[bug#70065] [PATCH 4/6] gnu: chez-scheme: Update to 10.0.0.

[Skyler Ferris via Guix-patches via <guix-patches@gnu.org>]

Hi again! I stepped away from my desk to do something else and as often 
happens the answer came to me. I'll include full steps to reproduce the 
issue below, in order to build confidence in my explanation, but the 
TLDR is that your definition is correct and it was a problem on my end. 
Additionally, I confirmed that loko-scheme still builds and runs. I'll 
keep this situation in mind for future reviews. Thank you for all your 
hard work!

Explanation:

The loko.scm file was not recompiled so it searched chez.scm for a 
variable named chez-scheme-for-system, which is now a syntax 
transformer. But compiled files have already completed the expansion 
phase, so this means that a syntax transformer is invalid. This will not 
cause a problem for `guix pull` because guix rebuilds itself from 
scratch when it gets updated.

Reproduction:

1. Build the tree without patch 4/6 applied
    `guix shell -D guix -CPW -- make`
2. Apply the patch
    `git apply /path/to/patch`
3. Build the tree again
    `guix shell -D guix -CPW -- make`
4. Try to build loko-scheme
    `./pre-inst-env guix build loko-scheme`
5. Delete the compiled loko file
    `rm gnu/packages/loko.go`
6. Build the tree again
    `guix shell -D guix -CPW -- make`
7. Build loko-scheme
    `./pre-inst-env guix build loko-scheme`

On 3/31/24 07:35, Skyler Ferris wrote:
> On 3/30/24 15:49, Philip McGrath wrote:
>> I still don't understand why the deprecation definition isn't working. I
>> expected the expansion at the repl, and (chez-scheme-for-system)
>> expanded to (%chez-scheme-for-system/deprecated), which was defined by
>> the expansion of define-deprecated as:
>>
>>     (define %chez-scheme-for-system/deprecated
>>       (begin
>>         (lambda () chez-scheme)
>>         (lambda* (#:optional (system #f)) chez-scheme)))
>>
>> I guess, unless I figure something out or someone has a better
>> suggestion, I could just remove chez-scheme-for-system without
>> deprecation, but that seemed less friendly.
>
> So, I started poking at this and ran into something strange. I removed 
> the surrounding parentheses from chez-scheme-for-system in loko.scm, 
> and it gave me the expected error about an invalid package, where the 
> value was a procedure rather than a package. Which sounds like what I 
> would expect if it was working, except that it didn't work with the 
> parentheses. Then, after adding the parentheses back it stopped giving 
> me the error, even after running make again.
>
> I haven't worked with define-deprecated before. It's a macro, and I 
> know that the guile compiler misses recompiling macro dependencies 
> sometimes, so maybe it was a problem on my end with having mismatching 
> build artifacts. I'll try a clean build with these patches and a 
> simulated guix pull within the next couple of days (hopefully today), 
> and if those both work then the definition is probably correct.... but 
> I'd be more comfortable if we could explain exactly why that error 
> occurred. I'll also look more at the definitions, but I think it will 
> be a little difficult to be confident in any explanation if I can't 
> reproduce the error. Here's the full error output, in case it's 
> helpful to anyone:
>
> Backtrace:
> In ice-9/boot-9.scm:
>   1752:10 19 (with-exception-handler _ _ #:unwind? _ # _)
> In guix/ui.scm:
>     485:6 18 (_)
> In guix/scripts/build.scm:
>     711:5 17 (_)
> In srfi/srfi-1.scm:
>    673:15 16 (append-map #<procedure 7fef052ecdc0 at guix/scripts/b…> …)
>    586:17 15 (map1 ("x86_64-linux"))
> In guix/scripts/build.scm:
>    713:21 14 (_ _)
> In guix/store.scm:
>   1382:11 13 (map/accumulate-builds #<store-connection 256.100 7fef…> …)
>    1300:8 12 (call-with-build-handler #<procedure 7fef06f90990 at g…> …)
> In guix/scripts/build.scm:
>    667:16 11 (_ #<package loko-scheme@0.12.0 gnu/packages/loko.scm:3…>)
>    656:24 10 (_ #<package loko-scheme@0.12.0 gnu/packages/loko.scm:…> …)
> In guix/packages.scm:
>   1378:17  9 (supported-package? #<package loko-scheme@0.12.0 gnu/p…> …)
> In guix/memoization.scm:
>     101:0  8 (_ #<hash-table 7fef036b2120 0/31> #<package loko-sche…> …)
> In guix/packages.scm:
>   1356:39  7 (_)
>   1618:16  6 (package->bag _ _ _ #:graft? _)
>   1722:47  5 (thunk)
> In gnu/packages/loko.scm:
>     77:11  4 (native-inputs #<package loko-scheme@0.12.0 gnu/package…>)
>     77:11  3 (native-inputs _)
> In ice-9/boot-9.scm:
>   1685:16  2 (raise-exception _ #:continuable? _)
>   1685:16  1 (raise-exception _ #:continuable? _)
>   1685:16  0 (raise-exception _ #:continuable? _)
>
> ice-9/boot-9.scm:1685:16: In procedure raise-exception:
> Wrong type to apply: #<syntax-transformer chez-scheme-for-system>
>