> On Mar 7, 2026, at 03:33, Masahiko Sawada <[email protected]> wrote:
>
> Hi,
>
> On Tue, Mar 3, 2026 at 5:31 PM Chao Li <[email protected]> wrote:
>>
>>
>>
>>> On Dec 25, 2025, at 11:34, Chao Li <[email protected]> wrote:
>>>
>>>
>>>
>>>> On Dec 25, 2025, at 11:12, Chao Li <[email protected]> wrote:
>>>>
>>>> Hi Hackers,
>>>>
>>>> I noticed this error while working on [1].
>>>>
>>>> In BufFile, the fields is claimed as an array:
>>>> ```
>>>> struct BufFile
>>>> {
>>>> File *files; /* palloc'd array with numFiles entries */
>>>> ```
>>>>
>>>> However, it’s allocated by palloc_object():
>>>> ```
>>>> file->files = palloc_object(File);
>>>> ```
>>>>
>>>> And reallocated by repalloc():
>>>> ```
>>>> file->files = (File *) repalloc(file->files,
>>>> (file->numFiles + 1) * sizeof(File));
>>>> ```
>>>>
>>>> This trivial patch just changes to use palloc_array/repalloc_array, which
>>>> makes the intent clearer.
>>>>
>>>> Best regards,
>>>> --
>>>> Chao Li (Evan)
>>>> HighGo Software Co., Ltd.
>>>> https://www.highgo.com/
>>>>
>>>>
>>>>
>>>>
>>>> <v1-0001-Use-palloc_array-repalloc_array-for-BufFile-file-.patch>
>>>
>>>
>>> Sorry for missing the reference of [1]:
>>>
>>> [1] https://postgr.es/m/[email protected]
>>>
>>> Best regards,
>>> --
>>> Chao Li (Evan)
>>> HighGo Software Co., Ltd.
>>> https://www.highgo.com/
>>>
>>
>> PFA v2:
>> * Rebased
>> * Updated the commit message
>
> I've reviewed the v2 patch and here is a comment:
>
> - file->files = palloc_object(File);
> + file->files = palloc_array(File, 1);
>
> I'm not a fan of this change. This change looks like trying to
> distinguish allocated memory by palloc_object() and palloc_array()
> even though underlying memory is identical. I'm concerned about this
> change creating unnecessary coding conventions.
>
Hi Masahiho-san,
Thank you so much for taking the time to review this patch.
Actually, this change was my original motivation for creating the patch. When I
first read the code, I was confused why the field was named with the plural
“files" even though it was allocated with palloc_object(). After reading
further, I saw that the memory is later enlarged with repalloc, so it became
clear that file->files is really meant to be an array.
To me, the allocation method should reflect the actual meaning of the object.
Here, file->files is an array, no matter how many elements it currently
contains. Even if it only has one element at the moment, semantically it is
still an array.
By “creating unnecessary coding conventions”, are you concerned that this
change might encourage people to always use palloc_array(type, 1) when
allocating a single object? That concern is understandable, but I think it
should depend on the real semantics. If the memory is for a single object, then
of course palloc_array() should be wrong.
Given the nature of C, a "File *" can point either to a single File object or
to a File array. In that sense, palloc_array() makes it explicit that this
pointer is intended to represent an array, while palloc_object() suggests a
single object. So I think changing this to palloc_array() improves readability
in this case.
Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/
