Upgrade to GAP 4.10

[nthiery]

GAP 4.9 comes with a completely rewritten build system that will simplify our packaging. In particular, libGAP no longer needs to be a separate package.

What the branch does:

• Remove the libgap spkg

• Update the gap spkg to the new build system and build and install libgap

• Replace gap.shi.patch by a plain gap startup script for Sage

Rationale: GAP used to provide a startup shell script. The GAP devs are in the process of getting rid of it and provide a very minimal one. They recommend to just write our own rather than patching it.

• Update a few doctests w.r.t. changes of output of some GAP functions

• Possibly controversial: The new libgap currently *does not come* with symbol rewriting (foobar -> libGAP_foobar). This avoids messing around with GAP's sources; in particular opening the door for using a stock GAP from the OS distribution. However there always is a risk of name conflict. And indeed, GAP's constants (actually cpp macros) T_INT, T_FLOAT, ... conflict with Python's constants. This is currently worked around by forcing the inclusion of Python's structmember.h before the gap headers.

Something similar was started by Volker at #19915.

• Removes configure.patch: it was patching configure for better GMP detection under Cygwin (#13954). This should not be needed anymore with the new build system and use of --with-gmp. If it is, upstream asked for it to be reported and they will fix it.

• Revert #19726 (not needed anymore)

Status: currently broken - crashes deep inside GAP error handling system after few simple commands.

Basic tests on libgap:

sage: libgap.eval("GAPInfo.Version")
sage: libgap.DihedralGroup(10).CharacterTable()
CharacterTable( <pc group of size 10 with 2 generators> )
sage: libgap.Group(libgap.eval("[(1,2,3),(1,2)]")).Size()
6

Running most relevant tests:

sage -tp 8 sage/groups sage/libs/gap

Current status: lots of errors

Testing packages with dynamic loading (e.g. IO):

Install IO:

cd $SAGE/local/gap/latest/pkg
wget http://www.gap-system.org/pub/gap/gap4/tar.gz/packages/io-4.4.6.tar.gz
tar xvf /tmp/io-4.4.6.tar.gz
mv io-4.4.6 io
cd io
./configure
make

Test it locally:

cd ../..
./gap -l .
gap> LoadPackage("IO");
true

This does not yet work:

sage: libgap.LoadPackage("IO")
ValueError: libGAP: Error, module '/opt/sage-git/local/gap/latest/pkg/io/bin/x86_64-pc-linux-gnu-gcc-default64/io.so' not found

This should be fixed once GAP's gap binary is built on top of libgap. See: ​https://github.com/markuspf/gap/issues/1.

Note:

• Max Horn reviewed the list of GAP symbols we use in Sage; some have already changed in 4.9. See this ​pad for notes.

Tarball: ​https://www.gap-system.org/pub/gap/gap-4.10/tar.bz2/gap-4.10.0.tar.bz2

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​1c645e0	#22626: remove GAP's symbol prefixing in libgap: libGAP_Foo -> Foo
​1ecc67b	#22626: doctest update w.r.t. minor changes of output in GAP
​e8ebbca	#22626: GMP detection patch for cygwin should not be needed anymore
​fd65b06	#22626: Remove libgap spkg
​9511733	#22626: replace patch for GAP's startup script template in favor of a custom script
​550625e	#22626: remove GAP's symbol prefixing in libgap: libGAP_Foo -> Foo, and workaround GAP <-> Python symbol conflict
​a9c859c	#22626: updated gap spkg w.r.t. GAP's devel version and its new build system; also include compilation and installation of libgap
​3011ac0	Merge branch 'develop' into t/22626/upgrade_to_gap_4_9

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​234c54b

#22626: revert #19726 as it won't be needed for gap 4.9

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​b301e4c	#22626: ReST fix
​431845f	#22626: better work around for the GAP-Python name clash on T_INT, ...

[nthiery]

New commits:

​b301e4c	#22626: ReST fix
​431845f	#22626: better work around for the GAP-Python name clash on T_INT, ...

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​7c04025

22626: document the work around for the GAP-Python name clash on T_INT, ...

