bug#72365: srfi-64: test-on-bad-end-name-simple is not allowed to raise an exception

bug#72365: srfi-64: test-on-bad-end-name-simple is not allowed to raise an exception

[Tomas Volf]

Hello,

I think I found a bug in (srfi srfi-64) module shipped with GNU Guile.

The specification says the following about the simple test runner:

> Creates a new simple test-runner, that prints errors and a summary on the
> standard output port.

It does not mention that it can signal errors, so I believe the following should
just print to the terminal:

    (use-modules (srfi srfi-64))
    (test-on-bad-end-name-simple (test-runner-null) "x" "y")

However is signals an error instead:

    Backtrace:
    In ice-9/boot-9.scm:
      1752:10  6 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _)
    In unknown file:
               5 (apply-smob/0 #<thunk 7f6cf05a9300>)
    In ice-9/boot-9.scm:
        724:2  4 (call-with-prompt ("prompt") #<procedure 7f6cf05b6280 at ice-9/eval.scm:330:…> …)
    In ice-9/eval.scm:
        619:8  3 (_ #(#(#<directory (guile-user) 7f6cf05acc80>)))
    In ice-9/boot-9.scm:
       2836:4  2 (save-module-excursion #<procedure 7f6cf059d300 at ice-9/boot-9.scm:4393:3 ()>)
      4388:12  1 (_)
    In srfi/srfi-64/testing.scm:
       375:14  0 (test-on-bad-end-name-simple _ _ _)

    srfi/srfi-64/testing.scm:375:14: In procedure test-on-bad-end-name-simple:
    test-end x does not match test-begin y

Have a nice day
Tomas Volf

bug#72365: srfi-64: test-on-bad-end-name-simple is not allowed to raise an exception

[Taylan Kammer]

On 30.07.2024 21:51, Tomas Volf wrote:
> Hello,
>
> I think I found a bug in (srfi srfi-64) module shipped with GNU Guile.

Hi Tomas,

Thanks for stress-testing the SRFI 64 spec & implementation and reporting all these discrepancies. :-)

Firstly, to reiterate some things I've already mentioned in the thread on bug 71300, just so it goes on record here as well:

I have a SRFI 64 implementation of my own. I hope Guile will switch to it eventually because I find the upstream reference implementation to be somewhat unpleasant to work with. (It's monolithic, and not the cleanest code.)

Until then, my implementation can be used by following these steps:

1. Cloning this repo:

    https://codeberg.org/taylan/scheme-srfis/

2. Running Guile like so:

    GUILE_LOAD_PATH=/path/to/scheme-srfis/guile-srfi-64 guile

(Replacing /path/to/scheme-srfis with the actual path to wherein the repo was cloned, of course.)

Then, loading SRFI-64 the regular way should load my implementation rather than the one that ships with Guile (which is the reference implementation from the SRFI author).

I'll respond to your reports one by one, treating them like bug reports towards my own implementation, since it was originally derived from the reference implementation and has probably inherited some of the bugs. Unfortunately, I'm not motivated to work on the implementation that's in Guile, because I find it too cumbersome to navigate its code and the unclean coding practices too distracting.

> The specification says the following about the simple test runner:
>
>> Creates a new simple test-runner, that prints errors and a summary on the
>> standard output port.
> It does not mention that it can signal errors, so I believe the following should
> just print to the terminal:
>
>     (use-modules (srfi srfi-64))
>     (test-on-bad-end-name-simple (test-runner-null) "x" "y")
>
> However is signals an error instead:
>
>     Backtrace:
>     In ice-9/boot-9.scm:
>       1752:10  6 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _)
>     In unknown file:
>                5 (apply-smob/0 #<thunk 7f6cf05a9300>)
>     In ice-9/boot-9.scm:
>         724:2  4 (call-with-prompt ("prompt") #<procedure 7f6cf05b6280 at ice-9/eval.scm:330:…> …)
>     In ice-9/eval.scm:
>         619:8  3 (_ #(#(#<directory (guile-user) 7f6cf05acc80>)))
>     In ice-9/boot-9.scm:
>        2836:4  2 (save-module-excursion #<procedure 7f6cf059d300 at ice-9/boot-9.scm:4393:3 ()>)
>       4388:12  1 (_)
>     In srfi/srfi-64/testing.scm:
>        375:14  0 (test-on-bad-end-name-simple _ _ _)
>
>     srfi/srfi-64/testing.scm:375:14: In procedure test-on-bad-end-name-simple:
>     test-end x does not match test-begin y

