Sign Up
Log In
Log In
or
Sign Up
Places
All Projects
Status Monitor
Collapse sidebar
home:Ledest:erlang
erlang
3941-erl_lint-Warn-on-matching-float-0.0.patch
Overview
Repositories
Revisions
Requests
Users
Attributes
Meta
File 3941-erl_lint-Warn-on-matching-float-0.0.patch of Package erlang
From 5e193bd4ff0b4b511ecc89f35fcf14aa5989a21c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?John=20H=C3=B6gberg?= <john@erlang.org> Date: Tue, 1 Aug 2023 12:59:18 +0200 Subject: [PATCH] erl_lint: Warn on matching float 0.0 --- lib/stdlib/src/erl_lint.erl | 33 +++++++++++++++++++++++++++- lib/stdlib/test/erl_lint_SUITE.erl | 35 ++++++++++++++++++++++++++++-- 2 files changed, 65 insertions(+), 3 deletions(-) diff --git a/lib/stdlib/src/erl_lint.erl b/lib/stdlib/src/erl_lint.erl index 55e53cad3d..893fe4dbae 100644 --- a/lib/stdlib/src/erl_lint.erl +++ b/lib/stdlib/src/erl_lint.erl @@ -320,6 +320,9 @@ format_error({illegal_guard_local_call, {F,A}}) -> io_lib:format("call to local/imported function ~tw/~w is illegal in guard", [F,A]); format_error(illegal_guard_expr) -> "illegal guard expression"; +format_error(match_float_zero) -> + "matching on the float 0.0 will no longer also match -0.0 in OTP 27. If " + "you specifically intend to match 0.0 alone, write +0.0 instead."; %% --- maps --- format_error(illegal_map_construction) -> "only association operators '=>' are allowed in map construction"; @@ -672,6 +675,9 @@ start(File, Opts) -> true, Opts)}, {singleton_typevar, bool_option(warn_singleton_typevar, nowarn_singleton_typevar, + true, Opts)}, + {match_float_zero, + bool_option(warn_match_float_zero, nowarn_match_float_zero, true, Opts)} ], Enabled1 = [Category || {Category,true} <- Enabled0], @@ -1704,7 +1710,12 @@ pattern({var,Anno,V}, _Vt, Old, St) -> pat_var(V, Anno, Old, [], St); pattern({char,_Anno,_C}, _Vt, _Old, St) -> {[],[],St}; pattern({integer,_Anno,_I}, _Vt, _Old, St) -> {[],[],St}; -pattern({float,_Anno,_F}, _Vt, _Old, St) -> {[],[],St}; +pattern({float,Anno,F}, _Vt, _Old, St0) -> + St = case F == 0 andalso is_warn_enabled(match_float_zero, St0) of + true -> add_warning(Anno, match_float_zero, St0); + false -> St0 + end, + {[], [], St}; pattern({atom,Anno,A}, _Vt, _Old, St) -> {[],[],keyword_warning(Anno, A, St)}; pattern({string,_Anno,_S}, _Vt, _Old, St) -> {[],[],St}; @@ -2149,6 +2160,9 @@ gexpr({op,_,'andalso',L,R}, Vt, St) -> gexpr_list([L,R], Vt, St); gexpr({op,_,'orelse',L,R}, Vt, St) -> gexpr_list([L,R], Vt, St); +gexpr({op,_Anno,EqOp,L,R}, Vt, St0) when EqOp =:= '=:='; EqOp =:= '=/=' -> + St1 = expr_check_match_zero(R, expr_check_match_zero(L, St0)), + gexpr_list([L,R], Vt, St1); gexpr({op,Anno,Op,L,R}, Vt, St0) -> {Avt,St1} = gexpr_list([L,R], Vt, St0), case is_gexpr_op(Op, 2) of @@ -2565,6 +2579,9 @@ expr({op,Anno,Op,L,R}, Vt, St0) when Op =:= 'orelse'; Op =:= 'andalso' -> {Evt2,St2} = expr(R, Vt1, St1), Evt3 = vtupdate(vtunsafe({Op,Anno}, Evt2, Vt1), Evt2), {vtmerge(Evt1, Evt3),St2}; +expr({op,_Anno,EqOp,L,R}, Vt, St0) when