[fbissey]

So if I understand the mechanics involved, at the moment you have to configure and install gap. Then clean and configure and install for libgap. So it is still behaving like "two packages" with the same source code. Do we have an idea on when we'll have just have gap linking on libgap which would also solve this particular problem?

[nthiery]

Salut François,

Replying to fbissey:

So if I understand the mechanics involved, at the moment you have to configure and install gap. Then clean and configure and install for libgap. So it is still behaving like "two packages" with the same source code.

Exactly.

Do we have an idea on when we'll have just have gap linking on libgap which would also solve this particular problem?

The GAP developers are well aware of that and planning to implement it. They have not yet done yet just to be more incremental; their new build system is a big PR already :-) I would assume that this will be done before GAP 4.9 which they are planning for a couple months from now.

See: ​https://github.com/markuspf/gap/issues/2

Btw: feel free to comment / expand on the list there. I'll advertise this issue for additional feedback on the sage-packaging mailing list.

[jdemeyer]

Replying to fbissey:

So if I understand the mechanics involved, at the moment you have to configure and install gap. Then clean and configure and install for libgap. So it is still behaving like "two packages" with the same source code.

For this reason, I wonder why you didn't keep the separation GAP + libGAP in Sage too. If it effectively behaves as two packages, it seems more natural to keep it as two packages in Sage too. Imagine for example that we need to patch GAP but not libGAP or conversely, that would be harder with the current approach. That being said, this is mostly bikeshedding. So, if the current setup works well, there might be no reason to change it.

[dimpase]

Replying to jdemeyer:

Replying to fbissey:

So if I understand the mechanics involved, at the moment you have to configure and install gap. Then clean and configure and install for libgap. So it is still behaving like "two packages" with the same source code.

For this reason, I wonder why you didn't keep the separation GAP + libGAP in Sage too. If it effectively behaves as two packages, it seems more natural to keep it as two packages in Sage too. Imagine for example that we need to patch GAP but not libGAP or conversely, that would be harder with the current approach. That being said, this is mostly bikeshedding. So, if the current setup works well, there might be no reason to change it.

Two completely separate packages would also mean that gap_packages should come in two different flavours, etc. I'd rather keep it simple and do not multiply these instances (but rather hope that libGAP will support all of GAP packages soon).

[jdemeyer]

Replying to dimpase:

Two completely separate packages would also mean that gap_packages should come in two different flavours, etc.

So, you are saying that we need to install gap_packages twice too? Once for GAP and once for libGAP?

[nthiery]

Replying to jdemeyer:

For this reason, I wonder why you didn't keep the separation GAP + libGAP in Sage too.

I wanted to experiment with how far we were from having a proper single package, so as to give early feedback to the gap developers on any sticking points. And indeed, linking gap to libgap is basically the only sticking point. Since this point will be most likely resolved by the time this ticket gets merged in, we might as well shoot directly for the "right thing".

[dimpase]

Replying to jdemeyer:

Replying to dimpase:

Two completely separate packages would also mean that gap_packages should come in two different flavours, etc.

So, you are saying that we need to install gap_packages twice too? Once for GAP and once for libGAP?

no, not at all---I mean to say that there exist GAP packages (not part of Sage ATM) that break libGAP now. As some of these packages are very useful, it's important to have this fixed (but not at expense of having 2 separate gap_packages).

[nthiery]

Replying to dimpase:

As some of these packages are very useful, it's important to have this fixed

YES. In fact that is my main motivation to work on the libgap integration: I badly want to use Semigroups that requires IO! We went through the details with Markus and Max, and the shared aim is indeed to have this resolved with the upgrade to 4.9.

[jdemeyer]

Is there any news here?

[slelievre]

GAP 4.9.0, a beta release for GAP 4.9, has been released.

This means we can start working on building Sage with it.

• Release notes: ​https://github.com/gap-system/gap/wiki/GAP-4.9-release-notes

[dimpase]

Do you know if they now provide a replacement for libGAP?

[slelievre]

Cc-ing @alexk and @markuspf.

[nthiery]

Replying to dimpase:

Do you know if they now provide a replacement for libGAP?

In principle yes: the branch I posted here last April was using their stock alpha version. Now the next step is to revive the branch and adapt it if needed.

