File 1321-stdlib-Fix-a-loop-when-using-io_lib-option-chars_lim.patch of Package erlang
From 881d3be01d659b40861ad8058730f6cb6dc9a5f8 Mon Sep 17 00:00:00 2001
From: Hans Bolinder <hasse@erlang.org>
Date: Fri, 28 May 2021 07:20:46 +0200
Subject: [PATCH] stdlib: Fix a loop when using io_lib option 'chars_limit'
See GH-4824: https://github.com/erlang/otp/pull/4824.
The fix of ERL-967, see https://github.com/erlang/otp/issues/4307,
proved to be inaccurate.
Thanks to Hareen (kvsrh) for tracking down the bug. The fix in
https://github.com/erlang/otp/pull/4842 is included.
A clause that breaks the infinite loop is also added. It will hide
further bugs, but it is deemed more important not to loop.
---
lib/stdlib/src/io_lib_pretty.erl | 50 ++++++++++++++++++++++----------
lib/stdlib/test/io_SUITE.erl | 43 ++++++++++++++++++++++++---
2 files changed, 74 insertions(+), 19 deletions(-)
diff --git a/lib/stdlib/src/io_lib_pretty.erl b/lib/stdlib/src/io_lib_pretty.erl
index 77f02eafe0..32c5415067 100644
--- a/lib/stdlib/src/io_lib_pretty.erl
+++ b/lib/stdlib/src/io_lib_pretty.erl
@@ -448,11 +448,11 @@ intermediate(Term, D, T, RF, Enc, Str) when T > 0 ->
case If of
{_, Len, Dots, _} when Dots =:= 0; Len > T; D =:= 1 ->
If;
- _ ->
- find_upper(If, Term, T, D0, 2, D, RF, Enc, Str)
+ {_, Len, _, _} ->
+ find_upper(If, Term, T, D0, 2, D, RF, Enc, Str, Len)
end.
-find_upper(Lower, Term, T, Dl, Dd, D, RF, Enc, Str) ->
+find_upper(Lower, Term, T, Dl, Dd, D, RF, Enc, Str, LastLen) ->
Dd2 = Dd * 2,
D1 = case D < 0 of
true -> Dl + Dd2;
@@ -462,10 +462,11 @@ find_upper(Lower, Term, T, Dl, Dd, D, RF, Enc, Str) ->
case If of
{_, _, _Dots=0, _} -> % even if Len > T
If;
- {_, _Len=T, _, _} -> % increasing the depth is meaningless
+ {_, LastLen, _, _} ->
+ %% Cannot happen if print_length() is free of bugs.
If;
- {_, Len, _, _} when Len < T, D1 < D orelse D < 0 ->
- find_upper(If, Term, T, D1, Dd2, D, RF, Enc, Str);
+ {_, Len, _, _} when Len =< T, D1 < D orelse D < 0 ->
+ find_upper(If, Term, T, D1, Dd2, D, RF, Enc, Str, Len);
_ ->
search_depth(Lower, If, Term, T, Dl, D1, RF, Enc, Str)
end.
@@ -612,11 +613,15 @@ print_length_map_pairs(Term, D, D0, T, RF, Enc, Str) when D =:= 1; T =:= 0->
end,
{dots, 3, 3, More};
print_length_map_pairs({K, V, Iter}, D, D0, T, RF, Enc, Str) ->
- Pair1 = print_length_map_pair(K, V, D0, tsub(T, 1), RF, Enc, Str),
- {_, Len1, _, _} = Pair1,
Next = maps:next(Iter),
+ T1 = case Next =:= none of
+ false -> tsub(T, 1);
+ true -> T
+ end,
+ Pair1 = print_length_map_pair(K, V, D0, T1, RF, Enc, Str),
+ {_, Len1, _, _} = Pair1,
[Pair1 |
- print_length_map_pairs(Next, D - 1, D0, tsub(T, Len1+1), RF, Enc, Str)].
+ print_length_map_pairs(Next, D - 1, D0, tsub(T1, Len1), RF, Enc, Str)].
print_length_map_pair(K, V, D, T, RF, Enc, Str) ->
{_, KL, KD, _} = P1 = print_length(K, D, T, RF, Enc, Str),
@@ -641,7 +646,10 @@ print_length_tuple1(Tuple, I, D, T, RF, Enc, Str) when D =:= 1; T =:= 0->
{dots, 3, 3, More};
print_length_tuple1(Tuple, I, D, T, RF, Enc, Str) ->
E = element(I, Tuple),
- T1 = tsub(T, 1),
+ T1 = case I =:= tuple_size(Tuple) of
+ false -> tsub(T, 1);
+ true -> T
+ end,
{_, Len1, _, _} = Elem1 = print_length(E, D - 1, T1, RF, Enc, Str),
T2 = tsub(T1, Len1),
[Elem1 | print_length_tuple1(Tuple, I + 1, D - 1, T2, RF, Enc, Str)].
@@ -670,7 +678,10 @@ print_length_fields(Term, D, T, Tuple, I, RF, Enc, Str)
{dots, 3, 3, More};
print_length_fields([Def | Defs], D, T, Tuple, I, RF, Enc, Str) ->
E = element(I, Tuple),
- T1 = tsub(T, 1),
+ T1 = case I =:= tuple_size(Tuple) of
+ false -> tsub(T, 1);
+ true -> T
+ end,
Field1 = print_length_field(Def, D - 1, T1, E, RF, Enc, Str),
{_, Len1, _, _} = Field1,
T2 = tsub(T1, Len1),
@@ -695,8 +706,13 @@ print_length_list1(Term, D, T, RF, Enc, Str) when D =:= 1; T =:= 0->
More = fun(T1, Dd) -> ?FUNCTION_NAME(Term, D+Dd, T1, RF, Enc, Str) end,
{dots, 3, 3, More};
print_length_list1([E | Es], D, T, RF, Enc, Str) ->
- {_, Len1, _, _} = Elem1 = print_length(E, D - 1, tsub(T, 1), RF, Enc, Str),
- [Elem1 | print_length_list1(Es, D - 1, tsub(T, Len1 + 1), RF, Enc, Str)];
+ %% If E is the last element in list, don't account length for a comma.
+ T1 = case Es =:= [] of
+ false -> tsub(T, 1);
+ true -> T
+ end,
+ {_, Len1, _, _} = Elem1 = print_length(E, D - 1, T1, RF, Enc, Str),
+ [Elem1 | print_length_list1(Es, D - 1, tsub(T1, Len1), RF, Enc, Str)];
print_length_list1(E, D, T, RF, Enc, Str) ->
print_length(E, D - 1, T, RF, Enc, Str).
@@ -926,8 +942,12 @@ expand_list(Ifs, T, Dd, L0) ->
expand_list([], _T, _Dd) ->
[];
expand_list([If | Ifs], T, Dd) ->
- {_, Len1, _, _} = Elem1 = expand(If, tsub(T, 1), Dd),
- [Elem1 | expand_list(Ifs, tsub(T, Len1 + 1), Dd)];
+ T1 = case Ifs =:= [] of
+ false -> tsub(T, 1);
+ true -> T
+ end,
+ {_, Len1, _, _} = Elem1 = expand(If, T1, Dd),
+ [Elem1 | expand_list(Ifs, tsub(T1, Len1), Dd)];
expand_list({_, _, _, More}, T, Dd) ->
More(T, Dd).
diff --git a/lib/stdlib/test/io_SUITE.erl b/lib/stdlib/test/io_SUITE.erl
index 4eb5b1772c..025fcbc408 100644
--- a/lib/stdlib/test/io_SUITE.erl
+++ b/lib/stdlib/test/io_SUITE.erl
@@ -32,7 +32,8 @@
io_with_huge_message_queue/1, format_string/1, format_neg_zero/1,
maps/1, coverage/1, otp_14178_unicode_atoms/1, otp_14175/1,
otp_14285/1, limit_term/1, otp_14983/1, otp_15103/1, otp_15076/1,
- otp_15159/1, otp_15639/1, otp_15847/1, otp_15875/1]).
+ otp_15159/1, otp_15639/1, otp_15847/1, otp_15875/1,
+ chars_limit/1]).
-export([pretty/2, trf/3]).
@@ -65,7 +66,7 @@ all() ->
io_lib_width_too_small, io_with_huge_message_queue,
format_string, maps, coverage, otp_14178_unicode_atoms, otp_14175,
otp_14285, limit_term, otp_14983, otp_15103, otp_15076, otp_15159,
- otp_15639, otp_15847, otp_15875].
+ otp_15639, otp_15847, otp_15875, chars_limit].
%% Error cases for output.
error_1(Config) when is_list(Config) ->
@@ -2604,7 +2605,7 @@ trunc_depth(D, Fun) ->
"#{{...} => {...},...}" = Fun(M, D, 7),
"#{{[...],...} => {[...],...},...}" = Fun(M, D, 22),
"#{{[...],...} => {[...],...},[...] => [...]}" = Fun(M, D, 31),
- "#{{[...],...} => {[...],...},[...] => [...]}" = Fun(M, D, 33),
+ "#{{[...],...} => {[...],...},[1|...] => [...]}" = Fun(M, D, 33),
"#{{[1|...],[...]} => {[1|...],[...]},[1,2|...] => [...]}" =
Fun(M, D, 50),
@@ -2749,5 +2750,39 @@ otp_15847(_Config) ->
ok.
otp_15875(_Config) ->
+ %% This test is moot due to the fix in GH-4842.
S = io_lib:format("~tp", [[{0, [<<"00">>]}]], [{chars_limit, 18}]),
- "[{0,[<<48,...>>]}]" = lists:flatten(S).
+ "[{0,[<<\"00\">>]}]" = lists:flatten(S).
+
+%% GH-4824, GH-4842, OTP-17459.
+chars_limit(_Config) ->
+ List = fun R(I) ->
+ case I =:= 0 of true -> 0; false -> [I, R(I-1)] end
+ end,
+ Tuple = fun R(I) ->
+ case I =:= 0 of true -> 0; false -> {I, R(I-1)} end
+ end,
+ Map = fun R(I) ->
+ case I =:= 0 of true -> 0; false -> #{I => R(I-1)} end
+ end,
+ Record = fun R(I) ->
+ case I =:= 0 of true -> 0; false -> {b, R(I-1)} end
+ end,
+ Test = fun (F, N, Lim) ->
+ Opts = [{chars_limit, Lim},
+ {record_print_fun, fun rfd/2}],
+ [_|_] = io_lib_pretty:print(F(N), Opts)
+ end,
+ %% Used to loop:
+ Test(List, 1000, 1000),
+ Test(Tuple, 1000, 1000),
+ Test(Map, 1000, 1000),
+ Test(Record, 1000, 1000),
+
+ %% Misc sizes and char limits:
+ _ = [Test(What, N, CL) ||
+ N <- lists:seq(1, 50),
+ CL <- lists:seq(N, N*3),
+ What <- [List, Tuple, Map, Record]
+ ],
+ ok.
--
2.26.2
