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authorBjörn Gustavsson <[email protected]>2018-04-19 11:24:38 +0200
committerBjörn Gustavsson <[email protected]>2018-04-19 12:49:51 +0200
commitb5d657f176a440176eb073f749baadb7c45e19e4 (patch)
treef93e2edd9a0ee0b473c30064d51cffcf12e05875 /erts/emulator/test
parent0bcba3f1c9afc9a4164bf78641844a293768a7ec (diff)
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Make stacktraces consistent when backtrace_depth is 0
It is allowed to set the backtrace depth to 0, but when an exception is catched the stacktrace will still contain one element: 1> erlang:system_flag(backtrace_depth, 0). 8 2> catch error(badarg). {'EXIT',{badarg,[{shell,apply_fun,3, [{file,"shell.erl"},{line,908}]}]}} However, when an exception is raised using `erlang:raise/3`, there will be no elements in the stacktrace: 3> catch erlang:raise(error, badarg, [{fake,name,[arg],[]}]). {'EXIT',{badarg,[]}} Since the `error_handler` module uses `erlang:raise/3` to raise an exception when an undefined function is called, there will not be any stacktrace when calling an undefined function: 4> catch undef_module:undef_name(some_argument). {'EXIT',{undef,[]}} Fix this inconsistency by changing `erlang:raise/3` so that it always includes one element in the stacktrace: 3> catch erlang:raise(error, badarg, [{fake,name,[arg],[]}]). {'EXIT',{badarg,[{fake,name,[arg],[]}]}} 4> catch undef_module:undef_name(some_argument). {'EXIT',{undef,[{undef_module,undef_name,[some_argument],[]}]}}
Diffstat (limited to 'erts/emulator/test')
-rw-r--r--erts/emulator/test/exception_SUITE.erl56
1 files changed, 54 insertions, 2 deletions
diff --git a/erts/emulator/test/exception_SUITE.erl b/erts/emulator/test/exception_SUITE.erl
index da0292f385..60d14ce841 100644
--- a/erts/emulator/test/exception_SUITE.erl
+++ b/erts/emulator/test/exception_SUITE.erl
@@ -23,7 +23,8 @@
-export([all/0, suite/0,
badmatch/1, pending_errors/1, nil_arith/1, top_of_stacktrace/1,
stacktrace/1, nested_stacktrace/1, raise/1, gunilla/1, per/1,
- exception_with_heap_frag/1, line_numbers/1]).
+ exception_with_heap_frag/1, backtrace_depth/1,
+ line_numbers/1]).
-export([bad_guy/2]).
-export([crash/1]).
@@ -42,7 +43,7 @@ suite() ->
all() ->
[badmatch, pending_errors, nil_arith, top_of_stacktrace,
stacktrace, nested_stacktrace, raise, gunilla, per,
- exception_with_heap_frag, line_numbers].
+ exception_with_heap_frag, backtrace_depth, line_numbers].
-define(try_match(E),
catch ?MODULE:bar(),
@@ -572,6 +573,57 @@ do_exception_with_heap_frag(Bin, [Sz|Sizes]) ->
do_exception_with_heap_frag(Bin, Sizes);
do_exception_with_heap_frag(_, []) -> ok.
+backtrace_depth(Config) when is_list(Config) ->
+ _ = [do_backtrace_depth(D) || D <- lists:seq(0, 8)],
+ ok.
+
+do_backtrace_depth(D) ->
+ Old = erlang:system_flag(backtrace_depth, D),
+ try
+ Expected = max(1, D),
+ do_backtrace_depth_1(Expected)
+ after
+ _ = erlang:system_flag(backtrace_depth, Old)
+ end.
+
+do_backtrace_depth_1(D) ->
+ Exit = fun() ->
+ error(reason)
+ end,
+ HandCrafted = fun() ->
+ {'EXIT',{_,Stk0}} = (catch error(get_stacktrace)),
+ %% Fool the compiler to force a hand-crafted
+ %% stacktrace.
+ Stk = [hd(Stk0)|tl(Stk0)],
+ erlang:raise(error, reason, Stk)
+ end,
+ PassedOn = fun() ->
+ try error(get_stacktrace)
+ catch error:_:Stk ->
+ %% Just pass on the given stacktrace.
+ erlang:raise(error, reason, Stk)
+ end
+ end,
+ do_backtrace_depth_2(D, Exit),
+ do_backtrace_depth_2(D, HandCrafted),
+ do_backtrace_depth_2(D, PassedOn),
+ ok.
+
+do_backtrace_depth_2(D, Exc) ->
+ try
+ Exc()
+ catch
+ error:reason:Stk ->
+ if
+ length(Stk) =/= D ->
+ io:format("Expected depth: ~p\n", [D]),
+ io:format("~p\n", [Stk]),
+ error(bad_depth);
+ true ->
+ ok
+ end
+ end.
+
line_numbers(Config) when is_list(Config) ->
{'EXIT',{{case_clause,bad_tag},
[{?MODULE,line1,2,