I can work on this, but probably not at once. Any volunteer to take over welcome.

Markus: do you foresee any major changes in how GAP's lib is to be built that could affect what I was doing last April?

[dimpase]

I just noticed that in 4.9 smallgrps and transgrps are released under a GPL-compatible license. This is great! We really should make them (i.e. database_gap) standard Sage package, and do away with the extra hurdle of having database_gap optional.

[jdemeyer]

If you're willing to wait 2 months, this might be a good task for the Cernay workshop ​https://github.com/OpenDreamKit/OpenDreamKit/issues/251

[nthiery]

Replying to jdemeyer:

If you're willing to wait 2 months, this might be a good task for the Cernay workshop ​https://github.com/OpenDreamKit/OpenDreamKit/issues/251

Yes indeed; it will be helpful to have GAP people under hand. I may just become impatient before that for some research project of mine, in which case I'll have a head start :-)

[nthiery]

Replying to dimpase:

I just noticed that in 4.9 smallgrps and transgrps are released under a GPL-compatible license. This is great! We really should make them (i.e. database_gap) standard Sage package, and do away with the extra hurdle of having database_gap optional.

Yes! I can't wait for all the simplifications this will bring to us!

[jdemeyer]

Replying to fbissey:

So if I understand the mechanics involved, at the moment you have to configure and install gap. Then clean and configure and install for libgap. So it is still behaving like "two packages".

With the past and future modifications to the Sage build system in mind, I now object more strongly than before to treating two separate packages (GAP + libGAP) as one package.

The reason is that we now try to separate the build and install stages of packages. But that is incompatible with the recipe here of first "build and install GAP" and then "build and install libGAP".

[jdemeyer]

For an example of two Sage packages with the same sources, see gcc and gfortran. IMHO, you should do the same for GAP and libGAP (unless they are merged upstream but my impression is that this has not happened yet).

[fbissey]

Replying to jdemeyer:

Replying to fbissey:

So if I understand the mechanics involved, at the moment you have to configure and install gap. Then clean and configure and install for libgap. So it is still behaving like "two packages".

With the past and future modifications to the Sage build system in mind, I now object more strongly than before to treating two separate packages (GAP + libGAP) as one package.

The reason is that we now try to separate the build and install stages of packages. But that is incompatible with the recipe here of first "build and install GAP" and then "build and install libGAP".

Hopefully we will be getting something more serious at final release time, like with pari where you build libpari and then the gp executable. That would be the ideal scenario where it is really one package. Have to see how far they have gone with 4.9.

[jdemeyer]

A lot of changes on this ticket (also the changes likely to lead to merge conflicts) are related to the unprefixing of libGAP symbols. To ease development, maybe we should try to do that separately from the upgrade to GAP 4.9.

I was thinking to do something like #19915 but changing only the Sage source code (not libGAP) and undoing the prefixing with macros like #define SomeGapFunction libGAP_SomeGapFunction. What do you think?

[dimpase]

there is also libgap unprefixing in Python/Cython? that has to be done. Perhaps separating these from C level unprefixing would help making it smoother.

[jdemeyer]

Replying to dimpase:

there is also libgap unprefixing in Python/Cython? that has to be done. Perhaps separating these from C level unprefixing would help making it smoother.

Yes, that is what I meant. Creating a separate ticket for unprefixing only at the Cython level by using macros to translate between the unprefixed names in Cython and the prefixed names in libGAP.

[dimpase]

Replying to jdemeyer:

Replying to dimpase:

there is also libgap unprefixing in Python/Cython? that has to be done. Perhaps separating these from C level unprefixing would help making it smoother.

Yes, that is what I meant. Creating a separate ticket for unprefixing only at the Cython level by using macros to translate between the unprefixed names in Cython and the prefixed names in libGAP.

I am not sure I understand. Currently in Cython on can do something like

    from sage.libs.gap.libgap import libgap
    g=libgap.ProjectiveGeneralLinearGroup(3,3)

How will this change under what you propose?

[jdemeyer]

Replying to dimpase:

    from sage.libs.gap.libgap import libgap
    g=libgap.ProjectiveGeneralLinearGroup(3,3)

How will this change under what you propose?

