

@@ -10,7 +10,7 @@
 
 /* enum promptStatus_t is now defined by psqlscan.h */
 #include "fe_utils/psqlscan.h"
-#include "conditional.h"
+#include "fe_utils/conditional.h"
 
 char	   *get_prompt(promptStatus_t status, ConditionalStack cstack);
 

src/bin/psql/psqlscanslash.l

@@ -19,7 +19,7 @@
 #include "postgres_fe.h"
 
 #include "psqlscanslash.h"
-#include "conditional.h"
+#include "fe_utils/conditional.h"
 
 #include "libpq-fe.h"
 }

src/fe_utils/Makefile

@@ -19,7 +19,7 @@ include $(top_builddir)/src/Makefile.global
 
 override CPPFLAGS := -DFRONTEND -I$(libpq_srcdir) $(CPPFLAGS)
 
-OBJS = mbprint.o print.o psqlscan.o simple_list.o string_utils.o
+OBJS = mbprint.o print.o psqlscan.o simple_list.o string_utils.o conditional.o
 
 all: libpgfeutils.a
 

src/bin/psql/conditional.c → src/fe_utils/conditional.c

-/*
- * psql - the PostgreSQL interactive terminal
+/*-------------------------------------------------------------------------
+ * A stack of automaton states to handle nested conditionals.
  *
  * Copyright (c) 2000-2018, PostgreSQL Global Development Group
  *
- * src/bin/psql/conditional.c
+ * src/fe_utils/conditional.c
+ *
+ *-------------------------------------------------------------------------
  */
 #include "postgres_fe.h"
 
-#include "conditional.h"
+#include "fe_utils/conditional.h"
 
 /*
  * create stack
@@ -63,6 +65,27 @@ conditional_stack_pop(ConditionalStack cstack)
 	return true;
 }
 
+/*
+ * Returns current stack depth, for debugging purposes.
+ */
+int
+conditional_stack_depth(ConditionalStack cstack)
+{
+	if (cstack == NULL)
+		return -1;
+	else
+	{
+		IfStackElem	*p = cstack->head;
+		int			depth = 0;
+		while (p != NULL)
+		{
+			depth++;
+			p = p->next;
+		}
+		return depth;
+	}
+}
+
 /*
  * Fetch the current state of the top of the stack.
  */

src/bin/psql/conditional.h → src/include/fe_utils/conditional.h

-/*
- * psql - the PostgreSQL interactive terminal
+/*-------------------------------------------------------------------------
+ * A stack of automaton states to handle nested conditionals.
+ *
+ * This file describes a stack of automaton states which
+ * allow a manage nested conditionals.
+ *
+ * It is used by:
+ * - "psql" interpretor for handling \if ... \endif
+ * - "pgbench" interpretor for handling \if ... \endif
+ * - "pgbench" syntax checker to test for proper nesting
+ *
+ * The stack holds the state of enclosing conditionals (are we in
+ * a true branch? in a false branch? have we already encountered
+ * a true branch?) so that the interpreter knows whether to execute
+ * code and whether to evaluate conditions.
  *
  * Copyright (c) 2000-2018, PostgreSQL Global Development Group
  *
- * src/bin/psql/conditional.h
+ * src/include/fe_utils/conditional.h
+ *
+ *-------------------------------------------------------------------------
  */
 #ifndef CONDITIONAL_H
 #define CONDITIONAL_H
@@ -60,6 +75,8 @@ extern ConditionalStack conditional_stack_create(void);
 
 extern void conditional_stack_destroy(ConditionalStack cstack);
 
+extern int conditional_stack_depth(ConditionalStack cstack);
+
 extern void conditional_stack_push(ConditionalStack cstack, ifState new_state);
 
 extern bool conditional_stack_pop(ConditionalStack cstack);