File 0228-stdlib-Correct-evaluation-of-bitstring-com... of Package erlang

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File 0228-stdlib-Correct-evaluation-of-bitstring-comprehension.patch of Package erlang

From 5a356a6bf3f65f9b1bbdcafe7068647f240eef49 Mon Sep 17 00:00:00 2001
From: Hans Bolinder <hasse@erlang.org>
Date: Wed, 7 Oct 2020 13:16:55 +0200
Subject: [PATCH 1/2] stdlib: Correct evaluation of bitstring comprehension

If the Size expression cannot be evaluated, the binary pattern does
not match.
---
 lib/stdlib/src/eval_bits.erl       | 23 +++++++++++++++--------
 lib/stdlib/test/erl_eval_SUITE.erl | 11 +++++++++--
 2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/lib/stdlib/src/eval_bits.erl b/lib/stdlib/src/eval_bits.erl
index 5c75320de0..157d823a09 100644
--- a/lib/stdlib/src/eval_bits.erl
+++ b/lib/stdlib/src/eval_bits.erl
@@ -198,20 +198,27 @@ bin_gen_field({bin_element,Line,{string,SLine,S},Size0,Options0},
               Bin0, Bs0, BBs0, Mfun, Efun) ->
     {Size1, [Type,{unit,Unit},Sign,Endian]} =
         make_bit_type(Line, Size0, Options0),
-    {value, Size, _BBs} = Efun(Size1, BBs0),
-    F = fun(C, Bin, Bs, BBs) ->
-                bin_gen_field1(Bin, Type, Size, Unit, Sign, Endian,
-                               {integer,SLine,C}, Bs, BBs, Mfun)
-        end,
-    bin_gen_field_string(S, Bin0, Bs0, BBs0, F);
+    case catch Efun(Size1, BBs0) of
+        {value, Size, _BBs} -> % 
+            F = fun(C, Bin, Bs, BBs) ->
+                        bin_gen_field1(Bin, Type, Size, Unit, Sign, Endian,
+                                       {integer,SLine,C}, Bs, BBs, Mfun)
+                end,
+            bin_gen_field_string(S, Bin0, Bs0, BBs0, F)
+    end;
 bin_gen_field({bin_element,Line,VE,Size0,Options0}, 
               Bin, Bs0, BBs0, Mfun, Efun) ->
     {Size1, [Type,{unit,Unit},Sign,Endian]} = 
         make_bit_type(Line, Size0, Options0),
     V = erl_eval:partial_eval(VE),
     NewV = coerce_to_float(V, Type),
-    {value, Size, _BBs} = Efun(Size1, BBs0),
-    bin_gen_field1(Bin, Type, Size, Unit, Sign, Endian, NewV, Bs0, BBs0, Mfun).
+    case catch Efun(Size1, BBs0) of
+        {value, Size, _BBs} ->
+            bin_gen_field1(Bin, Type, Size, Unit, Sign, Endian,
+                           NewV, Bs0, BBs0, Mfun);
+        _ ->
+            done
+    end.
 
 bin_gen_field_string([], Rest, Bs, BBs, _F) ->
     {match,Bs,BBs,Rest};
diff --git a/lib/stdlib/test/erl_eval_SUITE.erl b/lib/stdlib/test/erl_eval_SUITE.erl
index a29b60cd1d..392e52bdb1 100644
--- a/lib/stdlib/test/erl_eval_SUITE.erl
+++ b/lib/stdlib/test/erl_eval_SUITE.erl
@@ -51,7 +51,8 @@
          otp_15035/1,
          otp_16439/1,
          otp_14708/1,
-         otp_16545/1]).
+         otp_16545/1,
+         otp_16865/1]).
 
 %%
 %% Define to run outside of test server
@@ -91,7 +92,7 @@ all() ->
      otp_6539, otp_6543, otp_6787, otp_6977, otp_7550,
      otp_8133, otp_10622, otp_13228, otp_14826,
      funs, try_catch, eval_expr_5, zero_width,
-     eep37, eep43, otp_15035, otp_16439, otp_14708, otp_16545].
+     eep37, eep43, otp_15035, otp_16439, otp_14708, otp_16545, otp_16865].
 
 groups() -> 
     [].
@@ -1745,6 +1746,12 @@ otp_16545(Config) when is_list(Config) ->
     error_check("<<\"\":problem/signed>>.", badarg),
     ok.
 
+otp_16865(Config) when is_list(Config) ->
+    check(fun() -> << <<>> || <<34:(1/0)>> <= <<"string">> >> end,
+          "<< <<>> || <<34:(1/0)>> <= <<\"string\">> >>.",
+          <<>>),
+    ok.
+
 %% Check the string in different contexts: as is; in fun; from compiled code.
 check(F, String, Result) ->
     check1(F, String, Result),
-- 
2.26.2

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