The Python interface won't change at all. I am talking about how sage.libs.gap calls libGAP.

[jdemeyer]

As far as I can tell, GAP 4.9 has not been released. Does anybody know how close we are to an actual release?

[slelievre]

I think GAP 4.9.0 is considered a public beta for GAP 4.9.

The list of releases at

• ​https://www.gap-system.org/Releases/

still displays GAP 4.8.10 as the latest release.

In the list of past releases there, the GAP 4.8, 4.7, 4.6, 4.5 series start at GAP 4.8.2, 4.7.2, 4.6.2, 4.5.4, so probably GAP 4.x.y with those x and lower y were considered beta.

Still, seeing how 4.9.0 works with Sage would be nice.

[jdemeyer]

Where is the GAP source tarball which is supposed to be used here?

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​72b5066	Unprefixed libGAP interface
​b7278a1	Upgrade to GAP 4.9

[dimpase]

Replying to jdemeyer:

Where is the GAP source tarball which is supposed to be used here?

here: ​https://www.gap-system.org/pub/gap/gap-4.9/beta/

[jdemeyer]

Replying to nthiery:

The branch attached to this ticket updates Sage to run on top of ​a branch of GAP by Markus Pfeiffer that adds libgap compilation and ​will be merged soon in the devel version of GAP.

It seems that this branch which "will be merged soon" is still not merged. It would be good to have an idea of whether or not that will happen.

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​d28b575	Unprefixed libGAP interface
​daf8754	Unprefixed libGAP interface
​40e644a	Upgrade to GAP 4.9

[nthiery]

According to ​https://github.com/gap-system/gap/pull/1205#issuecomment-385670578, Markus's libgap branch won't be merged in GAP 4.9: it's not yet ready enough. Bummer.

We are discussing with Sebastian and Thomas what we can do to move forward here. They are very interested as well by libgap for the integration between GAP and Julia.

Tentative steps:

• As a warm up, upgrade our current gap and libgap spkg to 4.8.10
• Upgrade our current gap and libgap spkg to 4.9; with the many changes to the build system, this may get more tricky
• To make the switch to GAP's libgap less urgent, investigate whether we could change our current libgap spkg to not prefix GAP symbols, in order to be able to use GAP's dynamic packages; see #25273
• On the GAP side: move toward more incremental changes. In particular, extract the changesets from Markus branch that are non controversial and ready, and get them merged in GAP (4.9? 4.10?)

[slelievre]

​GAP 4.9.1 was released in May 2018.

This is the first stable release of GAP 4.9 (GAP 4.9.0 was a beta for GAP 4.9).

[gh-antonio-rojas]

I'm confused - I just built GAP 4.9.1 from the upstream tarball and 'make install' *does* install /usr/lib/libgap.so and libgap's headers. Is this a different libgap than the one mentioned here to be included in 4.10?

[slelievre]

One comment at pull request 1205 in GAP's github repo said GAP won't ship libGAP before GAP 4.10:

• ​GAP discussion: no libgap before GAP 4.10

Maybe this was changed though.

[jdemeyer]

Has anybody asked GAP developers for a policy on the prefixing?

In Cernay, I proposed that GAP should prefix some/all of their names like T_INT -> GAP_T_INT. For compiling GAP (+ GAP packages) itself, we can use a file with defines like

#define  T_INT  GAP_T_INT

to ensure backwards compatibility. This way, in GAP itself, one could use either T_INT or GAP_T_INT. Outside of GAP, only GAP_T_INT would work.

I think this is relatively easy to implement (I'm willing to do it) but I don't know what upstream GAP thinks of it.

[slelievre]

​GAP 4.9.2 was released in July 2018.

[nthiery]

Hi,

For the record: I experimented a bit a month ago and a bit more this morning with Dima with the latest gap master that has make libgap and make install-libgap rules. See the following branch, which builds libgap from GAP's pristine sources:

​https://git.sagemath.org/sage.git/log/?h=u/nthiery/gap-libgap

Note that, at this stage, Sage won't start with it; maybe even not compile.

[nthiery]

Has anybody asked GAP developers for a policy on the prefixing?

