diff options
| -rw-r--r-- | erts/doc/src/erlang.xml | 28 | ||||
| -rw-r--r-- | lib/compiler/doc/src/compile.xml | 8 | ||||
| -rw-r--r-- | lib/stdlib/src/erl_lint.erl | 73 | ||||
| -rw-r--r-- | lib/stdlib/test/erl_lint_SUITE.erl | 63 |
4 files changed, 158 insertions, 14 deletions
diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml index 6f70ae4a52..6d165e9eff 100644 --- a/erts/doc/src/erlang.xml +++ b/erts/doc/src/erlang.xml @@ -1813,8 +1813,9 @@ true</pre> <fsummary>Get the call stack back-trace of the last exception.</fsummary> <type name="stack_item"/> <desc> - <p>Gets the call stack back-trace (<em>stacktrace</em>) of the - last exception in the calling process as a list of + <p>Gets the call stack back-trace (<em>stacktrace</em>) for an + exception that has just been caught + in the calling process as a list of <c>{<anno>Module</anno>,<anno>Function</anno>,<anno>Arity</anno>,<anno>Location</anno>}</c> tuples. Field <c><anno>Arity</anno></c> in the first tuple can be the argument list of that function call instead of an arity integer, @@ -1822,6 +1823,29 @@ true</pre> <p>If there has not been any exceptions in a process, the stacktrace is <c>[]</c>. After a code change for the process, the stacktrace can also be reset to <c>[]</c>.</p> + <p><c>erlang:get_stacktrace/0</c> is only guaranteed to return + a stacktrace if called (directly or indirectly) from within the + scope of a <c>try</c> expression. That is, the following call works:</p> +<pre> +try Expr +catch + C:R -> + {C,R,erlang:get_stacktrace()} +end</pre> + <p>As does this call:</p> +<pre> +try Expr +catch + C:R -> + {C,R,helper()} +end + +helper() -> + erlang:get_stacktrace().</pre> + + <warning><p>In a future release, + <c>erlang:get_stacktrace/0</c> will return <c>[]</c> if called + from outside a <c>try</c> expression.</p></warning> <p>The stacktrace is the same data as operator <c>catch</c> returns, for example:</p> <pre> diff --git a/lib/compiler/doc/src/compile.xml b/lib/compiler/doc/src/compile.xml index fed68037c1..10164890f2 100644 --- a/lib/compiler/doc/src/compile.xml +++ b/lib/compiler/doc/src/compile.xml @@ -629,6 +629,14 @@ module.beam: module.erl \ <p>Turns off warnings for unused record types. Default is to emit warnings for unused locally defined record types.</p> </item> + + <tag><c>nowarn_get_stacktrace</c></tag> + <item> + <p>Turns off warnings for using <c>get_stacktrace/0</c> in a context + where it will probably not work in a future release. For example, + by default there will be a warning if <c>get_stacktrace/0</c> is + used following a <c>catch</c> expression.</p> + </item> </taglist> <p>Another class of warnings is generated by the compiler diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl index 7c40058dd8..d53a31db0d 100644 --- a/lib/stdlib/src/erl_lint.erl +++ b/lib/stdlib/src/erl_lint.erl @@ -92,6 +92,14 @@ value_option(Flag, Default, On, OnVal, Off, OffVal, Opts) -> :: dict:dict(ta(), line()) }). + +%% Are we outside or inside a catch or try/catch? +-type catch_scope() :: 'none' + | 'after_old_catch' + | 'after_try' + | 'wrong_part_of_try' + | 'try_catch'. + %% Define the lint state record. %% 'called' and 'exports' contain {Line, {Function, Arity}}, %% the other function collections contain {Function, Arity}. @@ -135,7 +143,9 @@ value_option(Flag, Default, On, OnVal, Off, OffVal, Opts) -> types = dict:new() %Type definitions :: dict:dict(ta(), #typeinfo{}), exp_types=gb_sets:empty() %Exported types - :: gb_sets:set(ta()) + :: gb_sets:set(ta()), + catch_scope = none %Inside/outside try or catch + :: catch_scope() }). -type lint_state() :: #lint{}. @@ -223,7 +233,15 @@ format_error({redefine_old_bif_import,{F,A}}) -> format_error({redefine_bif_import,{F,A}}) -> io_lib:format("import directive overrides auto-imported BIF ~w/~w~n" " - use \"-compile({no_auto_import,[~w/~w]}).