Regex.split with trailing \K works incorrectly #14467
Labels
Comments
|
You can directly use :re.split till the fix is ready
…On Sat, May 3, 2025 at 5:41 PM error256 ***@***.***> wrote:
*error256* created an issue (elixir-lang/elixir#14467)
<#14467>
Elixir 1.18.3, Erlang/OTP 27.3.3
IO.inspect Regex.split ~r/b\K/, "ababab"IO.inspect :re.split "ababab", "b\\K"
returns
["ab", "ab", "", "ab", "", ""]
["ab", "ab", "ab", ""]
I think Regex.split should return the same result as :re.split.
Non-trailing \Ks and lookbehinds seem to work correctly, this is the only
case.
—
Reply to this email directly, view it on GitHub
<#14467>, or unsubscribe
<https://github.com/notifications/unsubscribe-auth/AGJSGFKLY7JQHXCFIKTQCYD24UZZLAVCNFSM6AAAAAB4MEOPCWVHI2DSMVQWIX3LMV43ASLTON2WKOZTGAZTONRSGY2TONQ>
.
You are receiving this because you are subscribed to this thread.Message
ID: ***@***.***>
|
|
Here is the relevant Erlang code that deals with this and we are missing, in particular the first branch of the case: do_split(Subj, Offset, [[{MainI,MainL}|Sub]|T], NumSub, Limit, Group) ->
NewOffset = MainI+MainL,
KeptLen = MainI - Offset,
case {KeptLen,empty_sub(Sub),MainL} of
{0,true,0} ->
do_split(Subj,NewOffset,T,NumSub,Limit,Group);
_ ->
<<_:Offset/binary,Keep:KeptLen/binary,_/binary>> = Subj,
ESub = extend_subpatterns(Sub,NumSub),
Tail = do_split(Subj, NewOffset, T, NumSub, Limit - 1,Group),
case Group of
false ->
[Keep | dig_subpatterns(Subj,lists:reverse(ESub),Tail)];
true ->
[[Keep | dig_subpatterns(Subj,lists:reverse(ESub),[])]|
Tail]
end
end.
empty_sub([]) ->
true;
empty_sub([{_,0}|T]) ->
empty_sub(T);
empty_sub(_) ->
false. |
|
@josevalim I came to the same conclusion and tried a fix, but it breaks some tests so it might be a breaking change? iex> :re.split "abc", ""
["a", "b", "c", ""]
# main
iex> Regex.split ~r//, "abc"
["", "a", "b", "c", ""]
# the fix
iex> Regex.split ~r//, "abc"
["a", "b", "c", ""] |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Elixir 1.18.3, Erlang/OTP 27.3.3
returns
I think
Regex.splitshould return the same result as:re.split. Non-trailing\Ks and lookbehinds seem to work correctly, this is the only case.The text was updated successfully, but these errors were encountered: