Keep src/ clean by using --build-base when building sagelib

[mkoeppe]

Currently, building sagelib creates the src/build directory, with subdirectories cython_debug, cythonized, lib.UNAME, temp.UNAME.

In preparation for VPATH builds of sage-the-distribution (#21469), let's keep src/ clean by using setup.py --build-base=$SAGE_BUILD_DIR/sagelib

($SAGE_BUILD_DIR defaults to $SAGE_ROOT/var/tmp/sage/build/)

As a second goal of this ticket, setup.sh is put in charge of ALL sagelib building.

Some possibly useful information:

• Documentation on distutils (​https://docs.python.org/2/install/), describing use of --build-base to do VPATH builds.
• pip install keeps the source directory clean, building instead in a temporary directory, by copying the sources. pip install also offers options --build to select a build directory, but there are some pip issues: ​2060, ​2053, ​804 that affect this
• #14807 has some tricks to making VPATH builds work without copying all python source files. But it uses automake instead of setup.sh; we will not do this in our ticket.

[fbissey]

Am interesting issue is that technically cython_debug has to be installed somewhere (preferably somewhere standard) to be accessible at runtime separately from the source.

I do something in sage-on-gentoo but that's not really satisfactory.

[leif]

Replying to mkoeppe:

In preparation for VPATH builds of sage-the-distribution (#21469), let's keep src/ clean by using setup.py --build-base=$SAGE_ROOT/var/tmp/sage/build/sagelib

Please use --build-base=$SAGE_BUILD_DIR/sagelib.

[leif]

... and sagelib perhaps with a version suffix.

[mkoeppe]

Replying to leif:

Replying to mkoeppe:

In preparation for VPATH builds of sage-the-distribution (#21469), let's keep src/ clean by using setup.py --build-base=$SAGE_ROOT/var/tmp/sage/build/sagelib

Please use --build-base=$SAGE_BUILD_DIR/sagelib.

Yes, the plan *after* #21469 is to use the Sage builddir -- not just for sagelib, but also for other packages.

*Before* #21469 is merged, I want to use $SAGE_ROOT/var/tmp/sage/build/sagelib to match what other packages do.

[mkoeppe]

Ah, I see what you meant, now I've found $SAGE_BUILD_DIR. Changed description accordingly.

[leif]

Replying to mkoeppe:

Replying to leif:

Replying to mkoeppe:

In preparation for VPATH builds of sage-the-distribution (#21469), let's keep src/ clean by using setup.py --build-base=$SAGE_ROOT/var/tmp/sage/build/sagelib

Please use --build-base=$SAGE_BUILD_DIR/sagelib.

Yes, the plan *after* #21469 is to use the Sage builddir -- not just for sagelib, but also for other packages.

??? SAGE_BUILD_DIR exists since years already... (Its default is $SAGE_ROOT/var/tmp/sage/build/.)

*Before* #21469 is merged, I want to use $SAGE_ROOT/var/tmp/sage/build/sagelib to match what other packages do.

[mkoeppe]

Replying to leif:

??? SAGE_BUILD_DIR exists since years already... (Its default is $SAGE_ROOT/var/tmp/sage/build/.)

Yes, thanks, see my other comment.

[leif]

Ah ok, race condition.

[mkoeppe]

By the way, help with implementing this change would be appreciated. I haven't looked at the sagelib build system at all so far.

[mkoeppe]

New commits:

​e399bf4

First, wishful step

[jdemeyer]

Really sagelib-$SAGE_VERSION? Do you want to fill up everybody's hard disks with Sage build directories? Not to mention that this would require to rebuild everything whenever the Sage version changes.

[mkoeppe]

Fine with me without $SAGE_VERSION; I was just following leif's suggestion in comment 3.

[felixs]

i understand that SAGE_BUILD_DIR is the srcdir for toplevel configure.

as long as sagelib is rooted in $(toplevel)/src, it might be less confusing to choose $SAGE_BUILD_DIR/src (not $SAGE_BUILD_DIR/sagelib) as the builddir for sagelib.

(future: replace src by sagelib, but on both ends)

i dont know exactly how the approach using setup.py will emulate VPATH builds. i think it should imitate "what automake would do", where applicable.

