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merged 4 commits into from
Dec 22, 2024
Merged

Deprecate complex module expressions in &mod.fun/arity captures #14095

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5f5ef9c
Refactor: distinguish between sequential & arity
sabiwara Dec 21, 2024
d4c626c
Deprecate complex module expressions in &mod.fun/arity captures
sabiwara Dec 21, 2024
8617fe6
Apply feedback from review
sabiwara Dec 21, 2024
34484a9
Remove test for deprecated syntax
sabiwara Dec 21, 2024
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70 changes: 45 additions & 25 deletions lib/elixir/src/elixir_fn.erl
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Original file line number Diff line number Diff line change
Expand Up @@ -41,17 +41,17 @@ fn_arity(Args) -> length(Args).
capture(Meta, {'/', _, [{{'.', _, [M, F]} = Dot, RequireMeta, []}, A]}, S, E) when is_atom(F), is_integer(A) ->
Args = args_from_arity(Meta, A, E),
handle_capture_possible_warning(Meta, RequireMeta, M, F, A, E),
capture_require({Dot, RequireMeta, Args}, S, E, true);
capture_require({Dot, RequireMeta, Args}, S, E, arity);

capture(Meta, {'/', _, [{F, ImportMeta, C}, A]}, S, E) when is_atom(F), is_integer(A), is_atom(C) ->
Args = args_from_arity(Meta, A, E),
capture_import({F, ImportMeta, Args}, S, E, true);
capture_import({F, ImportMeta, Args}, S, E, arity);

capture(_Meta, {{'.', _, [_, Fun]}, _, Args} = Expr, S, E) when is_atom(Fun), is_list(Args) ->
capture_require(Expr, S, E, is_sequential_and_not_empty(Args));
capture_require(Expr, S, E, check_sequential_and_not_empty(Args));

capture(Meta, {{'.', _, [_]}, _, Args} = Expr, S, E) when is_list(Args) ->
capture_expr(Meta, Expr, S, E, false);
capture_expr(Meta, Expr, S, E, non_sequential);

capture(Meta, {'__block__', _, [Expr]}, S, E) ->
capture(Meta, Expr, S, E);
Expand All @@ -60,31 +60,43 @@ capture(Meta, {'__block__', _, _} = Expr, _S, E) ->
file_error(Meta, E, ?MODULE, {block_expr_in_capture, Expr});

capture(_Meta, {Atom, _, Args} = Expr, S, E) when is_atom(Atom), is_list(Args) ->
capture_import(Expr, S, E, is_sequential_and_not_empty(Args));
capture_import(Expr, S, E, check_sequential_and_not_empty(Args));

capture(Meta, {Left, Right}, S, E) ->
capture(Meta, {'{}', Meta, [Left, Right]}, S, E);

capture(Meta, List, S, E) when is_list(List) ->
capture_expr(Meta, List, S, E, is_sequential_and_not_empty(List));
capture_expr(Meta, List, S, E, check_sequential_and_not_empty(List));

capture(Meta, Integer, _S, E) when is_integer(Integer) ->
file_error(Meta, E, ?MODULE, {capture_arg_outside_of_capture, Integer});

capture(Meta, Arg, _S, E) ->
invalid_capture(Meta, Arg, E).

capture_import({Atom, ImportMeta, Args} = Expr, S, E, Sequential) ->
Res = Sequential andalso
capture_import({Atom, ImportMeta, Args} = Expr, S, E, ArgsType) ->
Res = ArgsType /= non_sequential andalso
elixir_dispatch:import_function(ImportMeta, Atom, length(Args), E),
handle_capture(Res, ImportMeta, ImportMeta, Expr, S, E, Sequential).
handle_capture(Res, ImportMeta, ImportMeta, Expr, S, E, ArgsType).

capture_require({{'.', DotMeta, [Left, Right]}, RequireMeta, Args}, S, E, Sequential) ->
capture_require({{'.', DotMeta, [Left, Right]}, RequireMeta, Args}, S, E, ArgsType) ->
case escape(Left, E, []) of
{EscLeft, []} ->
{ELeft, SE, EE} = elixir_expand:expand(EscLeft, S, E),

Res = Sequential andalso case ELeft of
case ELeft of
_ when ArgsType /= arity ->
ok;
Atom when is_atom(Atom) ->
ok;
{Var, _, Ctx} when is_atom(Var), is_atom(Ctx) ->
ok;
_ ->
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@josevalim josevalim Dec 21, 2024

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Add a TODO to convert to error on v2.0 :)

elixir_errors:file_warn(RequireMeta, E, ?MODULE,
{complex_module_capture, Left, Right, length(Args)})
end,

Res = ArgsType /= non_sequential andalso case ELeft of
{Name, _, Context} when is_atom(Name), is_atom(Context) ->
{remote, ELeft, Right, length(Args)};
_ when is_atom(ELeft) ->
Expand All @@ -94,24 +106,25 @@ capture_require({{'.', DotMeta, [Left, Right]}, RequireMeta, Args}, S, E, Sequen
end,

