Issue erlang#8099: Accept empty list of binaries in binary:join/2 whi…

…ch returns an empty binary
onno-vos-dev · Feb 8, 2024 · 335d9fc · 335d9fc
1 parent 7319cdf
commit 335d9fc
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diff --git a/lib/stdlib/src/binary.erl b/lib/stdlib/src/binary.erl
@@ -948,6 +948,7 @@ _Example:_
 """.
 -doc(#{since => <<"OTP 27.0">>}).
 -spec join([binary()], binary()) -> binary().
+join([], _Separator) -> <<>>;
 join([H], _Separator) -> H;
 join([H | T], Separator) ->
     join(T, Separator, H).

diff --git a/lib/stdlib/test/binary_module_SUITE.erl b/lib/stdlib/test/binary_module_SUITE.erl
@@ -262,7 +262,11 @@ badargs(Config) when is_list(Config) ->
     badarg = ?MASK_ERROR(binary:encode_hex(foo)),
 
     badarg = ?MASK_ERROR(binary:join([<<"a">>], ", ")),
-    badarg = ?MASK_ERROR(binary:join([], <<",">>)),
+    badarg = ?MASK_ERROR(binary:join([""], <<",">>)),
+    badarg = ?MASK_ERROR(binary:join([123], <<",">>)),
+    badarg = ?MASK_ERROR(binary:join(123, <<",">>)),
+    badarg = ?MASK_ERROR(binary:join(#{}, <<",">>)),
+    badarg = ?MASK_ERROR(binary:join(foo, <<",">>)),
     ok.
 
 %% Whitebox test to force special trap conditions in
@@ -1588,6 +1592,7 @@ do_hex_roundtrip(Bytes) ->
 join(Config) when is_list(Config) ->
     <<"a, b, c">> = binary:join([<<"a">>, <<"b">>, <<"c">>], <<", ">>),
     <<"a">> = binary:join([<<"a">>], <<", ">>),
+    <<>> = binary:join([], <<", ">>),
     badarg = ?MASK_ERROR(binary:join([<<"a">>], ", ")),
     badarg = ?MASK_ERROR(binary:join([], <<",">>)).