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Fix recently-introduced Fdelete bug

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Problem reported by Pip Cet in:
https://lists.gnu.org/r/emacs-devel/2020-08/msg00444.html
* src/fns.c (Fdelete): Fix correctness bug via a simpler (though more
memory-intensive) approach.  It’s probably not worth optimizing
the memory usage yere.
* test/src/fns-tests.el (test-vector-delete): Add test for the bug.
This commit is contained in:
Paul Eggert 2020-08-15 12:32:56 -07:00
parent b467bb531e
commit 748afc183c
2 changed files with 5 additions and 25 deletions
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29
src/fns.c
View file

@ -1749,38 +1749,17 @@ changing the value of a sequence `foo'. */)
{
ptrdiff_t n = 0;
ptrdiff_t size = ASIZE (seq);
ptrdiff_t neqbits_words = ((size + BITS_PER_BITS_WORD - 1)
/ BITS_PER_BITS_WORD);
USE_SAFE_ALLOCA;
bits_word *neqbits = SAFE_ALLOCA (neqbits_words * sizeof *neqbits);
bits_word neqword = 0;
Lisp_Object *kept = SAFE_ALLOCA (size * sizeof *kept);
for (ptrdiff_t i = 0; i < size; i++)
{
bool neq = NILP (Fequal (AREF (seq, i), elt));
n += neq;
neqbits[i / BITS_PER_BITS_WORD] = neqword = (neqword << 1) + neq;
kept[n] = AREF (seq, i);
n += NILP (Fequal (AREF (seq, i), elt));
}
if (n != size)
{
struct Lisp_Vector *p = allocate_vector (n);
if (n != 0)
{
ptrdiff_t j = 0;
for (ptrdiff_t i = 0; ; i++)
if (neqbits[i / BITS_PER_BITS_WORD]
& ((bits_word) 1 << (i % BITS_PER_BITS_WORD)))
{
p->contents[j++] = AREF (seq, i);
if (j == n)
break;
}
}
XSETVECTOR (seq, p);
}
seq = Fvector (n, kept);
SAFE_FREE ();
}

1
test/src/fns-tests.el
View file

@ -898,5 +898,6 @@
(ert-deftest test-vector-delete ()
(let ((v1 (make-vector 1000 1)))
(should (equal (delete t [nil t]) [nil]))
(should (equal (delete 1 v1) (vector)))
(should (equal (delete 2 v1) v1))))