Guillaume Lelarge <guillaume@lelarge.info> writes:
> This query:
> SELECT ARRAY[-1,3,1] & ARRAY[1, 2];
> should give {1} as a result.
> But, on HEAD (and according to his tests, on 9.0.6 and 9.1.2), it
> appears to give en empty array.
Definitely a bug, and I'll bet it goes all the way back.
> Digging on this issue, another user (Julien Rouhaud) made an interesting
> comment on this line of code:
> if (i + j == 0 || (i + j > 0 && *(dr - 1) != db[j]))
> (line 159 of contrib/intarray/_int_tool.c, current HEAD)
> Apparently, the code tries to check the current value of the right side
> array with the previous value of the resulting array. Which clearly
> cannot work if there is no previous value in the resulting array.
> So I worked on a patch to fix this, as I think it is a bug (but I may be
> wrong). Patch is attached and fixes the issue AFAICT.
Yeah, this code is bogus, but it's also pretty unreadable. I think
it's better to get rid of the inconsistently-used pointer arithmetic
and the fundamentally wrong/irrelevant test on i+j, along the lines
of the attached.
regards, tom lane
diff --git a/contrib/intarray/_int_tool.c b/contrib/intarray/_int_tool.c
index 79f018d333b1d6810aa7fd2996c158b41b0263fb..132d15316054d842593468f191eca9053846f706 100644
*** a/contrib/intarray/_int_tool.c
--- b/contrib/intarray/_int_tool.c
*************** inner_int_inter(ArrayType *a, ArrayType
*** 140,146 ****
*db,
*dr;
int i,
! j;
if (ARRISEMPTY(a) || ARRISEMPTY(b))
return new_intArrayType(0);
--- 140,147 ----
*db,
*dr;
int i,
! j,
! k;
if (ARRISEMPTY(a) || ARRISEMPTY(b))
return new_intArrayType(0);
*************** inner_int_inter(ArrayType *a, ArrayType
*** 152,166 ****
r = new_intArrayType(Min(na, nb));
dr = ARRPTR(r);
! i = j = 0;
while (i < na && j < nb)
{
if (da[i] < db[j])
i++;
else if (da[i] == db[j])
{
! if (i + j == 0 || (i + j > 0 && *(dr - 1) != db[j]))
! *dr++ = db[j];
i++;
j++;
}
--- 153,167 ----
r = new_intArrayType(Min(na, nb));
dr = ARRPTR(r);
! i = j = k = 0;
while (i < na && j < nb)
{
if (da[i] < db[j])
i++;
else if (da[i] == db[j])
{
! if (k == 0 || dr[k - 1] != db[j])
! dr[k++] = db[j];
i++;
j++;
}
*************** inner_int_inter(ArrayType *a, ArrayType
*** 168,180 ****
j++;
}
! if ((dr - ARRPTR(r)) == 0)
{
pfree(r);
return new_intArrayType(0);
}
else
! return resize_intArrayType(r, dr - ARRPTR(r));
}
void
--- 169,181 ----
j++;
}
! if (k == 0)
{
pfree(r);
return new_intArrayType(0);
}
else
! return resize_intArrayType(r, k);
}
void
diff --git a/contrib/intarray/expected/_int.out b/contrib/intarray/expected/_int.out
index 6ed3cc6ced096e2e97665e76ceba7fc139415029..4080b9633fe98a91861684e0d82f1297c21b91af 100644
*** a/contrib/intarray/expected/_int.out
--- b/contrib/intarray/expected/_int.out
*************** SELECT '{123,623,445}'::int[] & '{1623,6
*** 137,142 ****
--- 137,148 ----
{623}
(1 row)
+ SELECT '{-1,3,1}'::int[] & '{1,2}';
+ ?column?
+ ----------
+ {1}
+ (1 row)
+
--test query_int
SELECT '1'::query_int;
query_int
diff --git a/contrib/intarray/sql/_int.sql b/contrib/intarray/sql/_int.sql
index b60e936dc520d8308bd16e50681f061dc86e2dfe..216c5c58d615a7cd1a5fe3714c9a5c91fb255138 100644
*** a/contrib/intarray/sql/_int.sql
--- b/contrib/intarray/sql/_int.sql
*************** SELECT '{123,623,445}'::int[] | 623;
*** 24,29 ****
--- 24,30 ----
SELECT '{123,623,445}'::int[] | 1623;
SELECT '{123,623,445}'::int[] | '{1623,623}';
SELECT '{123,623,445}'::int[] & '{1623,623}';
+ SELECT '{-1,3,1}'::int[] & '{1,2}';
--test query_int
