Fix a Yecc bug

A bug causing Yecc to generate badly formed parsers when encountering
very simple recursive rules has been fixed.

Thanks to Eric Pailleau for reporting the bug.

2 files changed, 39 insertions, 6 deletions

diff --git a/lib/parsetools/src/yecc.erl b/lib/parsetools/src/yecc.erl
index 53292b037a..f9207d926e 100644
--- a/lib/parsetools/src/yecc.erl
+++ b/lib/parsetools/src/yecc.erl
@@ -2106,8 +2106,8 @@ output_state_actions(St0, State, State, {Actions, Jump}, SI) ->
 output_state_actions(St, State, JState, _XActions, _SI) ->
     fwrite(St, <<"%% yeccpars2_~w: see yeccpars2_~w\n\n">>, [State, JState]).
 
-output_state_actions1(St, State, [], _IsFirst, normal, _SI) ->
-    output_state_actions_fini(State, St);
+output_state_actions1(St, State, [], IsFirst, normal, _SI) ->
+    output_state_actions_fini(State, IsFirst, St);
 output_state_actions1(St0, State, [], IsFirst, {to, ToS}, _SI) ->
     St = delim(St0, IsFirst),
     fwrite(St, 
@@ -2151,9 +2151,9 @@ output_call_to_includefile(NewState, St) ->
     fwrite(St, <<" yeccpars1(S, ~w, Ss, Stack, T, Ts, Tzr)">>, 
            [NewState]).
 
-output_state_actions_fini(State, St0) ->
+output_state_actions_fini(State, IsFirst, St0) ->
     %% Backward compatible.
-    St10 = delim(St0, false),
+    St10 = delim(St0, IsFirst),
     St = fwrite(St10, <<"yeccpars2_~w(_, _, _, _, T, _, _) ->\n">>, [State]),
     fwrite(St, <<" yeccerror(T).\n\n">>, []).
 
diff --git a/lib/parsetools/test/yecc_SUITE.erl b/lib/parsetools/test/yecc_SUITE.erl
index 3d66a2a525..9c865a1ec6 100644
--- a/lib/parsetools/test/yecc_SUITE.erl
+++ b/lib/parsetools/test/yecc_SUITE.erl
@@ -49,7 +49,7 @@
 	 
 	 otp_5369/1, otp_6362/1, otp_7945/1, otp_8483/1, otp_8486/1,
 	 
-	 otp_7292/1, otp_7969/1, otp_8919/1, otp_10302/1]).
+	 otp_7292/1, otp_7969/1, otp_8919/1, otp_10302/1, otp_11269/1]).
 
 % Default timetrap timeout (set in init_per_testcase).
 -define(default_timeout, ?t:minutes(1)).
@@ -76,7 +76,8 @@ groups() ->
       [empty, prec, yeccpre, lalr, old_yecc, other_examples]},
      {bugs, [],
       [otp_5369, otp_6362, otp_7945, otp_8483, otp_8486]},
-     {improvements, [], [otp_7292, otp_7969, otp_8919, otp_10302]}].
+     {improvements, [], [otp_7292, otp_7969, otp_8919, otp_10302,
+                         otp_11269]}].
 
 init_per_suite(Config) ->
     Config.
@@ -1963,6 +1964,38 @@ otp_10302(Config) when is_list(Config) ->
     run(Config, Ts),
     ok.
 
+otp_11269(doc) ->
+    "OTP-11269. A bug.";
+otp_11269(suite) -> [];
+otp_11269(Config) when is_list(Config) ->
+    Dir = ?privdir,
+    Filename = filename:join(Dir, "OTP-11269.yrl"),
+    Ret = [return, {report, false}],
+    Pai = <<"Nonterminals
+             list list0 list1 newline_list.
+
+             Terminals
+             '\n' semi.
+
+             Rootsymbol  list.
+
+             Endsymbol '$end'.
+
+             list ->   newline_list list0 : '$2'.
+
+             list0 -> list1 '\n' newline_list : '$1'.
+
+             list1 -> list1 semi newline_list list1 :
+                           {command_connect, '$1', '$4', semi}.
+
+             newline_list -> newline_list '\n' : nil.">>,
+    ok = file:write_file(Filename, Pai),
+    {ok,ErlFile,[{_YrlFile,[{none,yecc,{conflicts,1,0}}]}]} =
+        yecc:file(Filename, Ret),
+    Opts = [return, warn_unused_vars,{outdir,Dir}],
+    {ok,'OTP-11269',_Warnings} = compile:file(ErlFile, Opts),
+    ok.
+
 yeccpre_size() ->
     yeccpre_size(default_yeccpre()).