Re: cleaning perl code

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com>
Cc: Noah Misch <noah(at)leadboat(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: cleaning perl code
Date: 2020-04-11 16:48:50
Message-ID: 19843.1586623730@sss.pgh.pa.us
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Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com> writes:
> On 4/11/20 12:30 AM, Noah Misch wrote:
>> In summary, among those warnings, I see non-negative value in "Code before
>> warnings are enabled" only. While we're changing this, I propose removing
>> Subroutines::RequireFinalReturn. Implicit return values were not a material
>> source of PostgreSQL bugs, yet we've allowed this to litter our code:

> That doesn't mean it won't be a source of problems in future, I've
> actually been bitten by this in the past.

Yeah, as I recall, the reason for the restriction is that if you fall out
without a "return", what's returned is the side-effect value of the last
statement, which might be fairly surprising. Adding explicit "return;"
guarantees an undef result. So when this does prevent a bug it could
be a pretty hard-to-diagnose one. The problem is that it's a really
verbose/pedantic requirement for subs that no one ever examines the
result value of.

Is there a way to modify the test so that it only complains when
the final return is missing and there are other return(s) with values?
That would seem like a more narrowly tailored check.

regards, tom lane

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