Casting strings to multidimensional arrays yields strange results. In one
case there are discard values and the other a value magically appears.
Trying both of these with the array[] constructor syntax yields the
expected:
ERROR: multidimensional arrays must have array expressions with matching
dimensions

Tested on both 7.4.3 and 7.5dev.

Kris Jurka

jurka=# SELECT '{{1,2},{2,3},{4}}'::int[][];
int4
---------------
{{1},{2},{4}}

jurka=# SELECT '{{1},{2,3},{4,5}}'::int[][];
int4
---------------------
{{1,0},{2,3},{4,5}}


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Kris Jurka <books (AT) ejurka (DOT) com> writes:
Don't think anyone's really thought about it.

"Pad with 0" is a meaningless concept as soon as you think about
nonnumeric data types. I'm not very sure what's even happening
inside the code --- it's a bit surprising it doesn't crash outright
on pass-by-reference data types ...

I'd agree that the truncation behavior is wrong, but I don't want to
get rid of it by causing the padding behavior to happen more often.

regards, tom lane

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Kris Jurka <books (AT) ejurka (DOT) com> writes:
array_in has fairly bizarre behavior when presented with non-rectangular
input data, such as your examples:

I don't recall the details right now of how it chooses the actual array
dimensions, but it's weird. I've been tempted to rewrite it but have
refrained for fear of breaking existing applications. Also, it's not
entirely clear what the behavior *should* be.

Right now I think the sanest behavior would be to throw an error on
non-rectangular input. Once we have support for null elements in
arrays, however, it would arguably be reasonable to pad with NULLs
where needed, so that the above would be read as

{{1,2},{2,3},{4,NULL}}

{{1,NULL},{2,3},{4,5}}

respectively. If that's the direction we want to head in, it would
probably be best to leave array_in alone until we can do that; users
tend to get unhappy when we change behavior repeatedly.

What's your thoughts?

regards, tom lane

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[ cc'ing pghackers in case anyone wants to object ]

Joe Conway <mail (AT) joeconway (DOT) com> writes:
Okay with me. Anyone on pghackers not happy?

Yeah, we can call it a bug fix.

regards, tom lane

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