Re: [PATCH] Prefer getenv("HOME") to find the UNIX home directory

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Anders Kaseorg <andersk(at)mit(dot)edu>
Cc: Daniel Gustafsson <daniel(at)yesql(dot)se>, Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>, alvherre(at)alvh(dot)no-ip(dot)org, pgsql-hackers(at)lists(dot)postgresql(dot)org
Subject: Re: [PATCH] Prefer getenv("HOME") to find the UNIX home directory
Date: 2022-01-09 18:59:02
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Anders Kaseorg <andersk(at)mit(dot)edu> writes:
> On 10/20/21 04:55, Daniel Gustafsson wrote:
>> Is the proposed change portable across all linux/unix systems we support?
>> Reading aobut indicates that it's likely to be, but neither NetBSD nor FreeBSD
>> have the upthread referenced wording in their manpages.

> Since the proposed change falls back to the old behavior if HOME is
> unset or empty, I assume this is a question about convention and not
> literally about whether it will work on these systems. I don’t find it
> surprising that this convention isn’t explicitly called out in every
> system’s manpage for the wrong function, but it still applies to these
> systems.

Given the POSIX requirements, it's basically impossible to believe
that there are interesting cases where $HOME isn't set. Thus, it
seems to me that keeping the getpwuid calls will just mean carrying
untestable dead code, so we should simplify matters by ripping
those out and *only* consulting $HOME.

The v1 patch also neglects the matter of documentation. I think
the simplest and most transparent thing to do is just to explicitly
mention $HOME everyplace we talk about files that are sought there,
in place of our current convention to write "~". (I'm too lazy
to go digging in the git history, but I have a feeling that this is
undoing somebody's intentional change from a long time back.)

BTW, not directly impacted by this patch but adjacent to it,
I noted that on Windows psql's \cd defaults to changing to "/".
That seems a bit surprising, and we definitely fail to document it.
I settled for noting it in the documentation, but should we make
it do something else?

PFA v2 patch.

regards, tom lane

Attachment Content-Type Size
v2-0001-use-HOME-for-home-directory.patch text/x-diff 13.3 KB

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