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From: =?utf-8?Q?Dagfinn_Ilmari_Manns=C3=A5ker?= <ilmari@ilmari.org>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Remove useless casts to (char *)
References: <fd1fcedb-3492-4fc8-9e3e-74b97f2db6c7@eisentraut.org>
	<87seor2t03.fsf@wibble.ilmari.org>
	<c2df6122-6090-42f8-85a5-c5475fc6f016@eisentraut.org>
Date: Mon, 10 Feb 2025 17:44:02 +0000
In-Reply-To: <c2df6122-6090-42f8-85a5-c5475fc6f016@eisentraut.org> (Peter
	Eisentraut's message of "Sun, 9 Feb 2025 13:26:13 +0100")
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Peter Eisentraut <peter@eisentraut.org> writes:

> On 06.02.25 12:49, Dagfinn Ilmari Mannsåker wrote:
>> I have only skimmed the patches, but one hunk jumped out at me:
>> Peter Eisentraut <peter@eisentraut.org> writes:
>> 
>>> diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
>>> index 1bf27d93cfa..937a2b02a4f 100644
>>> --- a/src/backend/libpq/pqcomm.c
>>> +++ b/src/backend/libpq/pqcomm.c
>>> @@ -1368,7 +1368,7 @@ internal_flush_buffer(const char *buf, size_t *start, size_t *end)
>>>   	{
>>>   		int			r;
>>>   -		r = secure_write(MyProcPort, (char *) bufptr, bufend -
>>> bufptr);
>>> +		r = secure_write(MyProcPort, unconstify(char *, bufptr), bufend - bufptr);
>>>     		if (r <= 0)
>>>   		{
>> Insted of unconstify here, could we not make secure_write() (and
>> be_tls_write()) take the buffer pointer as const void *, like the
>> attached?
>
> Yeah, that makes sense.  I've committed that.

Thanks, and thanks for catching be_gssapi_write(), which I had missed
due to not having gssapi enabled in my test build.

>  Here is a new patch set rebased over that.

I had a more thorough read-through this time (as well as applying and
building it), and it does make the code a lot more readable.

I noticed you in some places added extra parens around remaining casts
with offset additions, e.g.

-		XLogRegisterData((char *) old_key_tuple->t_data + SizeofHeapTupleHeader,
+		XLogRegisterData(((char *) old_key_tuple->t_data) + SizeofHeapTupleHeader,
 						 old_key_tuple->t_len - SizeofHeapTupleHeader);

But not in others:

-		memcpy((char *) tuple->t_data + SizeofHeapTupleHeader,
-			   (char *) data,
-			   datalen);
+		memcpy((char *) tuple->t_data + SizeofHeapTupleHeader, data, datalen);


I don't have a particularly strong opinion either way (maybe -0.2 on the
extra parens), but I mainly think we should keep it consistent, and not
change it gratuitously.

Greppig indicates to me that the paren-less version is more common:

$ git grep -P '\(\w+\s*\**\) [\w>-]+ \+ \w+' | wc -l
283
$ git grep -P '\(\(\w+\s*\**\) [\w>-]+\) \+ \w+' | wc -l
96

So I think we should leave them as they are.

- ilmari