The spec is very sparse on what the simple test runner does, so I'm not sure if the intention is to imply that it does nothing other than what's stated.

In one case, the reference implementation clearly violates the specification: The simple test runner uses the `aux` field which the spec claims it doesn't use. (My implementation fixes this.) However, in this case it's not that clear-cut.

In this case, I think raising an error is good default behavior, since the mismatched end name indicates a problem with the test suite itself rather than the code being tested. If it poses a problem to the user, one can override that callback with the `test-runner-on-bad-end-name!` setter.

What do you think?

- Taylan

bug#72365: srfi-64: test-on-bad-end-name-simple is not allowed to raise an exception

[Tomas Volf]

[-- Attachment #1: Type: text/plain, Size: 6762 bytes --]

Taylan Kammer <taylan.kammer@gmail.com> writes:

Hi,

sorry for taking so long to respond to your comments, work has been bit
busy lately.  I really appreciate you looking at them and validating
and/or challenging my conclusions.

> On 30.07.2024 21:51, Tomas Volf wrote:
>> Hello,
>>
>> I think I found a bug in (srfi srfi-64) module shipped with GNU Guile.
>
> Hi Tomas,
>
> Thanks for stress-testing the SRFI 64 spec & implementation and
> reporting all these discrepancies. :-)

No problem, it was necessary during implementing my own version of
SRFI-64.  The full test suite is available as part of my library[2], the
runner[3] is quite simple, so using it to test your implementation
should be fairly easy.

I think there are few more bugs than I reported, I lost the willpower to
do the rest somewhere on the way. :/

2: https://git.wolfsden.cz/guile-wolfsden/tree/tests/srfi-64
3: https://git.wolfsden.cz/guile-wolfsden/tree/build-aux/srfi64test-driver.scm

>
> Firstly, to reiterate some things I've already mentioned in the thread on bug 71300, just so it goes on record here as well:
>
> I have a SRFI 64 implementation of my own. I hope Guile will switch to it
> eventually because I find the upstream reference implementation to be somewhat
> unpleasant to work with. (It's monolithic, and not the cleanest code.)

I plan to attempt to upstream my version as well, so I guess it is a
race :)

>
> Until then, my implementation can be used by following these steps:
>
> 1. Cloning this repo:
>
>     https://codeberg.org/taylan/scheme-srfis/
>
> 2. Running Guile like so:
>
>     GUILE_LOAD_PATH=/path/to/scheme-srfis/guile-srfi-64 guile
>
> (Replacing /path/to/scheme-srfis with the actual path to wherein the repo was cloned, of course.)
>
> Then, loading SRFI-64 the regular way should load my implementation
> rather than the one that ships with Guile (which is the reference
> implementation from the SRFI author).

You can find my version here[0].  If you do not use Guix, building from
tarball[1] might be easier.  Contrary to your version, mine is available
as (wolfsden srfi srfi-64).

0: https://git.wolfsden.cz/guile-wolfsden/
1: https://wolfsden.cz/project/guile-wolfsden.html

>
> I'll respond to your reports one by one, treating them like bug reports towards
> my own implementation, since it was originally derived from the reference
> implementation and has probably inherited some of the bugs.

You are braver than me.  After few days of staring at the reference
implementation (in Guile), I just said "nope" and wrote a new one from
scratch.

> Unfortunately, I'm not motivated to work on the implementation that's
> in Guile, because I find it too cumbersome to navigate its code and
> the unclean coding practices too distracting.

