Merge branch 'raimo/triple-quoted-strings-warning' into maint

* raimo/triple-quoted-strings-warning:
  Update primary bootstrap
  Shorten code by list comprehension
  Update primary bootstrap
  Emit warning for triple quote chars
  Emit warning for triple quote chars

lib/stdlib/src/epp.erl

@@ -250,6 +250,8 @@ format_error({warning,Term}) ->
     io_lib:format("-warning(~tp).", [Term]);
 format_error(ftr_after_prefix) ->
     "feature directive not allowed after exports or record definitions";
+format_error(tqstring) ->
+    "Triple-quoted (or more) strings will change meaning in OTP-27.0";
 format_error(E) -> file:format_error(E).
 
 -spec scan_file(FileName, Options) ->
@@ -345,15 +347,32 @@ parse_file(Ifile, Options) ->
       WarningInfo :: warning_info().
 
 parse_file(Epp) ->
-    case parse_erl_form(Epp) of
-	{ok,Form} ->
-            [Form|parse_file(Epp)];
+    %% Code duplicated from parse_erl_form(Epp), but with
+    %% added search for tokens to warn for
+    case epp_request(Epp, scan_erl_form) of
+	{ok,Toks} ->
+            Warnings =
+                [{warning, {erl_anno:location(Anno),?MODULE,tqstring}}
+                 %% Warn about using 3 or more double qoutes
+                 || {tqstring,Anno,_} <- Toks],
+            case erl_parse:parse_form(Toks) of
+                {ok, Form} ->
+                    [Form|Warnings] ++ parse_file(Epp);
+                Problem2 ->
+                    parse_file_problem(Epp, Problem2, Warnings)
+            end;
+        Problem1 ->
+            parse_file_problem(Epp, Problem1, [])
+    end.
+
+parse_file_problem(Epp, Problem, Warnings) ->
+    case Problem of
 	{error,E} ->
-	    [{error,E}|parse_file(Epp)];
+	    [{error,E}|Warnings] ++ parse_file(Epp);
 	{warning,W} ->
-	    [{warning,W}|parse_file(Epp)];
+	    [{warning,W}|Warnings] ++ parse_file(Epp);
 	{eof,Location} ->
-	    [{eof,Location}]
+	    [{eof,Location}|Warnings]
     end.
 
 -spec default_encoding() -> source_encoding().

lib/stdlib/src/erl_parse.yrl

@@ -77,7 +77,7 @@ ssa_check_when_clause
 ssa_check_when_clauses.
 
 Terminals
-char integer float atom string var
+char integer float atom tqstring string var
 
 '(' ')' ',' '->' '{' '}' '[' ']' '|' '||' '<-' ';' ':' '#' '.'
 'after' 'begin' 'case' 'try' 'catch' 'end' 'fun' 'if' 'of' 'receive' 'when'
@@ -546,8 +546,11 @@ atomic -> atom : '$1'.
 atomic -> strings : '$1'.
 
 strings -> string : '$1'.
+strings -> tqstring : {string,?anno('$1'),element(3, '$1')}.
 strings -> string strings :
 	{string,?anno('$1'),element(3, '$1') ++ element(3, '$2')}.
+strings -> tqstring strings :
+	{string,?anno('$1'),element(3, '$1') ++ element(3, '$2')}.
 
 prefix_op -> '+' : '$1'.
 prefix_op -> '-' : '$1'.

lib/stdlib/src/erl_scan.erl

@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1996-2022. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2023. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -425,6 +425,12 @@ scan1("."=Cs, St, Line, Col, Toks) ->
     {more,{Cs,St,Col,Toks,Line,[],fun scan/6}};
 scan1([$.=C|Cs], St, Line, Col, Toks) ->
     scan_dot(Cs, St, Line, Col, Toks, [C]);
+scan1([$",$",$"|Cs], St, Line, Col, Toks) -> %" Emacs
+    scan_tqstring(Cs, St, Line, Col, Toks, 3); % Number of quote chars
+scan1([$",$"]=Cs, St, Line, Col, Toks) ->
+    {more,{Cs,St,Col,Toks,Line,[],fun scan/6}};
+scan1([$"]=Cs, St, Line, Col, Toks) -> %" Emacs
+    {more,{Cs,St,Col,Toks,Line,[],fun scan/6}};
 scan1([$"|Cs], St, Line, Col, Toks) -> %" Emacs
     State0 = {[],[],Line,Col},
     scan_string(Cs, St, Line, incr_column(Col, 1), Toks, State0);
@@ -828,6 +834,31 @@ scan_char([], St, Line, Col, Toks) ->
 scan_char(eof, _St, Line, Col, _Toks) ->
     scan_error(char, Line, Col, Line, incr_column(Col, 1), eof).
 