In Cernay, I proposed that GAP should prefix some/all of their names like T_INT -> GAP_T_INT. For compiling GAP (+ GAP packages) itself, we can use a file with defines like

#define  T_INT  GAP_T_INT

to ensure backwards compatibility. This way, in GAP itself, one could use either T_INT or GAP_T_INT. Outside of GAP, only GAP_T_INT would work.

I think this is relatively easy to implement (I'm willing to do it) but I don't know what upstream GAP thinks of it.

That's the idea indeed. Eventually they will provide a standalone header file that will define the official GAP API, and where all symbols will be prefixed. To bootstrap the process, we (well mostly Max!) reviewed and annotated the symbols that are used in Sage:

​https://hackmd.io/emNi76svSWCh1fBeLKqPdA#

[gh-timokau]

Thank you for working on this! Sage using an up-to-date gap and doing away with the additional libgap package will simplify packaging.

[vdelecroix]

update milestone 8.3 -> 8.4

[slelievre]

GAP 4.9.3 was released.

• ​GAP 4.9.3 release announcement

[dimpase]

note that the prefix of the tarball should start with src/ - else one gets weird error messages from the python's tar.

GAPs make install target now works in a preliminary form - on Linux for sure.

[dimpase]

This is WIP - builds, but libgap.pyx interaction loop has to be rewritten using new API.

Also, sage --gap is broken

gap: hmm, I cannot find 'lib/init.g' maybe use option '-l <gaproot>'?

---

New commits:

​c766ad6	Merge branch 'u/jdemeyer/upgrade_to_gap_4_9' of trac.sagemath.org:sage into libgap
​5152637	building GAP and libGAP from GAP
​6bed83a	changes for using libGAP from GAP - part 1
​f069122	removing util*

[dimpase]

oops, one still needs initialize() from util.pyx, in some form...

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​8c28e13	Revert "removing util*"
​9c22e72	few comments

[nthiery]

Great to see the progress! Sounds like a productive week in Siegen. Thanks so much.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​14919d3

update util and the GAP package

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​b3dc304	Merge branch 'develop' into libgap
​8a8a146	use MarkBag instead of MARK_BAG
​c5a5d4f	no more *_BAG, and a call signature fix
​d13fc80	more compilation fixes
​8b5ccbe	removed debugging utils (they need a rewrite)

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​a0616de

adding --nointeract to libgap startup options

[dimpase]

at this point I am at

sage: libgap(1)
Error, Variable: '_rich_repr_' must have a value
Error, Variable: '_ipython_canary_method_should_not_exist_' must have a\
 value
[... several more errors like above]
gap: panic, could not open *errout*!

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​9cc327f

adding --nointeract to libgap startup options

[dimpase]

In the current branch I am able to run

sage: g=libgap.SymmetricGroup(4)
sage: print(g.Order())
24
sage: i=g.Order().sage()
sage: i
24

So it's outputting GAP object that is broken ATM.

I'll try fixing the "old" GAP interface, perhaps it will help.

[nthiery]

Replying to dimpase:

In the current branch I am able to run

sage: g=libgap.SymmetricGroup(4)
sage: print(g.Order())
24
sage: i=g.Order().sage()
sage: i
24

Nice! Making good progress!

So it's outputting GAP object that is broken ATM. I'll try fixing the "old" GAP interface, perhaps it will help.

I am not sure what's broken above?

[dimpase]

Replying to nthiery:

So it's outputting GAP object that is broken ATM. I'll try fixing the "old" GAP interface, perhaps it will help.

I am not sure what's broken above?

see comment:86 - displaying (lib)GAP objects is broken. Also,

sage: gap(1)
** Gap crashed or quit executing 'SetUserPreference("HistoryMaxLines", 30);' **
Restarting Gap and trying again
** Gap crashed or quit executing '\$sage1:=1;;' **
...

the latter is probably due to some scripts gotten messed up by the upgrade.

And error handling in libgap interface needs work, too.