While in principle I agree, let us not be too harsh, the implementation
is really old.  I assume coding practices available at the time to
achieve portability were bit different.  The implementation even
considers SRFI-9 optional, these days I think that would be considered
bit absurd.

>
>> The specification says the following about the simple test runner:
>>
>>> Creates a new simple test-runner, that prints errors and a summary on the
>>> standard output port.
>> It does not mention that it can signal errors, so I believe the following should
>> just print to the terminal:
>>
>>     (use-modules (srfi srfi-64))
>>     (test-on-bad-end-name-simple (test-runner-null) "x" "y")
>>
>> However is signals an error instead:
>>
>>     Backtrace:
>>     In ice-9/boot-9.scm:
>>       1752:10  6 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _)
>>     In unknown file:
>>                5 (apply-smob/0 #<thunk 7f6cf05a9300>)
>>     In ice-9/boot-9.scm:
>>         724:2  4 (call-with-prompt ("prompt") #<procedure 7f6cf05b6280 at ice-9/eval.scm:330:…> …)
>>     In ice-9/eval.scm:
>>         619:8  3 (_ #(#(#<directory (guile-user) 7f6cf05acc80>)))
>>     In ice-9/boot-9.scm:
>>        2836:4  2 (save-module-excursion #<procedure 7f6cf059d300 at ice-9/boot-9.scm:4393:3 ()>)
>>       4388:12  1 (_)
>>     In srfi/srfi-64/testing.scm:
>>        375:14  0 (test-on-bad-end-name-simple _ _ _)
>>
>>     srfi/srfi-64/testing.scm:375:14: In procedure test-on-bad-end-name-simple:
>>     test-end x does not match test-begin y
>
> The spec is very sparse on what the simple test runner does, so I'm
> not sure if the intention is to imply that it does nothing other than
> what's stated.

I am not sure how to read the spec regarding this.  But in my reading

>>> Creates a new simple test-runner, that prints errors and a summary
>>> on the standard output port.

is clear enough.  Same way I would think (for example) reporting a
telemetry (e.g. on number of tests executed) would violate the spec.

>
> In one case, the reference implementation clearly violates the specification:
> The simple test runner uses the `aux` field which the spec claims it doesn't
> use. (My implementation fixes this.) However, in this case it's not that
> clear-cut.
>
> In this case, I think raising an error is good default behavior, since the
> mismatched end name indicates a problem with the test suite itself rather than
> the code being tested. If it poses a problem to the user, one can override that
> callback with the `test-runner-on-bad-end-name!` setter.
>
> What do you think?

I agree that raising an error is good behavior.  However I do not think
that on-bad-end-name-function is a place where to do it.  In my opinion
the name mismatch is a hard error, in my implementation subclass of
&programming-error[4].  If I am writing new test runner, the
specification does not mention that raising the error is *my*
responsibility, just that test-end will signal an error.

To rephrase that: test-end is mandated to signal error, but custom test
runner has no provision requiring it to do it in
on-bad-end-name-function.  Hence I believe test-end needs to be the one
to signal the error.

However!  That does not make on-bad-end-name-function useless.  The
specification does not mandate *how* the error signaled by test-end
should look like, hence there is no *portable* way to detect it.  Custom
runner, if it needs to report name mismatch specially, can just produce
specific log line in the callback (or even signal its own exception
first before test-end does).

4: https://git.wolfsden.cz/guile-wolfsden/tree/wolfsden/srfi/srfi-64.scm#n960

Let me know what you think.

Have a nice day,
Tomas

-- 
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 853 bytes --]

bug#72365: srfi-64: test-on-bad-end-name-simple is not allowed to raise an exception

[Taylan Kammer]

[-- Attachment #1: Type: text/plain, Size: 7617 bytes --]

On 02.10.2024 14:28, Tomas Volf wrote:
> Taylan Kammer <taylan.kammer@gmail.com> writes:
>
> Hi,
>
> sorry for taking so long to respond to your comments, work has been bit
> busy lately.

