[tex-live] small bug re installing x86_64-darwin vs. universal-darwin

[Mojca Miklavec]

On Mon, Jan 14, 2013 at 1:59 AM, Adam R. Maxwell wrote:
>
> My point, probably poorly stated, was that if you can reboot into a
> different kernel, as your statement requires, then you must have 64-bit
> hardware.

That's definitely true.

What I meant with "stops working" was that any subsequent operation
(possibly calling tlmgr) that would require calling config.guess again
would detect a different architecture than the one used for installing
TL. And that could lead into problems. (Example: in the early days I
manually switched to x86_64-darwin and then installation failed
because wget.universal-darwin was missing.) In ConTeXt distribution
this was a bigger problem because platform is usually being checked
for during each initialization, not just during installation.

But bottom line: there is an easy solution to that. By using the code
I posted earlier (overwriting the results of config.guess in the perl
code), the Mac platform could be detected properly. It's only a
question of TL developers & Dick deciding that using x86_64 binaries
by default is acceptable and should be done also for command-line
installations, not just for MacTeX.

> Consequently, I don't see any way that TeX Live can "stop
> working" due to such a reboot.  I'm probably missing something…

When manually setting binary PATH, binaries should continue to work.
But tlmgr calling config.guess again might have problems.

> Does TL use config.guess during install?

Yes.

> That seems wrong on the Mac
> unless you're actually compiling, since it makes its guess based on a
> C compiler which likely isn't even available.

Yes, config.guess it flawed on Mac in my opinion, but there is
probably no good alternative that would be general enough to work on a
wide variety of platforms, not just macs.

In case that a compiler isn't available, config.guess would simply
return i386 both on i386 and x86_64 (if nothing else the binaries
would at least still work). I tried to file a bug report to
maintainers, but I didn't manage to explain what I thought was wrong
with the code and I stopped trying.

> Your heuristic looks
> more reasonable for average users.

Nothing stops the TL team to simply overwrite the results of
config.guess with a different heuristic for Mac only. It's just a
matter of decision. The decision to use "universal-darwin" for all
Macs by default was made when x86_64 just came to the market [and one
still had to manually reboot into the 64-bit kernel]. The i386
binaries still work everywhere, but it might be time to reconsider
now?

Mojca