Message-ID: <bd4b316a-d0cd-4ccf-b9fe-18621c953645@gmail.com>
Date: Tue, 26 May 2026 10:29:58 -0300
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Subject: Re: Avoid leaking system path from pg_available_extensions
To: Chao Li <li.evan.chao@gmail.com>
Cc: Jim Jones <jim.jones@uni-muenster.de>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>,
 Andrew Dunstan <andrew@dunslane.net>
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 <cf40d36e-e45a-41c2-aea1-7834bcb62da9@uni-muenster.de>
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 <83AF10FE-7655-43DF-A302-3CAC796B572F@gmail.com>
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From: Matheus Alcantara <matheusssilv97@gmail.com>
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On 26/05/26 04:14, Chao Li wrote:
> 
> 
>> On May 22, 2026, at 23:40, Matheus Alcantara <matheusssilv97@gmail.com> wrote:
>>
>> On 22/05/26 04:25, Jim Jones wrote:
>>> On 21/05/2026 17:12, Matheus Alcantara wrote:
>>>> I've reproduced the issue and the fix looks correct to me.
>>> same here, +1
>>
>> Thank you for also testing.
>>
>>> I was wondering if creating a constant for it would be, stylistically
>>> speaking, a cleaner solution. For instance:
>>> #define EXTENSION_SYSTEM_MACRO  "$system"
>>> I realize that it's used only inside get_extension_control_directories()
>>> but since it is even mentioned in the docs, I guess it wouldn't be a bad
>>> idea.
>>
>> I'm not against it but I don't think that it's necessary since as you mention, only get_extension_control_directories() use.
>>
> 
> In theory, I’m not against the idea either. In practice, there are many hard-coded strings in the source tree, and I’m not sure where the right place would be to define this macro.
> 
> Since this string is only used in get_extension_control_directories(), and now it is used three times, I defined it at the beginning of the function and undefined it at the end. Let’s see if there are any objections to that.
> 
> Please see the attached v2.
> 

We have such pattern in other parts of the codebase (e.g 
pg_resetwal.c), so it works for me.

Thanks for the patch.

--
Matheus Alcantara
EDB: https://www.enterprisedb.com