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authorPéter Gömöri <[email protected]>2016-07-09 17:21:27 +0200
committerPéter Gömöri <[email protected]>2016-07-09 17:21:27 +0200
commitfee45935eb7f5a098cbbbaf1c8d1a8f9a77ce418 (patch)
treee5223681e9729194ed05c63eda92478a1c14d42d /lib/syntax_tools/test
parentca4000874a198b218fd62b90e842475d2a0bb8c7 (diff)
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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.
Diffstat (limited to 'lib/syntax_tools/test')
-rw-r--r--lib/syntax_tools/test/merl_SUITE.erl21
1 files changed, 19 insertions, 2 deletions
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) ->