EqOp =:= '=:='; EqOp =:= '=/=' -> + St = expr_check_match_zero(R, expr_check_match_zero(L, St0)), + expr_list([L,R], Vt, St); %They see the same variables expr({op,_Anno,_Op,L,R}, Vt, St) -> expr_list([L,R], Vt, St); %They see the same variables %% The following are not allowed to occur anywhere! @@ -2573,6 +2590,20 @@ expr({remote,_Anno,M,_F}, _Vt, St) -> expr({ssa_check_when,_Anno,_WantedResult,_Args,_Tag,_Exprs}, _Vt, St) -> {[], St}. +%% Checks whether 0.0 occurs naked in the LHS or RHS of an equality check. Note +%% that we do not warn when it's being used as arguments for expressions in +%% in general: `A =:= abs(0.0)` is fine. +expr_check_match_zero({float,Anno,F}, St) -> + case F == 0 andalso is_warn_enabled(match_float_zero, St) of + true -> add_warning(Anno, match_float_zero, St); + false -> St + end; +expr_check_match_zero({cons,_Anno,H,T}, St) -> + expr_check_match_zero(H, expr_check_match_zero(T, St)); +expr_check_match_zero({tuple,_Anno,Es}, St) -> + foldl(fun expr_check_match_zero/2, St, Es); +expr_check_match_zero(_Expr, St) -> + St. %% expr_list(Expressions, Variables, State) -> %% {UsedVarTable,State} diff --git a/lib/stdlib/test/erl_lint_SUITE.erl b/lib/stdlib/test/erl_lint_SUITE.erl index 81bc3e9a0d..3c45dd1cb9 100644 --- a/lib/stdlib/test/erl_lint_SUITE.erl +++ b/lib/stdlib/test/erl_lint_SUITE.erl @@ -80,7 +80,8 @@ unused_record/1, unused_type2/1, eep49/1, - redefined_builtin_type/1]). + redefined_builtin_type/1, + match_float_zero/1]). suite() -> [{ct_hooks,[ts_install_cth]}, @@ -110,7 +110,8 @@ all() -> underscore_match, unused_record, unused_type2, eep49, redefined_builtin_type, - singleton_type_var_errors]. + singleton_type_var_errors, + match_float_zero]. groups() -> [{unused_vars_warn, [], @@ -5064,6 +5066,35 @@ redefined_builtin_type(Config) -> [] = run(Config, Ts), ok. +match_float_zero(Config) -> + Ts = [{float_zero_1, + <<"t(+0.0) -> ok.\n" + "k(-0.0) -> ok.\n">>, + [], + []}, + {float_zero_2, + <<"t(0.0) -> ok.\n" + "k({0.0}) -> ok.\n">>, + [], + {warnings,[{{1,23},erl_lint,match_float_zero}, + {{2,4},erl_lint,match_float_zero}]}}, + {float_zero_3, + <<"t(A) when A =:= 0.0 -> ok;\n" %% Should warn. + "t(A) when A =:= {0.0} -> ok.\n" %% Should warn. + "k(A) -> A =:= 0.0.\n" %% Should warn. + "q(A) -> A =:= {0.0}.\n" %% Should warn. + "z(A) when A =:= +0.0 -> ok;\n" %% Should not warn. + "z(A) when A =:= {+0.0} -> ok.\n">>, %% Should not warn. + [], + {warnings,[{{1,37},erl_lint,match_float_zero}, + {{2,18},erl_lint,match_float_zero}, + {{3,15},erl_lint,match_float_zero}, + {{4,16},erl_lint,match_float_zero}]}} + ], + [] = run(Config, Ts), + + ok. + format_error(E) -> lists:flatten(erl_lint:format_error(E)). -- 2.35.3
Locations
Projects
Search
Status Monitor
Help
OpenBuildService.org
Documentation
API Documentation
Code of Conduct
Contact
Support
@OBShq
Terms
openSUSE Build Service is sponsored by
The Open Build Service is an
openSUSE project
.
Sign Up
Log In
Places
Places
All Projects
Status Monitor
