Re: [PATCH 3/3] cleanup: Drop pointless label at end of function

["Daniel P. Berrangé" <berrange@redhat.com>]

On Wed, Mar 19, 2025 at 02:42:21PM -0500, Corey Minyard wrote:
> On Wed, Mar 19, 2025 at 08:21:20PM +0100, Markus Armbruster wrote:
> > Corey Minyard <corey@minyard.net> writes:
> > 
> > > Is this official coding style?  I'm not a big fan of having return
> > > statements in the middle of functions, I generally only put them at
> > > the beginning or the end.
> > 
> > There's nothing in docs/devel/style.rst.
> > 
> > I count more than 42,000 return statements with indentation > 4.  These
> > are either within some block, or incorrectly indented.  I'd bet my own
> > money that it's the former for pretty much all of them.
> > 
> > I count less than 130 labels right before a return statement at end of a
> > function.
> > 
> > Based on that, I'd say return in the middle of function is
> > overwhelmingly common in our code.
> > 
> 
> Ok.  It's not a huge deal to me.  I think it's more dangerous to
> have returns in the middle; they are easy to miss and an "out:" at the
> end make it more clear there are returns in the middle.  But that's
> just my opinion.  To make wholesale changes like this I would prefer
> it be in the style guide.  But, I don't want to start a holy war,
> either.  Sigh.

In traditional C, I would agree with you that mid-function 'return's
are often a bad idea, because they complicate free'ing of memory and
tend to actively encourage memory/resource leaks.

With our adoption of g_auto/g_autofree, that problem has been
eliminated across a decently large subset of code. This swings
the balance so that having mid-function 'return's often (but not
always) results in shorter & easier to understand code, with few
leak possiblities, provided g_auto/autofree is sufficient to deal
with all cleanup needs.

There will still be cases where it makes more sense to use 'goto'
for cleanup, since g_auto/autofree is sufficient in all scenarios.

Thus I don't think we should have a rule that strictly dictates
either way. Better to leave it upto author's judgement call as to
which approach results in clearer code for each particular function.
I would still encourage maximising use of 'g_auto/autofree' where
practical.

With regards,
Daniel
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