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Faré  
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 More options Jun 11 2011, 8:25 pm
From: Faré <fah...@gmail.com>
Date: Sat, 11 Jun 2011 20:25:18 -0400
Local: Sat, Jun 11 2011 8:25 pm
Subject: [Sbcl-devel] Logical pathnames vs ASDF & SBCL
TL;DR: ASDF currently doesn't play so well with logical pathnames.
I'm seeking advice on how to make things better —
or on whether it's worth the trouble.

Dear all,

Pascal's recent plight with logical pathnames on SBCL
once again rises the issue of how much ASDF (or SBCL)
should support logical pathname users, and
how they should behave to make logical pathname users happy.

With case-sensitivity issues, things only get worse!

(Note: personally inviting James Anderson to the discussion, since
he's the only strong proponent and user of logical pathnames I know.)

REMINDER ABOUT LOGICAL PATHNAMES (LPNs)

So, the CLHS says LPNs are case-converted to upper-case,
portably restricted to such upper-case characters,
and get translated to physical pathnames
in an implementation-dependent way.
On Unix, with its case-sensitive filesystems and lower-case conventions,
the useful thing is then downcasing names.

At least SBCL and CLISP follow both the standard
and the useful pathname mapping convention.
SBCL goes on to length to throw an error
when non-portable code tries to break
the standard restrictions on logical-pathnames;
CLISP will let you manually make-pathname a LPN
with lower-case or mixed-case characters, but
will still downcase them at the end
(the latest CLISP 2.49 also seems to not want to create
a logical pathname with parse-namestring).
CCL tries to make users happy by leaving the logical pathname host
case-insensitive (per the standard) but case-preserving,
and being case-sensitive in the rest of the pathname
(if you want upper-case, you know where to find it).
To collect and analyze the behavior of each of 14 implementations
is left as an exercise to the logical-pathname loving reader [M20].
To devise, document and get implementations to adopt a common behavior
that would be universally accepted by all is left as another exercise [50].

ASDF NAMING OF SYSTEMS

Similarly, when naming an ASDF system, to allow
to designate systems with symbols (CL legacy), which are case-converted,
yet map them to a unixy lower-case name, and still
allow systems with all kind of cases,
symbols are downcased whereas strings preserved.
Then the filesystem is queried with the resulting normalized string name
(see function coerce-name).

Now with its good old central-registry,
ASDF used to query each directory every time a system was requested.
This works great with logical pathnames, as it defers
all case handling to the last minute, and allows .asd files
to be loaded with a LPN as the *load-pathname*.
However, this was somewhat slow, and
it didn't scale to recursively searching directories,
and so came the habit of creating "link farms",
single directories with plenty of symlinks to adequate .asd files.
Of course, symlinks are both not so portable
(not very well supported in Windows, if at all, though
later versions of ASDF recognize Windows shortcuts as a substitute),
and a maintenance nightmare (unlike Macintosh aliases,
they are not automatically updated
when a system is installed, moved or deleted).
Therefore link farms were not a good interface to end-users.

For ASDF 2, I implemented a new way to manage system files:
the source-registry. It allows you to specify trees to search recursively
as well as single directories. Whether the registry is searched lazily
(when a system is requested) or eagerly (one the first time around) or
yet something else, was left unspecified. In my first implementation of it,
I built upon the previous central-registry, and at initialization time
I was looking for which subdirectories in the specified trees
did contain .asd files, then saved these in a list that I consulted
in the very same way as the central-registry.
(Note: the central registry is still there, and consulted first.)

However, DIRECTORY returns fully resolved TRUENAMEs, and
any portable way of searching inside subdirectories is doomed
to squash away logical pathnames. Currently, any use of :tree
in source-registry will resolve into physical pathnames (PPNs)
on most implementations, and always did.

However, entries with :directory used to preserve LPNs.
Not so with 2.014.7, where, prompted by a Quicklisp feature request,
I implemented eager caching of ASDF systems. So I query DIRECTORY
and save the results in a hash-table indexed by pathname-name.
The table is case-sensitive, to reflect the case-sensitive names of ASDF.
One consequence is that :directory entries do not preserve LPNs anymore.