I took two months whereas you took two days, so I'm not going to complain. :D


>> On 30.07.2024 21:51, Tomas Volf wrote:
>>> Hello,
>>>
>>> I think I found a bug in (srfi srfi-64) module shipped with GNU Guile.
>> Hi Tomas,
>>
>> Thanks for stress-testing the SRFI 64 spec & implementation and
>> reporting all these discrepancies. :-)
> No problem, it was necessary during implementing my own version of
> SRFI-64.  The full test suite is available as part of my library[2], the
> runner[3] is quite simple, so using it to test your implementation
> should be fairly easy.
>
> I think there are few more bugs than I reported, I lost the willpower to
> do the rest somewhere on the way. :/
>
> 2: https://git.wolfsden.cz/guile-wolfsden/tree/tests/srfi-64
> 3: https://git.wolfsden.cz/guile-wolfsden/tree/build-aux/srfi64test-driver.scm

Do I understand correctly that this is an additional test suite for testing SRFI-64 itself? Like the "meta test suite" shipped with SRFI-64?

Is there a brief description somewhere on how to run it with Guile? Would be really neat if I can use it to further test my implementation.


>> Firstly, to reiterate some things I've already mentioned in the thread on bug 71300, just so it goes on record here as well:
>>
>> I have a SRFI 64 implementation of my own. I hope Guile will switch to it
>> eventually because I find the upstream reference implementation to be somewhat
>> unpleasant to work with. (It's monolithic, and not the cleanest code.)
> I plan to attempt to upstream my version as well, so I guess it is a
> race :)
>
>> Until then, my implementation can be used by following these steps:
>>
>> 1. Cloning this repo:
>>
>>     https://codeberg.org/taylan/scheme-srfis/
>>
>> 2. Running Guile like so:
>>
>>     GUILE_LOAD_PATH=/path/to/scheme-srfis/guile-srfi-64 guile
>>
>> (Replacing /path/to/scheme-srfis with the actual path to wherein the repo was cloned, of course.)
>>
>> Then, loading SRFI-64 the regular way should load my implementation
>> rather than the one that ships with Guile (which is the reference
>> implementation from the SRFI author).
> You can find my version here[0].  If you do not use Guix, building from
> tarball[1] might be easier.  Contrary to your version, mine is available
> as (wolfsden srfi srfi-64).
>
> 0: https://git.wolfsden.cz/guile-wolfsden/
> 1: https://wolfsden.cz/project/guile-wolfsden.html

Your implementation seems written specifically with Guile in mind, which is a big plus I guess.

Mine was written with R7RS in mind, and has compatibility shims for Guile as well as other Scheme implementations like Kawa (shims adopted from the original implementation). This makes it hacky in some parts, like when it comes to how it gathers source code information for file name & line number reporting. It also lacks docstrings, doesn't make use of Guile features like `define*` and so on...

If the quality of the implementations is the same or higher, in terms of observable behavior, then it should be preferred for Guile, I think. If I find the time, I'll see if I can use your implementation to run some of my test suites, like the bytestructures test suite, and report if I notice any issues.


>> Unfortunately, I'm not motivated to work on the implementation that's
>> in Guile, because I find it too cumbersome to navigate its code and
>> the unclean coding practices too distracting.
> While in principle I agree, let us not be too harsh, the implementation
> is really old.  I assume coding practices available at the time to
> achieve portability were bit different.  The implementation even
> considers SRFI-9 optional, these days I think that would be considered
> bit absurd.

That's true. I don't mean to insult the author or anything. It is what it is.

