From ba45e7939f010888ce29ecf8693e3e6f9a32d18e Mon Sep 17 00:00:00 2001
From: =?utf8?q?Vladim=C3=ADr=20=C4=8Cun=C3=A1t?= <vladimir.cunat@nic.cz>
Date: Wed, 7 Jul 2021 17:14:44 +0200
Subject: [PATCH] meson.build: add a simple sanity check of kres-gen result

---
 daemon/lua/meson.build | 32 ++++++++++++++++++++++++++++++++
 meson_options.txt      |  7 +++++++
 2 files changed, 39 insertions(+)

diff --git a/daemon/lua/meson.build b/daemon/lua/meson.build
index fabf0414b..f98fd631a 100644
--- a/daemon/lua/meson.build
+++ b/daemon/lua/meson.build
@@ -42,6 +42,38 @@ run_target(  # run manually to re-generate kres-gen.lua
   command: find_program('./kres-gen.sh'),
 )
 
+# A simple config test: check that sizes of some structures match
+# in C and pre-generated lua bindings.
+# The point is that regeneration is quite expensive in time and dependencies,
+# but this basic sanity check could be ran always.
+if get_option('kres_gen_test')
+  types_to_check = {
+	'time_t' : '#include <sys/time.h>',
+	'struct timeval' : '#include <sys/time.h>',
+	'zs_scanner_t' : '#include <libzscanner/scanner.h>',
+	'knot_pkt_t' : '#include <libknot/packet/pkt.h>',
+  }
+  # Construct the lua tester as a meson string.
+  kres_gen_test_luastr = '''
+	dofile('@0@')
+	local ffi = require('ffi')
+  '''.format(meson.current_source_dir() / 'kres-gen.lua')
+  foreach tname, tinclude: types_to_check
+	kres_gen_test_luastr += '''
+	  assert(ffi.sizeof(ffi.typeof('@0@')) == @1@,
+		'Lua binding for C type ' .. '@0@' .. ' has incorrect size: '
+		.. ffi.sizeof(ffi.typeof('@0@'))
+	  )
+	'''.format(tname, meson.get_compiler('c').sizeof(tname, prefix : tinclude))
+  endforeach
+  # Now feed it directly into luajit.
+  kres_gen_test = run_command(find_program('luajit'), '-e', kres_gen_test_luastr)
+  if kres_gen_test.returncode() != 0
+	error('if you use released Knot* versions, please contact us: https://www.knot-resolver.cz/contact/\n'
+		+ kres_gen_test.stderr().strip())
+  endif
+endif
+
 lua_src = [
   files('postconfig.lua'),
   files('kres.lua'),
diff --git a/meson_options.txt b/meson_options.txt
index f7ca06aab..572cd643d 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -175,6 +175,13 @@ option(
   description: 'html documentation dependencies and installation',
 )
 
+option(
+  'kres_gen_test',
+  type: 'boolean',
+  value: true,
+  description: 'run kres_gen_test: a simple sanity check for our lua bindings',
+)
+
 option(
   'config_tests',
   type: 'combo',
-- 
2.47.2