Another more subtle consequence is that things may go wrong
if your filesystem is case-insensitive but case-preserving.
In the old way of doing things (still available with the central-registry),
you'd typically be looking for the file with lower-case name,
and you would find it even if named in different cases on disk.
With the old way, you'll record the name in its case mix,
and will never match it against the (lowercase) name.
So some systems that depend on this behavior will disappear.

POTENTIAL SOLUTIONS

An easy way out is to declare that ASDF from now on
shall be case-insensitive, using EQUALP to compare system names
and in hash-tables that cache system files.
Another way out is to declare that ASDF is still case sensitive,
and that the only case allowed is lower-case for physical filenames.
Any system that doesn't work with this new interpretation
probably didn't work portably with the old one, anyway.

A harder way out would be to assume case-sensitivity in the filesystem
(since some filesystems are case-sensitive, and any asd file that depends
on case-insensitivity is non-portable and deserves to lose),
and make extra effort when using DIRECTORY against logical pathnames
to always reconstitute LPNs from the PPNs given by directory,
and drop the reconstituted results if they don't resolve to the same thing.
But is it worth the pain?

Finally, I could do nothing, and assume that
people who go through the pain of setting up logical pathnames
before they run ASDF can just as well setup the *central-registry*
and have LPNs be recognized in the good old way.
If you use the source-registry, your LPNs will be squashed,
and nothing will break in the code since code works fine with PPNs,
just like most everyone use it, but your debug information
will be stored according to the PPN, not the LPN. Meh.

Zach (if you're still reading), do any systems in the wild
use anything but lower-case names for system files?

[ François-René ÐVB Rideau | Reflection&Cybernethics | http://fare.tunes.org ]
Two members of the Political Police salute a giant portrait of our Great Leader
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a sincere gaze pleeing into his colleagues' eyes.
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Pascal Costanza  
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 More options Jun 12 2011, 11:49 am
From: Pascal Costanza <p...@p-cos.net>
Date: Sun, 12 Jun 2011 17:49:11 +0200
Local: Sun, Jun 12 2011 11:49 am
Subject: Re: [Sbcl-devel] Logical pathnames vs ASDF & SBCL
Hi,

This is all very frustrating. With ASDF 1.x, everything worked fine and I have never encountered any issues. Since CL implementations "upgraded" to ASDF 2.x, things run into problems on a regular basis.

What is really annoying is that the ASDF 2.x documentation is misleading. *central-registry* is described as old-style and deprecated that is hopefully going away in the future, and logical pathnames are also described as old-style and better to be avoided. If I read the recent messages by Fare and James correctly, it turns out that if I had sticked to *central-registry* and switched to logical pathnames, everything would be fine and I wouldn't have had to waste time on a very frustrating experience.

Please take one or two steps back and try to see the global picture: Logical pathnames and *central-registry* have their quirks and complications, that is correct. But all you're doing is to replace this with an alternative that has again their own quirks and complications. So overall you're not making things easier, you're just replacing one difficult-to-use system with another difficult-to-use system. This is not a win, not for anybody.

ASDF is not the central focus of my work. It's a tool that is supposed to make my life easier, not harder. I want to contribute to the Common Lisp community by providing my own libraries, not by fighting a build tool.

I will try to switch to *central-registry* again. It seems promising that this could actually work in the mid run and not cause any further problems down the line. Please make sure that it stays that way.

Best,
Pascal

On 12 Jun 2011, at 02:25, Faré wrote:

--
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Faré  
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 More options Jun 13 2011, 12:29 am
From: Faré <fah...@gmail.com>
Date: Mon, 13 Jun 2011 00:29:03 -0400
Local: Mon, Jun 13 2011 12:29 am
Subject: Re: [Sbcl-devel] Logical pathnames vs ASDF & SBCL
On 12 June 2011 11:49, Pascal Costanza <p...@p-cos.net> wrote:
> Hi,

> This is all very frustrating. With ASDF 1.x, everything worked fine and I have never encountered any issues. Since CL implementations "upgraded" to ASDF 2.x, things run into problems on a regular basis.