>> The spec is very sparse on what the simple test runner does, so I'm
>> not sure if the intention is to imply that it does nothing other than
>> what's stated.
> I am not sure how to read the spec regarding this.  But in my reading
>
>>>> Creates a new simple test-runner, that prints errors and a summary
>>>> on the standard output port.
> is clear enough.  Same way I would think (for example) reporting a
> telemetry (e.g. on number of tests executed) would violate the spec.
>
>> In one case, the reference implementation clearly violates the specification:
>> The simple test runner uses the `aux` field which the spec claims it doesn't
>> use. (My implementation fixes this.) However, in this case it's not that
>> clear-cut.
>>
>> In this case, I think raising an error is good default behavior, since the
>> mismatched end name indicates a problem with the test suite itself rather than
>> the code being tested. If it poses a problem to the user, one can override that
>> callback with the `test-runner-on-bad-end-name!` setter.
>>
>> What do you think?
> I agree that raising an error is good behavior.  However I do not think
> that on-bad-end-name-function is a place where to do it.  In my opinion
> the name mismatch is a hard error, in my implementation subclass of
> &programming-error[4].  If I am writing new test runner, the
> specification does not mention that raising the error is *my*
> responsibility, just that test-end will signal an error.
>
> To rephrase that: test-end is mandated to signal error, but custom test
> runner has no provision requiring it to do it in
> on-bad-end-name-function.  Hence I believe test-end needs to be the one
> to signal the error.

Makes sense I guess. I've generally tried to imitate the reference implementation's behavior as closely as possible in such matters, worrying that there might be code out there that relies on its various quirks, but maybe I'm being too paranoid.

I don't have a strong opinion either way. The number of people, who want to write a test runner that does something special on bad-end-name (something other than raise an error), is probably very small.

- Making `test-end` itself raise an error would probably be most convenient, so test runner authors don't have to take care of it.

- But if `test-end` doesn't do it, it's not a big deal either IMO, because all they would need to do is to call `(test-runner-on-bad-end-name! my-runner test-on-bad-end-name-simple)` to make their custom runner raise an error as well. (And, if they want to do something before, they can use a procedure that ends with the call `(test-on-bad-end-name-simple ...)`.)

The latter is my preference, because enabling the behavior via a single line of code is easy, whereas disabling it would be difficult / impossible if `test-end` were to be hardcoded to raise an error. But if a SRFI-64 implementation made its `test-end` always raise an error, it probably wouldn't anyone in practice, so I wouldn't see it as a real problem.


> However!  That does not make on-bad-end-name-function useless.  The
> specification does not mandate *how* the error signaled by test-end
> should look like, hence there is no *portable* way to detect it.  Custom
> runner, if it needs to report name mismatch specially, can just produce
> specific log line in the callback (or even signal its own exception
> first before test-end does).
>
> 4: https://git.wolfsden.cz/guile-wolfsden/tree/wolfsden/srfi/srfi-64.scm#n960
>
> Let me know what you think.

Right, it doesn't make it useless per se. It could still be called before `test-end` raises an error.


> Have a nice day,
> Tomas

Likewise!

- Taylan

[-- Attachment #2: Type: text/html, Size: 10896 bytes --]

bug#72365: srfi-64: test-on-bad-end-name-simple is not allowed to raise an exception

[Tomas Volf]

Taylan Kammer <taylan.kammer@gmail.com> writes:

> Do I understand correctly that this is an additional test suite for
> testing SRFI-64 itself? Like the "meta test suite" shipped with
> SRFI-64?

Yes, exactly.  Vast majority of the tests are just derived from the
specification, with few non-portable written just for my implementation,
but those can be turned off.

>
> Is there a brief description somewhere on how to run it with Guile?
> Would be really neat if I can use it to further test my
> implementation.

It is not hard, but at the same time the test suite is not really
stand-alone, so the instructions will be bit hackish.

1. Download https://files.wolfsden.cz/releases/guile-wolfsden/guile-wolfsden-0.0.1.tar.gz
2. Unpack it.
3. Open `build-aux/srfi64test-driver.scm'.
4. On line 35 replace 'wolfsden with 'guile.
5. Open `Makefile.am'.
6. Delete lines 17-19 (assignment to `TESTS' variable).
7. Open `tests/srfi-64/local.mk'.
8. On line 4 change `TESTS +=' to `TESTS ='.
9. Build the project and run the tests:

    $ autoreconf -fvi
    $ ./configure --disable-doc-snarf
    $ make
    $ make check

Due to step 4. only portable (== written based on specification) tests
will run, and they will run against (srfi srfi-64).  Since you library
is available as that module, just make sure it is on the load path.
When I follow the steps, I get:

    # TOTAL: 340
    # PASS:  265
    # SKIP:  36
    # XFAIL: 0
    # FAIL:  39
    # XPASS: 0
    # ERROR: 0

You should get less FAILs I guess (since you have fixed many problems
already, and some you did not even have).