[dimpase]

libgap's display problem seems to be ipython-specific. Indeed

$ ./sage --python
Python 2.7.15 (default, Sep 15 2018, 05:05:36) 
[GCC 8.2.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from sage.all import *
>>> libgap(1)
1

[dimpase]

Some discussions related to libgap API:

• ​https://github.com/gap-system/gap/issues/2864
• ​https://github.com/gap-system/gap/issues/2839

and an accepted PR to fix a bug that was breaking libgap/Sage interface:

​https://github.com/gap-system/gap/pull/2840

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​ece8cfc

fix gap() interface and gap_console, removed some old stuff

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​043fb95

fixing all but one doctests in interfaces/gap.py

[dimpase]

One error - tab completion does not work on GAP objects:

sage -t --long --warn-long 49.3 src/sage/interfaces/gap.py
**********************************************************************
File "src/sage/interfaces/gap.py", line 1628, in sage.interfaces.gap.GapElement._tab_completion
Failed example:
    'Centralizer' in s5._tab_completion()
Exception raised:
    Traceback (most recent call last):
      File "/mnt/opt/Sage/sage-dev/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 659, in _run
        self.compile_and_execute(example, compiler, test.globs)
      File "/mnt/opt/Sage/sage-dev/local/lib/python2.7/site-packages/sage/doctest/forker.py", line 1070, in compile_and_execute
        exec(compiled, globs)
      File "<doctest sage.interfaces.gap.GapElement._tab_completion[1]>", line 1, in <module>
        'Centralizer' in s5._tab_completion()
      File "sage/misc/cachefunc.pyx", line 2316, in sage.misc.cachefunc.CachedMethodCallerNoArgs.__call__ (build/cythonized/sage/misc/cachefunc.c:13467)
        self.cache = f(self._instance)
      File "/mnt/opt/Sage/sage-dev/local/lib/python2.7/site-packages/sage/interfaces/gap.py", line 1633, in _tab_completion
        v = P.eval(r'\$SAGE.OperationsAdmittingFirstArgument(%s)'%self.name())
      File "/mnt/opt/Sage/sage-dev/local/lib/python2.7/site-packages/sage/interfaces/gap.py", line 583, in eval
        result = Expect.eval(self, input_line, **kwds)
      File "/mnt/opt/Sage/sage-dev/local/lib/python2.7/site-packages/sage/interfaces/expect.py", line 1354, in eval
        for L in code.split('\n') if L != ''])
      File "/mnt/opt/Sage/sage-dev/local/lib/python2.7/site-packages/sage/interfaces/gap.py", line 789, in _eval_line
        raise RuntimeError(message)
    RuntimeError: Gap produced error output
    Error, no method found! For debugging hints type ?Recovery from NoMethodFound
    Error, no 1st choice method found for `Iterator' on 1 arguments

       executing \$SAGE.OperationsAdmittingFirstArgument(x);
**********************************************************************
1 item had failures:
   1 of   3 in sage.interfaces.gap.GapElement._tab_completion

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​0128112

few important Cython types fixed

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​c4d128e	pass the correct error callback function
​732cbdd	removing libgap_enter/exit

[dimpase]

in gap.* interface, tab completion is broken due to outdated code in src/ext/gap/sage.g: with GAP 4.10 one gets

gap> Read("sage.g");
gap> s5:=SymmetricGroup(5);
Sym( [ 1 .. 5 ] )
gap> \$SAGE.OperationsAdmittingFirstArgument(s5);
Error, no method found! For debugging hints type ?Recovery from NoMethodFound
Error, no 1st choice method found for `Iterator' on 1 arguments at /mnt/opt/Sage/sage-dev/local/gap/latest/lib/methsel2.g:250 called from
OPERATIONS[i + 1] at sage.g:69 called from
<function "LastReadValue">( <arguments> )
 called from read-eval loop at *stdin*:4
type 'quit;' to quit to outer loop

in GAP 4.8.6 this works:

gap> Read("sage.g");
gap> s5:=SymmetricGroup(5);
Sym( [ 1 .. 5 ] )
gap> \$SAGE.OperationsAdmittingFirstArgument(s5);
[ <Operation "ViewObj">, <Operation "ViewString">, <Operation "NameFunction">, <Operation "SetNameFunction">, 
...

I've asked ​here, as this is due to format change of internal GAP data...

