Re: [PATCH v2 01/10] t: add helper to convert object IDs to paths

> On Tue, Jun 18, 2019 at 06:15:46PM +0200, Johannes Schindelin wrote:
> > > Regardless of how it is implemented, I have another gripe with this
> > > helper: the way it must be used requires a process: $(test_out_to_path
> > > $foo)
> >
> > Indeed.
> >
> > > And looking through this patch series, I see a gazillion of *new*
> > > process substitutions $(test_something...) and $(basename $whatever).
> > > Can't we do something about it?
> >
> > I wish there was. Unix shell scripting has not evolved much in the past,
> > what, 3 decades? So I don't really see a way to "pass variables by
> > reference" to shell functions, short of calling `eval` (which buys
> > preciously little as it _also_ has to spawn a new process [*1*]).
>
> > Footnote *1*: Theoretically, it could be a *ton* faster by using threads
> > on Windows. But threads are pretty much an afterthought on Unix/Linux, so
> > no mainstream POSIX shell supports this. They all `fork()` to interpret an
> > `eval` as far as I can tell.
>
> 'eval' doesn't fork().  It can't possibly fork(), because if it did,
> then any variables set in the eval-ed code snippet couldn't be visible
> outside the 'eval'.