I am sure you will dispute some of those tests.  ^_^

>> You can find my version here[0].  If you do not use Guix, building from
>> tarball[1] might be easier.  Contrary to your version, mine is available
>> as (wolfsden srfi srfi-64).
>>
>> 0: https://git.wolfsden.cz/guile-wolfsden/
>> 1: https://wolfsden.cz/project/guile-wolfsden.html
>
> Your implementation seems written specifically with Guile in mind,
> which is a big plus I guess.

Yes, I decided to write my version in as-readable manner as possible
(well, at least I hope the code is readable), at the cost of
portability.  Since I have seen what portability did to (srfi srfi-64).

> If the quality of the implementations is the same or higher, in terms of
> observable behavior, then it should be preferred for Guile, I think. If I find
> the time, I'll see if I can use your implementation to run some of my test
> suites, like the bytestructures test suite, and report if I notice any
> issues.

Oh, that would be much appreciated.  I did test my version against
Guix's test suite (and it revealed 4 bugs in Guix's tests) and none in
my library, so I hope results for your project would be similar.

>>> In one case, the reference implementation clearly violates the specification:
>>> The simple test runner uses the `aux` field which the spec claims it doesn't
>>> use. (My implementation fixes this.) However, in this case it's not that
>>> clear-cut.
>>>
>>> In this case, I think raising an error is good default behavior, since the
>>> mismatched end name indicates a problem with the test suite itself rather than
>>> the code being tested. If it poses a problem to the user, one can override that
>>> callback with the `test-runner-on-bad-end-name!` setter.
>>>
>>> What do you think?
>> I agree that raising an error is good behavior.  However I do not think
>> that on-bad-end-name-function is a place where to do it.  In my opinion
>> the name mismatch is a hard error, in my implementation subclass of
>> &programming-error[4].  If I am writing new test runner, the
>> specification does not mention that raising the error is *my*
>> responsibility, just that test-end will signal an error.
>>
>> To rephrase that: test-end is mandated to signal error, but custom test
>> runner has no provision requiring it to do it in
>> on-bad-end-name-function.  Hence I believe test-end needs to be the one
>> to signal the error.
>
> Makes sense I guess. I've generally tried to imitate the reference
> implementation's behavior as closely as possible in such matters, worrying that
> there might be code out there that relies on its various quirks, but maybe I'm
> being too paranoid.

I tried to not use reference implementation that much, and instead
relied on the specification.  It was slow and painful process.

> I don't have a strong opinion either way. The number of people, who want to
> write a test runner that does something special on bad-end-name (something other
> than raise an error), is probably very small.

I definitely agree on this one.

>
> - Making `test-end` itself raise an error would probably be most convenient, so test runner authors don't have to take care of it.
>
> - But if `test-end` doesn't do it, it's not a big deal either IMO, because all
> they would need to do is to call `(test-runner-on-bad-end-name! my-runner
> test-on-bad-end-name-simple)` to make their custom runner raise an error as
> well. (And, if they want to do something before, they can use a procedure that
> ends with the call `(test-on-bad-end-name-simple ...)`.)
>
> The latter is my preference, because enabling the behavior via a single line of
> code is easy, whereas disabling it would be difficult / impossible if `test-end`
> were to be hardcoded to raise an error. But if a SRFI-64 implementation made its
> `test-end` always raise an error, it probably wouldn't anyone in practice, so I
> wouldn't see it as a real problem.

I still think test-end itself raising is what specification mandates
(whether it *should* mandate it is a different question :) ), however I
agree, I also am skeptical anyone's code actually cares either way.

Tomas

-- 
There are only two hard things in Computer Science:
cache invalidation, naming things and off-by-one errors.