[dimpase]

Very similar outdated code is in OperationInspector.operations in sage/libs/gap/operations.py.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​4121824

fix for tab completion for GAP interface

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​1d60fdd

fix tab completion in libgap interface

[dimpase]

broken error handling:

sage: a=libgap(1)
sage: getattr(a,'_rich_repr_',None)
Error, Variable: '_rich_repr_' must have a value
sage: 

(with a default argument, getattr should just return it, with raising anything)

[dimpase]

Please see ​https://github.com/gap-system/gap/issues/2874 for the current sticking point, which is error handling and processing of error messages. Basically, the question is whether it's possible to retain the behaviour of libGAP without patches to the GAP's kernel.

I'd like someone who knows more about libGAP error handling to have a look at badly butchered by me parts in the branch dealing with it, and suggest what should be done.

Another (easier) thing to fix is GAP and libgap documentation display.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​e352f7e

modest progress - can do libgap(1)

[dimpase]

the interaction with ipython (which tries to get things like _rich_repr_ from GAP to display GAP objects) is far from done. The current problem:

sage: a=libgap(41)
sage: a
41
sage: b=libgap(42)
---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
...
ValueError: libGAP: PrintTo: cannot open stream for output
Error, Length: <list> must be a list (not a boolean or fail)
...

this looks like a bug in my new (bad) implementation of GAP objects printing in Sage.

[dimpase]

perhaps we should rather try rebasing libGAP to GAP 4.10, which looks a less daunting task now than a total replacement with "native" GAP's libgap, get it working, and then replace all the libgap_* functions by the native ones.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​406cae6

still the interaction with ipython is broken

[dimpase]

On the present branch, I get

sage: a=libgap(1)
sage: a
*** trouble in PRINT_OR_APPEND_TO_STREAM***
...
*** trouble in PRINT_OR_APPEND_TO_STREAM***
1

after this GAP is pretty much nuked. This happens during ipython's attempts to pretty-print a, so that it tries to find _rich_repr_ etc. Specifically, at least on the system I am running this, the trouble starts not immediately, but where _rich_png_ (or the previous thing in the loop) is checked for by get_real_method in IPython/utils/dir2.py.

If I run the same from ./sage --python (after loading Sage there as usual) at least this much (and more) works.

I don't have a good idea how to debug this, so I'd like to pass the token now.

[dimpase]

oops, wrong ticket

[embray]

As long as we're upgrading GAP we should make sure DESTDIR builds work now; see #25044 which this conflicts with. But if this can get done soon we can skip #25044 and incorporate it into this. I'll give you a patch for it if you want.

I'm working on testing this on Cygwin now.

[embray]

Okay, I am again confused as to what upstream tarball to use, because the one in the ticket description no longer matches the checksum.

[dimpase]

I just checked that md5=017738e0ba9e166a19084d68123d3e1f as in GAP package checksum matches the md5 of ​https://github.com/dimpase/gap/releases/download/dev/gap-4.dev.tar.gz

Perhaps your download just got corrupted?

[thansen]

GAP 4.9.3 was uploaded to Debian unstable yesterday, the sagemath Debian package is broken until we can use GAP 4.9. Is the patch here already enough to use libgap from GAP 4.9 directly? It does not apply cleanly to sage 8.4. Or would you say updating the separate libgap to 4.9 is a better idea?

[dimpase]

Replying to thansen:

GAP 4.9.3 was uploaded to Debian unstable yesterday, the sagemath Debian package is broken until we can use GAP 4.9. Is the patch here already enough to use libgap from GAP 4.9 directly? It does not apply cleanly to sage 8.4.

the patch here is very far from a working one.

Or would you say updating the separate libgap to 4.9 is a better idea?

If you could manage this, it would be great and very useful, but it's a very nontrivial amount of work, due to substantial changes in GAP internals that happened in GAP 4.9.

[thansen]

I see. If there was progress on this from you guys it would be very much appreciated. The freeze period for the next Debian release starts in January. If we can't fix the problem in time, sage will not be in the next Debian release, which will be the stable release for two years.

[jdemeyer]

Replying to thansen:

The freeze period for the next Debian release starts in January.