+%% Scan leading $" characters until we have them all
+%%
+scan_tqstring(Cs, St, Line, Col, Toks, Qs) ->
+    case Cs of
+        [$"|Ncs] ->
+            scan_tqstring(Ncs, St, Line, Col, Toks, Qs+1);
+        [] ->
+            {more, {[], St, Col, Toks, Line, Qs, fun scan_tqstring/6}};
+        _ ->
+            scan_tqstring_finish(Cs, St, Line, Col, Toks, Qs, tqstring)
+    end.
+
+scan_tqstring_finish(Cs, St, Line, Col, Toks, Qs, TokTag) when 1 < Qs ->
+    Anno = anno(Line, Col, St, ?STR(string, St, [$",$"])),
+    Tok = {TokTag, Anno, ""},
+    scan_tqstring_finish(
+      Cs, St, Line, incr_column(Col, 2), [Tok|Toks], Qs-2, string);
+scan_tqstring_finish(Cs, St, Line, Col, Toks, Qs, _TokTag) ->
+    Ncs =
+        case Qs of
+            1 -> [$"|Cs];%"
+            0 -> Cs
+        end,
+    scan1(Ncs, St, Line, Col, Toks).
+
 scan_string(Cs, #erl_scan{}=St, Line, Col, Toks, {Wcs,Str,Line0,Col0}) ->
     case scan_string0(Cs, St, Line, Col, $\", Str, Wcs) of %"
         {more,Ncs,Nline,Ncol,Nstr,Nwcs} ->

lib/stdlib/test/epp_SUITE.erl

@@ -1,7 +1,7 @@
 %%
 %% %CopyrightBegin%
 %%
-%% Copyright Ericsson AB 1998-2022. All Rights Reserved.
+%% Copyright Ericsson AB 1998-2023. All Rights Reserved.
 %%
 %% Licensed under the Apache License, Version 2.0 (the "License");
 %% you may not use this file except in compliance with the License.
@@ -30,6 +30,7 @@
          otp_11728/1, encoding/1, extends/1,  function_macro/1,
 	 test_error/1, test_warning/1, otp_14285/1,
 	 test_if/1,source_name/1,otp_16978/1,otp_16824/1,scan_file/1,file_macro/1,
+         triple_quotes_warning/1,
    deterministic_include/1, nondeterministic_include/1]).
 
 -export([epp_parse_erl_form/2]).
@@ -73,6 +74,7 @@ all() ->
      otp_8665, otp_8911, otp_10302, otp_10820, otp_11728,
      encoding, extends, function_macro, test_error, test_warning,
      otp_14285, test_if, source_name, otp_16978, otp_16824, scan_file, file_macro,
+     triple_quotes_warning,
      deterministic_include, nondeterministic_include].
 
 groups() ->
@@ -2055,6 +2057,73 @@ otp_16824(Config) when is_list(Config) ->
     [] = compile(Config, Cs),
     ok.
 
+triple_quotes_warning(Config) when is_list(Config) ->
+    Cs1 =
+        [{triple_quotes_warning_1,
+          <<"\n-doc \"foo\".\n">>,
+          []},
+         {triple_quotes_warning_2,
+          <<"\n-doc \"\" \"foo\" \"\".\n">>,
+          []},
+         {triple_quotes_warning_3,
+          <<"\n"
+            "-doc \"\"\"\n"
+            "    foo\n"
+            "    \"\"\".\n">>,
+          {warnings,[{{2,6},epp,tqstring}]}},
+         {triple_quotes_warning_4,
+          <<"\n"
+            "-doc  \"\"\"\"\n"
+            "      \"\"\"\".\n">>,
+          {warnings,
+           [{{2,7},epp,tqstring},
+            {{3,7},epp,tqstring}]}},
+         {triple_quotes_warning_5,
+          <<"\n"
+            "-doc   \"\"\"\"\"\n"
+            "       foo\n"
+            "       \"\"\"\"\".\n">>,
+          {warnings,
+           [{{2,8},epp,tqstring},
+            {{4,9},epp,tqstring}]}}
+        ],
+    [] = compile(Config, Cs1),
+
+    Cs2 =
+        [{triple_quotes_warning_10,
+          <<"\n"
+            "-export([foo/0]).\n"
+            "foo() ->\n"
+            "    \"\"\"\n"
+            "    bar\n"
+            "    \"\"\".\n">>,
+          {warnings,[{{4,5},epp,tqstring}]}},
+         {triple_quotes_warning_11,
+          <<"\n"
+            "-export([foo/0]).\n"
+            "foo() ->\n"
+            "    \"\"\"\"\n"
+            "    ++ lists:duplicate(4, $x) ++\n"
+            "    \"\"\"\".\n">>,
+          {warnings,
+           [{{4,5},epp,tqstring},
+            {{6,5},epp,tqstring}]}},
+         {triple_quotes_warning_12,
+          <<"\n"
+            "-export([foo/0]).\n"
+            "foo() ->\n"
+            "    \"\"\"\"\"\n"
+            "    bar\n"
+            "    \"\"\"\"\".\n">>,
+          {warnings,
+           [{{4,5},epp,tqstring},
+            {{6,6},epp,tqstring}]}} ],
+    [] = compile(Config, Cs2),
+
+    ok.
+
+
+
 %% Start location is 1.
 check(Config, Tests) ->
     eval_tests(Config, fun check_test/3, Tests).
@@ -2085,6 +2154,8 @@ eval_tests(Config, Fun, Tests) ->
                         case E of
                             {errors, Errors} ->
                                 call_format_error(Errors);
+                            {warnings, Errors} ->
+                                call_format_error(Errors);
                             _ ->
                                 ok
                         end,