Dot = {{'.', DotMeta, [ELeft, Right]}, RequireMeta, Args},
handle_capture(Res, RequireMeta, DotMeta, Dot, SE, EE, Sequential);
handle_capture(Res, RequireMeta, DotMeta, Dot, SE, EE, ArgsType);

{EscLeft, Escaped} ->
Dot = {{'.', DotMeta, [EscLeft, Right]}, RequireMeta, Args},
capture_expr(RequireMeta, Dot, S, E, Escaped, Sequential)
capture_expr(RequireMeta, Dot, S, E, Escaped, ArgsType)
end.

handle_capture(false, Meta, _DotMeta, Expr, S, E, Sequential) ->
capture_expr(Meta, Expr, S, E, Sequential);
handle_capture(LocalOrRemote, Meta, DotMeta, _Expr, S, E, _Sequential) ->
handle_capture(false, Meta, _DotMeta, Expr, S, E, ArgsType) ->
capture_expr(Meta, Expr, S, E, ArgsType);
handle_capture(LocalOrRemote, Meta, DotMeta, _Expr, S, E, _ArgsType) ->
{LocalOrRemote, Meta, DotMeta, S, E}.

capture_expr(Meta, Expr, S, E, Sequential) ->
capture_expr(Meta, Expr, S, E, [], Sequential).
capture_expr(Meta, Expr, S, E, Escaped, Sequential) ->
capture_expr(Meta, Expr, S, E, ArgsType) ->
capture_expr(Meta, Expr, S, E, [], ArgsType).
capture_expr(Meta, Expr, S, E, Escaped, ArgsType) ->
case escape(Expr, E, Escaped) of
{_, []} when not Sequential ->
{_, []} when ArgsType == non_sequential ->
invalid_capture(Meta, Expr, E);
% TODO remove this clause once we raise on complex module captures like &get_mod().fun/0
{{{'.', _, [_, _]} = Dot, _, Args}, []} ->
Meta2 = lists:keydelete(no_parens, 1, Meta),
Fn = {fn, Meta2, [{'->', Meta2, [[], {Dot, Meta2, Args}]}]},
Expand Down Expand Up @@ -166,12 +179,12 @@ args_from_arity(_Meta, A, _E) when is_integer(A), A >= 0, A =< 255 ->
args_from_arity(Meta, A, E) ->
file_error(Meta, E, ?MODULE, {invalid_arity_for_capture, A}).

is_sequential_and_not_empty([]) -> false;
is_sequential_and_not_empty(List) -> is_sequential(List, 1).
check_sequential_and_not_empty([]) -> non_sequential;
check_sequential_and_not_empty(List) -> check_sequential(List, 1).

is_sequential([{'&', _, [Int]} | T], Int) -> is_sequential(T, Int + 1);
is_sequential([], _Int) -> true;
is_sequential(_, _Int) -> false.
check_sequential([{'&', _, [Int]} | T], Int) -> check_sequential(T, Int + 1);
check_sequential([], _Int) -> sequential;
check_sequential(_, _Int) -> non_sequential.

handle_capture_possible_warning(Meta, DotMeta, Mod, Fun, Arity, E) ->
case (Arity =:= 0) andalso (lists:keyfind(no_parens, 1, DotMeta) /= {no_parens, true}) of
Expand All @@ -186,6 +199,13 @@ format_error({parens_remote_capture, Mod, Fun}) ->
io_lib:format("extra parentheses on a remote function capture &~ts.~ts()/0 have been "
"deprecated. Please remove the parentheses: &~ts.~ts/0",
['Elixir.Macro':to_string(Mod), Fun, 'Elixir.Macro':to_string(Mod), Fun]);
format_error({complex_module_capture, Mod, Fun, Arity}) ->
io_lib:format("using complex expressions for modules in &module.function/arity capture syntax has been deprecated:\n"
" &~ts.~ts/~B\n\n"
"You can either:\n"
" * use the fn syntax\n"
" * assign the module to a variable if it can be evaluated outside of the capture",
['Elixir.Macro':to_string(Mod), Fun, Arity]);
format_error(clauses_with_different_arities) ->
"cannot mix clauses with different arities in anonymous functions";
format_error(defaults_in_args) ->
Expand Down
23 changes: 23 additions & 0 deletions lib/elixir/test/elixir/kernel/warning_test.exs
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Original file line number Diff line number Diff line change
Expand Up @@ -2194,6 +2194,29 @@ defmodule Kernel.WarningTest do
)
end

test "deprecate &module.fun/arity captures with complex expressions as modules" do
assert_warn_eval(
[
"nofile:2:",
"""
using complex expressions for modules in &module.function/arity capture syntax has been deprecated:
&hd(modules).module_info/0

You can either:
* use the fn syntax
* assign the module to a variable if it can be evaluated outside of the capture
"""
],
"""
defmodule Sample do
def foo(modules), do: &hd(modules).module_info/0
end
"""
)
after
purge(Sample)
end

defp assert_compile_error(messages, string) do
captured =
capture_err(fn ->
Expand Down
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