For those of us who are not Debian experts, where is this documented? And what kind of changes are still allowed during the "freeze" period? For example, suppose for the sake of argument that this SageMath ticket is only merged in February, could it still be added as a patch to the Debian SageMath package?

[thansen]

It is documented here: ​https://release.debian.org/buster/freeze_policy.html

The broken sagemath will eventually be automatically removed from Debian testing, which will become the next Debian release. After February 12 it cannot migrate back to testing even if it is fixed. The earlier transition freeze on January 12 means that no more library updates with SONAME change can be done (which might be relevant for a sage update too).

[thansen]

About the example you mentioned: This ticket does not need to be merged, we just need a usable patch. It seems that the gap maintainer is open to providing libgap.la, see ​https://bugs.debian.org/912862 . It is not yet clear if gap 4.10 is released in time to be included before the freeze.

[embray]

This ticket mentions GAP 4.10, but should we not be focusing instead on GAP 4.9? Or would getting Sage working against GAP 4.10 imply support for 4.9 as well? I would want to check against both, and starting with the existing release (4.9) seems simpler...

Is there something at the system integration level I could be able to help with? ISTM this needs to be a high priority.

[embray]

Replying to thansen:

About the example you mentioned: This ticket does not need to be merged, we just need a usable patch. It seems that the gap maintainer is open to providing libgap.la, see ​https://bugs.debian.org/912862 . It is not yet clear if gap 4.10 is released in time to be included before the freeze.

If that's the case, for the sake of integration, it might make more sense to pin GAP in Debia to 4.9 and focus on getting a Sage out that works against GAP 4.9 instead of focusing on 4.10. Given the amount of time left to do this, waiting on an uncertain GAP 4.10 package(s) landing in Debian seems a bit risky...

[dimpase]

I think getting Sage's libGAP work with GAP 4.9 and/or 4.10 is much harder than in used to be in 4.8.x, due to major changes to GAP internals (although I have not tried it yet).

[nthiery]

Posting on behalf of Alexander Konovalov who does not yet have a trac account:

​http://www.gap-system.org/pub/gap/gap-4.10/

has now GAP 4.10.0. The website will be updated in due course, but that means that GAP 4.10 is out.

That's excellent news. Now it's up to Sage to catch up.

[embray]

Great! From what I saw yesterday it seemed like there were some doubts about how soon 4.10 would be released. But this being the case I rescind my previous comment.

[embray]

Replying to git:

Branch pushed to git repo; I updated commit sha1. New commits:

​406cae6

still the interaction with ipython is broken

If I'm to understand correctly, you just added this patch for debugging purposes, right? It's not intended to go into the final product is it? I'm going to look into this problem.

[dimpase]

Replying to embray:

Replying to git:

Branch pushed to git repo; I updated commit sha1. New commits:

​406cae6

still the interaction with ipython is broken

If I'm to understand correctly, you just added this patch for debugging purposes, right? It's not intended to go into the final product is it? I'm going to look into this problem.

That's right, it's for debugging purposes (although it merely shows that something is going wrong, not more :-)). You might like to coordinate this with Jeroen, as he's going to work on this branch too...

[embray]

I'm updating it right now to the 4.10 release. Jeroen is probably a better person to work on the LibGAP integration just because he has more experience with it. But if there any specific segfaults or anything I could look at I will. I'll take a look, for example, at the tab-completion issue...

[embray]

I'm also rebasing this branch on current develop, which needs a bit of work...

[dimpase]

Replying to nthiery:

Posting on behalf of Alexander Konovalov who does not yet have a trac account:

​http://www.gap-system.org/pub/gap/gap-4.10/

Alex should be aware that he can post on trac using his github account!

[embray]

Another thing that it seems still hasn't been done is to update the spkg-install for GAP to use DESTDIR-based installation. I'll just work on that simultaneously with this. If we have to upgrade GAP anyways that should be part of the process (and may expose some flaws in GAP's new installation process...)

[embray]

Needed to modify build/make/deps to directly make GAP a build dependency of sagelib as well, which is now needed (and remove the obsolete reference to the libgap spkg).

[jdemeyer]

Replying to embray:

I'm updating it right now to the 4.10 release.

Are you actually doing that? I haven't seen any update on the branch here.