I'm sorry you're running into problems. I could have done things
better. Yet, I believe ASDF 2 is a clear improvement over ASDF 1. I
also believe a lot of your problems come from your rash attitude in
dealing with adversity.

> What is really annoying is that the ASDF 2.x documentation is misleading. *central-registry* is described as old-style and deprecated that is hopefully going away in the future, and logical pathnames are also described as old-style and better to be avoided. If I read the recent messages by Fare and James correctly, it turns out that if I had sticked to *central-registry* and switched to logical pathnames, everything would be fine and I wouldn't have had to waste time on a very frustrating experience.

I still believe central-registry and logical pathnames are old style,
since they necessitate implementation-dependent configuration (i.e.
more buck) for results of more limited applicability (i.e. less bang).
I am unwilling to dig into each implementation's details and document
the 14 different ways to get things working this way.

For a less frustrating experience, you could communicate better and
earlier about your problems.

For instance, you apparently switched to logical pathnames after you
experienced a bug in the ASDF support for RMCL. If only you had
reported that my previous series of fixes to RMCL support still didn't
solve your issues, and kept pressing the issues, I would have provided
a solution then, rather than when Binghe reported the issue again a
few months afterwards.

> Please take one or two steps back and try to see the global picture: Logical pathnames and *central-registry* have their quirks and complications, that is correct. But all you're doing is to replace this with an alternative that has again their own quirks and complications. So overall you're not making things easier, you're just replacing one difficult-to-use system with another difficult-to-use system. This is not a win, not for anybody.

I believe I made things easier: no more per-implementation
configuration, no more attempts to badly documentation half of them.

...

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Pascal Costanza  
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 More options Jun 13 2011, 2:46 am
From: Pascal Costanza <p...@p-cos.net>
Date: Mon, 13 Jun 2011 08:46:52 +0200
Local: Mon, Jun 13 2011 2:46 am
Subject: Re: [Sbcl-devel] Logical pathnames vs ASDF & SBCL

On 13 Jun 2011, at 06:29, Faré wrote:

Your reactions to bug reports are either null, or very discouraging. I usually only get fixes or workarounds by people other than you. Instead I repeatedly hear from you that either I am doing something wrong, or that what I'm trying to do is deprecated, or legacy, or old-style, or whatever. Or you don't react at all (like with my _bug_ report that the documentation is misleading, which is the main reason why I switched from a working setup to a setup that doesn't work). Or like here, you react by saying that I'm not reporting problems properly, or not early enough, or whatever.

I don't get such reactions from any other library/tool maintainer!

You either support a feature, or you don't. Don't do this mixed bag of "I support it, but you're a loser if you use it."

The main reason why I'm having problems with ASDF 2.x is because it's alpha-quality software at best (you're still trying to figure out some very basic concepts, it seems to me), yet you don't even call it beta quality, but instead choose to call it 2.x, push it down everybody's throats, and turn a whole community into alpha testers who didn't volunteer to be guinea pigs in the first place.

I have used ASDF 1.x and it's central registry approach for years in almost all CL implementations available, and I have never encountered any problems with it. I have also used logical pathnames to some limited extent years ago, and my experience with those weren't even remotely as bad as with ASDF 2.x. When using them recently, for a few weeks they actually made something work that ASDF 2.x claims to support, but actually didn't really, until ASDF screwed it up again.

I'm not sure how to proceed from here. Communicating with you and reporting bugs doesn't seem to buy anything. If I had the choice I would just drop ASDF 2.x and go back to ASDF 1.x, but this doesn't seem a viable option. Or is it?

Pascal

...

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Faré  
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 More options Jun 13 2011, 9:17 am
From: Faré <fah...@gmail.com>
Date: Mon, 13 Jun 2011 09:17:09 -0400
Local: Mon, Jun 13 2011 9:17 am
Subject: Re: [Sbcl-devel] Logical pathnames vs ASDF & SBCL
> Your reactions to bug reports are either null, or very discouraging.

