diff options
Diffstat (limited to 'erts/emulator/beam/erl_map.c')
| -rw-r--r-- | erts/emulator/beam/erl_map.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/erts/emulator/beam/erl_map.c b/erts/emulator/beam/erl_map.c index 62dd85e425..9097a36e62 100644 --- a/erts/emulator/beam/erl_map.c +++ b/erts/emulator/beam/erl_map.c @@ -973,7 +973,13 @@ BIF_RETTYPE maps_keys_1(BIF_ALIST_1) { HIPE_WRAPPER_BIF_DISABLE_GC(maps_merge, 2) BIF_RETTYPE maps_merge_2(BIF_ALIST_2) { - if (is_flatmap(BIF_ARG_1)) { + if (BIF_ARG_1 == BIF_ARG_2) { + /* Merging upon itself always returns itself */ + if (is_map(BIF_ARG_1)) { + return BIF_ARG_1; + } + BIF_P->fvalue = BIF_ARG_1; + } else if (is_flatmap(BIF_ARG_1)) { if (is_flatmap(BIF_ARG_2)) { BIF_RET(flatmap_merge(BIF_P, BIF_ARG_1, BIF_ARG_2)); } else if (is_hashmap(BIF_ARG_2)) { @@ -1008,6 +1014,9 @@ static Eterm flatmap_merge(Process *p, Eterm nodeA, Eterm nodeB) { n1 = flatmap_get_size(mp1); n2 = flatmap_get_size(mp2); + if (n1 == 0) return nodeB; + if (n2 == 0) return nodeA; + need = MAP_HEADER_FLATMAP_SZ + 1 + 2 * (n1 + n2); hp = HAlloc(p, need); @@ -1127,6 +1136,7 @@ static Eterm map_merge_mixed(Process *p, Eterm flat, Eterm tree, int swap_args) mp = (flatmap_t*)flatmap_val(flat); n = flatmap_get_size(mp); + if (n == 0) return tree; ks = flatmap_get_keys(mp); vs = flatmap_get_values(mp); |