From fee45935eb7f5a098cbbbaf1c8d1a8f9a77ce418 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A9ter=20G=C3=B6m=C3=B6ri?= Date: Sat, 9 Jul 2016 17:21:27 +0200 Subject: Fix infinite loop in merl_transform This can happen when a syntactically incorrect text is passed to a merl:qquote/2,/3 call. The parse transform optimizes calls to some functions in merl by converting strings into templates at compile time. If this evaluation fails (in eval_call/4 - for example because of a sytanx error in the parsed text) the original function call should be kept unchanged. However in case of qquote/3 the call is converted into a combination of quote/2 and subst/2, but upon failure the original qquote/3 call is substituted into the wrong place. E.g.: this expression merl:qquote(Pos, Text, Env) is first converted to merl:subst(merl:quote(Pos, Text), Env) then if evaluating the quote call fails into merl:subst(merl:qquote(Pos, Text, Env), Env) and the expansion is run again on the internal qquote/3 argument resulting in an infinite loop. This is now fixed so in case of failure the original qquote/3 call is kept. --- lib/syntax_tools/test/merl_SUITE.erl | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) (limited to 'lib/syntax_tools/test') diff --git a/lib/syntax_tools/test/merl_SUITE.erl b/lib/syntax_tools/test/merl_SUITE.erl index 945972d405..52bbd9b3b8 100644 --- a/lib/syntax_tools/test/merl_SUITE.erl +++ b/lib/syntax_tools/test/merl_SUITE.erl @@ -29,12 +29,14 @@ init_per_group/2,end_per_group/2]). %% Test cases --export([merl_smoke_test/1]). +-export([merl_smoke_test/1, + transform_parse_error_test/1]). suite() -> [{ct_hooks,[ts_install_cth]}]. all() -> - [merl_smoke_test]. + [merl_smoke_test, + transform_parse_error_test]. groups() -> []. @@ -84,6 +86,21 @@ merl_smoke_test(Config) when is_list(Config) -> end)), ok. +transform_parse_error_test(_Config) -> + ?assertEqual("merl:quote(\"{\")", + f(merl_transform:parse_transform( + [?Q("merl:quote(\"{\")")], []))), + ?assertEqual("merl:quote(2, \"{\")", + f(merl_transform:parse_transform( + [?Q("merl:quote(2, \"{\")")], []))), + ?assertEqual("merl:qquote(\"{\", [{var, V}])", + f(merl_transform:parse_transform( + [?Q("merl:qquote(\"{\", [{var, V}])")], []))), + ?assertEqual("merl:qquote(2, \"{\", [{var, V}])", + f(merl_transform:parse_transform( + [?Q("merl:qquote(2, \"{\", [{var, V}])")], []))), + ok. + %% utilities f(Ts) when is_list(Ts) -> -- cgit v1.2.3