\" to resolve name clash", [F,A,F,A]); - +format_error({get_stacktrace,wrong_part_of_try}) -> + "erlang:get_stacktrace/0 used in the wrong part of 'try' expression. " + "(Use it in the block between 'catch' and 'end'.)"; +format_error({get_stacktrace,after_old_catch}) -> + "erlang:get_stacktrace/0 used following an old-style 'catch' " + "may stop working in a future release. (Use it inside 'try'.)"; +format_error({get_stacktrace,after_try}) -> + "erlang:get_stacktrace/0 used following a 'try' expression " + "may stop working in a future release. (Use it inside 'try'.)"; format_error({deprecated, MFA, ReplacementMFA, Rel}) -> io_lib:format("~s is deprecated and will be removed in ~s; use ~s", [format_mfa(MFA), Rel, format_mfa(ReplacementMFA)]); @@ -568,7 +586,10 @@ start(File, Opts) -> false, Opts)}, {missing_spec_all, bool_option(warn_missing_spec_all, nowarn_missing_spec_all, - false, Opts)} + false, Opts)}, + {get_stacktrace, + bool_option(warn_get_stacktrace, nowarn_get_stacktrace, + true, Opts)} ], Enabled1 = [Category || {Category,true} <- Enabled0], Enabled = ordsets:from_list(Enabled1), @@ -1405,8 +1426,9 @@ call_function(Line, F, A, #lint{usage=Usage0,called=Cd,func=Func,file=File}=St) %% function(Line, Name, Arity, Clauses, State) -> State. function(Line, Name, Arity, Cs, St0) -> - St1 = define_function(Line, Name, Arity, St0#lint{func={Name,Arity}}), - clauses(Cs, St1). + St1 = St0#lint{func={Name,Arity},catch_scope=none}, + St2 = define_function(Line, Name, Arity, St1), + clauses(Cs, St2). -spec define_function(line(), atom(), arity(), lint_state()) -> lint_state(). @@ -2338,22 +2360,24 @@ expr({call,Line,F,As}, Vt, St0) -> expr({'try',Line,Es,Scs,Ccs,As}, Vt, St0) -> %% Currently, we don't allow any exports because later %% passes cannot handle exports in combination with 'after'. - {Evt0,St1} = exprs(Es, Vt, St0), + {Evt0,St1} = exprs(Es, Vt, St0#lint{catch_scope=wrong_part_of_try}), TryLine = {'try',Line}, Uvt = vtunsafe(TryLine, Evt0, Vt), Evt1 = vtupdate(Uvt, Evt0), - {Sccs,St2} = icrt_clauses(Scs++Ccs, TryLine, vtupdate(Evt1, Vt), St1), + {Sccs,St2} = try_clauses(Scs, Ccs, TryLine, + vtupdate(Evt1, Vt), St1), Rvt0 = Sccs, Rvt1 = vtupdate(vtunsafe(TryLine, Rvt0, Vt), Rvt0), Evt2 = vtmerge(Evt1, Rvt1), {Avt0,St} = exprs(As, vtupdate(Evt2, Vt), St2), Avt1 = vtupdate(vtunsafe(TryLine, Avt0, Vt), Avt0), Avt = vtmerge(Evt2, Avt1), - {Avt,St}; + {Avt,St#lint{catch_scope=after_try}}; expr({'catch',Line,E}, Vt, St0) -> %% No new variables added, flag new variables as unsafe. {Evt,St} = expr(E, Vt, St0), - {vtupdate(vtunsafe({'catch',Line}, Evt, Vt), Evt),St}; + {vtupdate(vtunsafe({'catch',Line}, Evt, Vt), Evt), + St#lint{catch_scope=after_old_catch}}; expr({match,_Line,P,E}, Vt, St0) -> {Evt,St1} = expr(E, Vt, St0), {Pvt,Bvt,St2} = pattern(P, vtupdate(Evt, Vt), St1), @@ -3173,6 +3197,17 @@ is_module_dialyzer_option(Option) -> error_handling,race_conditions,no_missing_calls, specdiffs,overspecs,underspecs,unknown]). +%% try_catch_clauses(Scs, Ccs, In, ImportVarTable, State) -> +%% {UpdVt,State}. + +try_clauses(Scs, Ccs, In, Vt, St0) -> + {Csvt0,St1} = icrt_clauses(Scs, Vt, St0), + St2 = St1#lint{catch_scope=try_catch}, + {Csvt1,St3} = icrt_clauses(Ccs, Vt, St2), + Csvt = Csvt0 ++ Csvt1, + UpdVt = icrt_export(Csvt, Vt, In, St3), + {UpdVt,St3}. + %% icrt_clauses(Clauses, In, ImportVarTable, State) -> %% {UpdVt,State}. @@ -3657,7 +3692,8 @@ has_wildcard_field([]) -> false. check_remote_function(Line, M, F, As, St0) -> St1 = deprecated_function(Line, M, F, As, St0), St2 = check_qlc_hrl(Line, M, F, As, St1), - format_function(Line, M, F, As, St2). + St3 = check_get_stacktrace(Line, M, F, As, St2), + format_function(Line, M, F, As, St3). %% check_qlc_hrl(Line, ModName, FuncName, [Arg], State) -> State %% Add warning if qlc:q/1,2 has been called but qlc.hrl has not @@ -3706,6 +3742,23 @@ deprecated_function(Line, M, F, As, St) -> St end. +check_get_stacktrace(Line, erlang, get_stacktrace, [], St) -> + case St of + #lint{catch_scope=none} -> + St; + #lint{catch_scope=try_catch} -> + St; + #lint{catch_scope=Scope} -> + case is_warn_enabled(get_stacktrace, St) of + false -> + St; + true -> + add_warning(Line, {get_stacktrace,Scope}, St) + end + end; +check_get_stacktrace(_, _, _, _, St) -> + St. + -dialyzer({no_match, deprecated_type/5}). deprecated_type(L, M, N, As, St) -> diff --git a/lib/stdlib/test/erl_lint_SUITE.erl b/lib/stdlib/test/erl_lint_SUITE.erl index 03cad2c093..02524679fa 100644 --- a/lib/stdlib/test/erl_lint_SUITE.erl +++ b/lib/stdlib/test/erl_lint_SUITE.erl @@ -65,7 +65,8 @@ maps/1,maps_type/1,maps_parallel_match/1, otp_11851/1,otp_11879/1,otp_13230/1, record_errors/1, otp_11879_cont/1, - non_latin1_module/1, otp_14323/1]). + non_latin1_module/1, otp_14323/1, + get_stacktrace/1]). suite() -> [{ct_hooks,[ts_install_cth]}, @@ -85,7 +86,8 @@ all() -> too_many_arguments, basic_errors, bin_syntax_errors, predef, maps, maps_type, maps_parallel_match, otp_11851, otp_11879, otp_13230, - record_errors, otp_11879_cont, non_latin1_module, otp_14323]. + record_errors, otp_11879_cont, non_latin1_module, otp_14323, + get_stacktrace]. groups() -> [{unused_vars_warn, [], @@ -3980,6 +3982,63 @@ otp_14323(Config) -> [] = run(Config, Ts), ok. +get_stacktrace(Config) -> + Ts = [{old_catch, + <<"t1() -> + catch error(foo), + erlang:get_stacktrace(). + ">>, + [], + {warnings,[{3,erl_lint,{get_stacktrace,after_old_catch}}]}}, + {nowarn_get_stacktrace, + <<"t1() -> + catch error(foo), + erlang:get_stacktrace(). + ">>, + [nowarn_get_stacktrace], + []}, + {try_catch, + <<"t1(X) -> + try abs(X) of + _ -> + erlang:get_stacktrace() + catch + _:_ -> ok + end. + + t2() -> + try error(foo) + catch _:_ -> ok + end, + erlang:get_stacktrace(). + + t3() -> + try error(foo) + catch _:_ -> + try error(bar) + catch _:_ -> + ok + end, + erlang:get_stacktrace() + end. + + no_warning(X) -> + try + abs(X) + catch + _:_ -> + erlang:get_stacktrace() + end. + ">>, + [], + {warnings,[{4,erl_lint,{get_stacktrace,wrong_part_of_try}}, + {13,erl_lint,{get_stacktrace,after_try}}, + {22,erl_lint,{get_stacktrace,after_try}}]}}], + + run(Config, Ts), + ok. + + run(Config, Tests) -> F = fun({N,P,Ws,E}, BadL) -> case catch run_test(Config, P, Ws) of |