Which bug did you report that I didn't address?
There are archives, please show me.

> I usually only get fixes or workarounds by people other than you.

I'm glad you're getting support from others. Unhappily,
you won't get any from me unless you communicate with me.

> Instead I repeatedly hear from you that either I am doing something wrong, or that what I'm trying to do is deprecated, or legacy, or old-style, or whatever.

I never said anything was "deprecated".
central-registry and logical pathnames are very much supported.
I did say legacy and old-style indeed.
Which means they continue to work as they always did.
Robert Goldman and I even took pains to maintain and extend
the documentation on how to use them, to include
common usage, known pitfalls and some advanced features.
While it's not a lot of documentation, it's still more than was before.

> Or you don't react at all (like with my _bug_ report that the documentation is misleading, which is the main reason why I switched from a working setup to a setup that doesn't work). Or like here, you react by saying that I'm not reporting problems properly, or not early enough, or whatever.

As far as I can tell, the reason your setup didn't work
is because the MCL support had bitrotten.
My excuse for that is that I never had a chance to use a Mac.
As far as I know, I fixed all the issues I am aware of
— based on binghe's bug reports.
I never had a clear bug report from you.

> I don't get such reactions from any other library/tool maintainer!

My apologies. I obviously fail to communicate with you.
But communication is a two-way thing.
Maybe you can come down to my level.

> You either support a feature, or you don't. Don't do this mixed bag of "I support it, but you're a loser if you use it."

I support central-registry and logical pathnames within my limits.
I didn't touch the legacy configuration system.
It's working, it's stable. You can keep using it as you always did before.
It takes priority over the new source-registry.
If you're using these features, though,
you're not a loser: you're an advanced user;
your curse is that you have to take responsibility for that,
because lesser people such as I are unable to do it.
You already know more about logical pathnames than I do;
I'm ready to learn from you everything you'll tell me
about how to do things right about them.

> The main reason why I'm having problems with ASDF 2.x is because it's alpha-quality software at best (you're still trying to figure out some very basic concepts, it seems to me), yet you don't even call it beta quality, but instead choose to call it 2.x, push it down everybody's throats, and turn a whole community into alpha testers who didn't volunteer to be guinea pigs in the first place.

I called it 2.x to make it clear that there had been significant changes
since the first 1.x series, and that while compatibility is our goal,
we warn that there might be breakage in a few
formerly underspecified or non-portable corner cases,
or on platforms we don't have access to.

I indeed am trying to "push it down everybody's throats",
in other words I aim to satisfy everyone enough that they will adopt it.
I apologize if you're experiencing trouble and encourage you
to pick whichever legacy version you're more satisfied with,
if you're experiencing issues with mine.
I certainly didn't install ASDF 2.x on your machine.
Why did you even try to upgrade?
If you needed a bug fix or new feature, then maybe it's not totally useless.
If you just wanted to test it, then I thank you for testing:
you were the very first to try ASDF 2 on RMCL.

> I have used ASDF 1.x and it's central registry approach for years in almost all CL implementations available, and I have never encountered any problems with it. I have also used logical pathnames to some limited extent years ago, and my experience with those weren't even remotely as bad as with ASDF 2.x. When using them recently, for a few weeks they actually made something work that ASDF 2.x claims to support, but actually didn't really, until ASDF screwed it up again.

My only claim of support is that I will fix bugs that are reported to me.
I can't fix bugs that are not reported.
If you have an unusual setup, you have to explain
what you are doing, what is breaking, and how it is breaking.
I'm not going to remotely hack into your computer at night
to find out whether things are wrong and why.
I unhappily can't run batteries of test
on an implementation I don't have access to.

That said, yes, it might be useful to write unit tests
for the support of logical pathnames by the source-registry.
Patches welcome.

> I'm not sure how to proceed from here. Communicating with you and reporting bugs doesn't seem to buy anything. If I had the choice I would just drop ASDF 2.x and go back to ASDF 1.x, but this doesn't seem a viable option. Or is it?

