From 6e93fb788aebb9050da2166749b41ff54197e049 Mon Sep 17 00:00:00 2001 From: Kostis Sagonas Date: Thu, 7 May 2015 14:43:02 +0200 Subject: Take out automatic insertion of 'undefined' from typed record fields Background ----------- In record fields with a type declaration but without an initializer, the Erlang parser inserted automatically the singleton type 'undefined' to the list of declared types, if that value was not present there. I.e. the record declaration: -record(rec, {f1 :: float(), f2 = 42 :: integer(), f3 :: some_mod:some_typ()}). was translated by the parser to: -record(rec, {f1 :: float() | 'undefined', f2 = 42 :: integer(), f3 :: some_mod:some_typ() | 'undefined'}). The rationale for this was that creation of a "dummy" #rec{} record should not result in a warning from dialyzer that e.g. the implicit initialization of the #rec.f1 field violates its type declaration. Problems --------- This seemingly innocent action has some unforeseen consequences. For starters, there is no way for programmers to declare that e.g. only floats make sense for the f1 field of #rec{} records when there is no `obvious' default initializer for this field. (This also affects tools like PropEr that use these declarations produced by the Erlang parser to generate random instances of records for testing purposes.) It also means that dialyzer does not warn if e.g. an is_atom/1 test or something more exotic like an atom_to_list/1 call is performed on the value of the f1 field. Similarly, there is no way to extend dialyzer to warn if it finds record constructions where f1 is not initialized to some float. Last but not least, it is semantically problematic when the type of the field is an opaque type: creating a union of an opaque and a structured type is very problematic for analysis because it fundamentally breaks the opacity of the term at that point. Change ------- To solve these problems the parser will not automatically insert the 'undefined' value anymore; instead the user has the option to choose the places where this value makes sense (for the field) and where it does not and insert the | 'undefined' there manually. Consequences of this change ---------------------------- This change means that dialyzer will issue a warning for all places where records with uninitialized fields are created and those fields have a declared type that is incompatible with 'undefined' (e.g. float()). This warning can be suppressed easily by adding | 'undefined' to the type of this field. This also adds documentation that the user really intends to create records where this field is uninitialized. --- lib/stdlib/src/erl_parse.yrl | 22 +--------------------- 1 file changed, 1 insertion(+), 21 deletions(-) (limited to 'lib/stdlib/src') diff --git a/lib/stdlib/src/erl_parse.yrl b/lib/stdlib/src/erl_parse.yrl index 206b0c6e7b..ae42a8f0b1 100644 --- a/lib/stdlib/src/erl_parse.yrl +++ b/lib/stdlib/src/erl_parse.yrl @@ -790,31 +790,11 @@ record_fields([{match,_Am,{atom,Aa,A},Expr}|Fields]) -> [{record_field,Aa,{atom,Aa,A},Expr}|record_fields(Fields)]; record_fields([{typed,Expr,TypeInfo}|Fields]) -> [Field] = record_fields([Expr]), - TypeInfo1 = - case Expr of - {match, _, _, _} -> TypeInfo; %% If we have an initializer. - {atom, Aa, _} -> - case has_undefined(TypeInfo) of - false -> - lift_unions(abstract2(undefined, Aa), TypeInfo); - true -> - TypeInfo - end - end, - [{typed_record_field,Field,TypeInfo1}|record_fields(Fields)]; + [{typed_record_field,Field,TypeInfo}|record_fields(Fields)]; record_fields([Other|_Fields]) -> ret_err(?anno(Other), "bad record field"); record_fields([]) -> []. -has_undefined({atom,_,undefined}) -> - true; -has_undefined({ann_type,_,[_,T]}) -> - has_undefined(T); -has_undefined({type,_,union,Ts}) -> - lists:any(fun has_undefined/1, Ts); -has_undefined(_) -> - false. - term(Expr) -> try normalise(Expr) catch _:_R -> ret_err(?anno(Expr), "bad attribute") -- cgit v1.2.3 From 3224c9b0b7022ccf2483af95f4efd8a6b6234f47 Mon Sep 17 00:00:00 2001 From: Hans Bolinder Date: Tue, 6 Oct 2015 15:08:57 +0200 Subject: Update Kernel and STDLIB Record field types have been modified due to commit 8ce35b2: "Take out automatic insertion of 'undefined' from typed record fields". --- lib/stdlib/src/beam_lib.erl | 2 +- lib/stdlib/src/epp.erl | 3 ++- lib/stdlib/src/escript.erl | 8 ++++---- lib/stdlib/src/supervisor.erl | 10 +++++----- 4 files changed, 12 insertions(+), 11 deletions(-) (limited to 'lib/stdlib/src') diff --git a/lib/stdlib/src/beam_lib.erl b/lib/stdlib/src/beam_lib.erl index b93ce97cd3..cb19fe4175 100644 --- a/lib/stdlib/src/beam_lib.erl +++ b/lib/stdlib/src/beam_lib.erl @@ -867,7 +867,7 @@ mandatory_chunks() -> %%% can use it. %%% ==================================================================== --record(state, {crypto_key_f :: crypto_fun()}). +-record(state, {crypto_key_f :: crypto_fun() | 'undefined'}). -define(CRYPTO_KEY_SERVER, beam_lib__crypto_key_server). diff --git a/lib/stdlib/src/epp.erl b/lib/stdlib/src/epp.erl index d3124ac593..c8bba579cc 100644 --- a/lib/stdlib/src/epp.erl +++ b/lib/stdlib/src/epp.erl @@ -49,7 +49,8 @@ -define(DEFAULT_ENCODING, utf8). %% Epp state record. --record(epp, {file :: file:io_device(), %Current file +-record(epp, {file :: file:io_device() + | 'undefined', %Current file location=1, %Current location delta=0 :: non_neg_integer(), %Offset from Location (-file) name="" :: file:name(), %Current file name diff --git a/lib/stdlib/src/escript.erl b/lib/stdlib/src/escript.erl index 41b49f4a86..b8ce311c35 100644 --- a/lib/stdlib/src/escript.erl +++ b/lib/stdlib/src/escript.erl @@ -38,7 +38,7 @@ -record(state, {file :: file:filename(), module :: module(), forms_or_bin, - source :: source(), + source :: source() | 'undefined', n_errors :: non_neg_integer(), mode :: mode(), exports_main :: boolean(), @@ -49,9 +49,9 @@ -type emu_args() :: string(). -record(sections, {type, - shebang :: shebang(), - comment :: comment(), - emu_args :: emu_args(), + shebang :: shebang() | 'undefined', + comment :: comment() | 'undefined', + emu_args :: emu_args() | 'undefined', body}). -record(extract_options, {compile_source}). diff --git a/lib/stdlib/src/supervisor.erl b/lib/stdlib/src/supervisor.erl index 92a0c29011..142aaa8688 100644 --- a/lib/stdlib/src/supervisor.erl +++ b/lib/stdlib/src/supervisor.erl @@ -1,7 +1,7 @@ %% %% %CopyrightBegin% %% -%% Copyright Ericsson AB 1996-2014. All Rights Reserved. +%% Copyright Ericsson AB 1996-2015. 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. @@ -107,11 +107,11 @@ -define(SET, sets:set). -record(state, {name, - strategy :: strategy(), + strategy :: strategy() | 'undefined', children = [] :: [child_rec()], - dynamics :: ?DICT(pid(), list()) | ?SET(pid()), - intensity :: non_neg_integer(), - period :: pos_integer(), + dynamics :: ?DICT(pid(), list()) | ?SET(pid()) | 'undefined', + intensity :: non_neg_integer() | 'undefined', + period :: pos_integer() | 'undefined', restarts = [], module, args}). -- cgit v1.2.3 From cc5a470ee25f7db55b586f4908e7e6b9057cafea Mon Sep 17 00:00:00 2001 From: Hans Bolinder Date: Wed, 30 Sep 2015 16:15:26 +0200 Subject: stdlib: Refactor the supervisor module's state The field 'dynamics' in #state{} is a union of two opaque types, which is possibly problematic. Tagging the types should make the code safe for warnings from future versions of Dialyzer. --- lib/stdlib/src/supervisor.erl | 66 +++++++++++++++++++++++-------------------- 1 file changed, 35 insertions(+), 31 deletions(-) (limited to 'lib/stdlib/src') diff --git a/lib/stdlib/src/supervisor.erl b/lib/stdlib/src/supervisor.erl index 142aaa8688..23f3aaee1f 100644 --- a/lib/stdlib/src/supervisor.erl +++ b/lib/stdlib/src/supervisor.erl @@ -109,7 +109,9 @@ -record(state, {name, strategy :: strategy() | 'undefined', children = [] :: [child_rec()], - dynamics :: ?DICT(pid(), list()) | ?SET(pid()) | 'undefined', + dynamics :: {'dict', ?DICT(pid(), list())} + | {'set', ?SET(pid())} + | 'undefined', intensity :: non_neg_integer() | 'undefined', period :: pos_integer() | 'undefined', restarts = [], @@ -577,7 +579,7 @@ handle_cast({try_again_restart,Pid}, #state{children=[Child]}=State) when ?is_simple(State) -> RT = Child#child.restart_type, RPid = restarting(Pid), - case dynamic_child_args(RPid, dynamics_db(RT, State#state.dynamics)) of + case dynamic_child_args(RPid, RT, State#state.dynamics) of {ok, Args} -> {M, F, _} = Child#child.mfargs, NChild = Child#child{pid = RPid, mfargs = {M, F, Args}}, @@ -735,7 +737,7 @@ handle_start_child(Child, State) -> restart_child(Pid, Reason, #state{children = [Child]} = State) when ?is_simple(State) -> RestartType = Child#child.restart_type, - case dynamic_child_args(Pid, dynamics_db(RestartType, State#state.dynamics)) of + case dynamic_child_args(Pid, RestartType, State#state.dynamics) of {ok, Args} -> {M, F, _} = Child#child.mfargs, NChild = Child#child{pid = Pid, mfargs = {M, F, Args}}, @@ -812,14 +814,16 @@ restart(simple_one_for_one, Child, State) -> State#state.dynamics)), case do_start_child_i(M, F, A) of {ok, Pid} -> - NState = State#state{dynamics = ?DICTS:store(Pid, A, Dynamics)}, + DynamicsDb = {dict, ?DICTS:store(Pid, A, Dynamics)}, + NState = State#state{dynamics = DynamicsDb}, {ok, NState}; {ok, Pid, _Extra} -> - NState = State#state{dynamics = ?DICTS:store(Pid, A, Dynamics)}, + DynamicsDb = {dict, ?DICTS:store(Pid, A, Dynamics)}, + NState = State#state{dynamics = DynamicsDb}, {ok, NState}; {error, Error} -> - NState = State#state{dynamics = ?DICTS:store(restarting(OldPid), A, - Dynamics)}, + DynamicsDb = {dict, ?DICTS:store(restarting(OldPid), A, Dynamics)}, + NState = State#state{dynamics = DynamicsDb}, report_error(start_error, Error, Child, State#state.name), {try_again, NState} end; @@ -1102,31 +1106,32 @@ save_child(Child, #state{children = Children} = State) -> State#state{children = [Child |Children]}. save_dynamic_child(temporary, Pid, _, #state{dynamics = Dynamics} = State) -> - State#state{dynamics = ?SETS:add_element(Pid, dynamics_db(temporary, Dynamics))}; + DynamicsDb = dynamics_db(temporary, Dynamics), + State#state{dynamics = {set, ?SETS:add_element(Pid, DynamicsDb)}}; save_dynamic_child(RestartType, Pid, Args, #state{dynamics = Dynamics} = State) -> - State#state{dynamics = ?DICTS:store(Pid, Args, dynamics_db(RestartType, Dynamics))}. + DynamicsDb = dynamics_db(RestartType, Dynamics), + State#state{dynamics = {dict, ?DICTS:store(Pid, Args, DynamicsDb)}}. dynamics_db(temporary, undefined) -> ?SETS:new(); dynamics_db(_, undefined) -> ?DICTS:new(); -dynamics_db(_,Dynamics) -> - Dynamics. - -dynamic_child_args(Pid, Dynamics) -> - case ?SETS:is_set(Dynamics) of - true -> - {ok, undefined}; - false -> - ?DICTS:find(Pid, Dynamics) - end. +dynamics_db(_, {_Tag, DynamicsDb}) -> + DynamicsDb. + +dynamic_child_args(_Pid, temporary, _DynamicsDb) -> + {ok, undefined}; +dynamic_child_args(Pid, _RT, {dict, DynamicsDb}) -> + ?DICTS:find(Pid, DynamicsDb); +dynamic_child_args(_Pid, _RT, undefined) -> + error. state_del_child(#child{pid = Pid, restart_type = temporary}, State) when ?is_simple(State) -> NDynamics = ?SETS:del_element(Pid, dynamics_db(temporary, State#state.dynamics)), - State#state{dynamics = NDynamics}; + State#state{dynamics = {set, NDynamics}}; state_del_child(#child{pid = Pid, restart_type = RType}, State) when ?is_simple(State) -> NDynamics = ?DICTS:erase(Pid, dynamics_db(RType, State#state.dynamics)), - State#state{dynamics = NDynamics}; + State#state{dynamics = {dict, NDynamics}}; state_del_child(Child, State) -> NChildren = del_child(Child#child.name, State#state.children), State#state{children = NChildren}. @@ -1160,19 +1165,19 @@ split_child(_, [], After) -> get_child(Name, State) -> get_child(Name, State, false). + get_child(Pid, State, AllowPid) when AllowPid, is_pid(Pid) -> get_dynamic_child(Pid, State); get_child(Name, State, _) -> lists:keysearch(Name, #child.name, State#state.children). get_dynamic_child(Pid, #state{children=[Child], dynamics=Dynamics}) -> - DynamicsDb = dynamics_db(Child#child.restart_type, Dynamics), - case is_dynamic_pid(Pid, DynamicsDb) of + case is_dynamic_pid(Pid, Dynamics) of true -> {value, Child#child{pid=Pid}}; false -> RPid = restarting(Pid), - case is_dynamic_pid(RPid, DynamicsDb) of + case is_dynamic_pid(RPid, Dynamics) of true -> {value, Child#child{pid=RPid}}; false -> @@ -1183,13 +1188,12 @@ get_dynamic_child(Pid, #state{children=[Child], dynamics=Dynamics}) -> end end. -is_dynamic_pid(Pid, Dynamics) -> - case ?SETS:is_set(Dynamics) of - true -> - ?SETS:is_element(Pid, Dynamics); - false -> - ?DICTS:is_key(Pid, Dynamics) - end. +is_dynamic_pid(Pid, {dict, Dynamics}) -> + ?DICTS:is_key(Pid, Dynamics); +is_dynamic_pid(Pid, {set, Dynamics}) -> + ?SETS:is_element(Pid, Dynamics); +is_dynamic_pid(_Pid, undefined) -> + false. replace_child(Child, State) -> Chs = do_replace_child(Child, State#state.children), -- cgit v1.2.3