I don't see why you believe that ASDF 1.x isn't a viable option.
Certainly, if you believe that ASDF 2.x doesn't bring anything valuable,
you should stick to ASDF 1.x. Of course, I won't be able to provide
support for it, but that shouldn't be an issue for you,
since my support seems of little value to you.

Best regards,

—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org
Fascists divide in two categories: the fascists and the anti-fascists
        — Ennio Flaiano

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Discussion subject changed to "[asdf-devel] Logical pathnames vs ASDF & SBCL" by Attila Lendvai
Attila Lendvai  
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 More options Jun 16 2011, 6:31 pm
From: Attila Lendvai <attila.lend...@gmail.com>
Date: Fri, 17 Jun 2011 00:31:59 +0200
Local: Thurs, Jun 16 2011 6:31 pm
Subject: Re: [Sbcl-devel] [asdf-devel] Logical pathnames vs ASDF & SBCL

> The main reason why I'm having problems with ASDF 2.x is
> because it's alpha-quality software at best (you're still trying
> to figure out some very basic concepts, it seems to me), yet
> you don't even call it beta quality, but instead choose to call
> it 2.x, push it down everybody's throats, and turn a whole
> community into alpha testers who didn't volunteer to be
> guinea pigs in the first place.

as people with positive opinion speak up much less, let me point out
here that i'm a happy user of ASDF2 from its early days.

it did require some work to follow it, but it made many things simpler
and more reliable in our dev setup and production environment (the
load order with underspecified dependencies using ASDF1 used to be
influenced by the filesystem order, seemingly not even randomly,
because errors consistently appeared when changes were pulled to
another computer. rmfasl didn't influence it. a real pain in the ass
when build fails on the production system after an upgrade...)

any form of backwards incompatibility, and upgrading in general, is a
pain, but we need to live with it because for now it's part of being a
software developer (it's solvable on the language/vm/devtool level,
but our ideas are mere vapour). i regularly unpull problematic patches
of random libraries, and ASDF is just one of them. luckily ASDF2 can
even properly upgrade itself now!

to me it's certainly an improvement over ASDF1.

thanks for all the work put into ASDF, both v1 and v2!

--
 attila

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Discussion subject changed to "Logical pathnames vs ASDF & SBCL" by Scott L. Burson
Scott L. Burson  
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 More options Jun 16 2011, 8:13 pm
From: "Scott L. Burson" <Sc...@sympoiesis.com>
Date: Thu, 16 Jun 2011 17:13:08 -0700
Local: Thurs, Jun 16 2011 8:13 pm
Subject: Re: [Sbcl-devel] Logical pathnames vs ASDF & SBCL

On Mon, Jun 13, 2011 at 6:17 AM, Faré <fah...@gmail.com> wrote:
> I don't see why you believe that ASDF 1.x isn't a viable option.

I'm not among those having trouble with ASDF v2, but I would just
point out that going back to v1 has been made rather unattractive by
the tremendous usefulness of Quicklisp, which AFAIK depends on v2.

-- Scott

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Zach Beane  
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 More options Jun 17 2011, 7:19 am
From: Zach Beane <x...@xach.com>
Date: Fri, 17 Jun 2011 07:19:04 -0400
Local: Fri, Jun 17 2011 7:19 am
Subject: Re: [Sbcl-devel] Logical pathnames vs ASDF & SBCL
"Scott L. Burson" <Sc...@sympoiesis.com> writes:

> On Mon, Jun 13, 2011 at 6:17 AM, Faré <fah...@gmail.com> wrote:
>> I don't see why you believe that ASDF 1.x isn't a viable option.

> I'm not among those having trouble with ASDF v2, but I would just
> point out that going back to v1 has been made rather unattractive by
> the tremendous usefulness of Quicklisp, which AFAIK depends on v2.

No, it doesn't.

When I started sharing Quicklisp, some implementations didn't ship ASDF
at all, so it made sense to bundle a copy and load it if
necessary. ASDF2 seemed like the reasonable thing to bundle.

The feature of ASDF2 that makes Quicklisp work better is implementation
FASL segregation enabled by default.

Zach

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