[mkoeppe]

Replying to felixs:

i understand that SAGE_BUILD_DIR is the srcdir for toplevel configure.

No, it's $SAGE_ROOT/var/tmp/sage/build/

[felixs]

ok, nevermind (i meant to write "SAGE_BUILD_DIR is the *builddir* for toplevel"). that does not seem to be the case either.

still i am wondering why "src" does not (simply) translate to "src". (sure, i am slightly autotools biased).

[git]

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

​f3f275e	Put .cython_version next to cythonized files
​94a58f1	Make SAGE_BUILD_DIR variable available in sage-env, not just in sage-spkg
​a73fa06	Use SAGE_BUILD_DIR

[mkoeppe]

Here's a first version for review. It seems to work for me.

There are still some to-do items (see comments in src/Makefile):

• I am now using --build-base, but setup.sh also depends on SAGE_CYTHONIZED, defined in src/sage/env.py.

I think it would be better if setup.sh instead inferred that location from the build-base that was passed to it.

However, setup.sh already does a lot of stuff depending on SAGE_CYTHONIZED before distutils.core.setup is even called. Can this be fixed?

I think I could use some help from the Python experts in the cc list of this ticket on this.

• sage/libs/pari/auto_gen.pxi and sage/ext/interpreters/__init__.py still need to be taken care of in preparation for the VPATH build.

[jdemeyer]

Thinking about it more, I disagree with building in $SAGE_BUILD_DIR/sagelib by default.

$SAGE_LOCAL (which contains $SAGE_BUILD_DIR) is meant as install directory, not as build directory.

Let's keep $SAGE_LOCAL to be exactly the install directory and nothing else (*).

I do agree with making the build directory configurable for VPATH builds. For typical packages however, if you do not do a VPATH build, the build directory is the same as the source directory. Sage should follow the same model. This means that the build directory should be $SAGE_SRC by default.

(*) One could argue that $SAGE_BUILD_DIR is currently used as build directory for packages. That is true, but they are only used temporarily, they are not meant to actually store stuff. So this isn't so bad.

[felixs]

Let's keep $SAGE_LOCAL to be exactly the install directory and nothing else (*).

this is part of the problem with the current "build system". SAGE_LOCAL is *not* the install directory. it is where stuff ends up during the build process.

outside sage, an install directory is typically what you pass to --prefix, and where stuff is put into by "make install". you do that (if you are a sysadmin), after assuring that "make check" passes...

yes i know why SAGE_LOCAL exists, but it should be clear that it's not necessary and that it only has "evolved" that way. having simplified things in the past, now it is falling on your feet.

note how i tried to fix/work\ around that in my attempt to autotoolize sage (both the library and the distribution)... my point: the best approach will be to *not use SAGE_LOCAL* at all. here's the chance to cleanup sagelib, as a start.

that said: keep up the good and interesting work @mkoeppe. i hope i will have some more time later this year ...

[jdemeyer]

Replying to felixs:

this is part of the problem with the current "build system". SAGE_LOCAL is *not* the install directory.

Why do you think that $SAGE_LOCAL is not the install directory? It is the directory where everything is installed, which by definition makes it the install directory. The fact that Sage does not (yet) support --prefix doesn't change this fact.

the best approach will be to *not use SAGE_LOCAL* at all.

I like to know why you think that.

that said: keep up the good and interesting work @mkoeppe. i hope i will have some more time later this year ...

To be clear: I didn't say that this branch needs to be thrown out. I am just saying: keep the build directory configurable but keep the default what it currently is.

[felixs]

Why do you think that $SAGE_LOCAL is not the install directory?

you wrote it. "--prefix" is not implemented/supported. (but it should be). there's no way to really "install" stuff in the usual sense. e.g., there is no way to *install stuff after make check has passed*. (i don't know if toplevel make check is currently implemented at all, just a thought).

where everything is installed, which by definition makes it the install directory

actually nothing gets installed. what is done is mostly overhead. working around the fact that some packages don't work right after the build alone. when i was done with the "package content lists" for spkg-install, i noticed that it was a huge waste of time... don't repeat that, better just skip the "install" step.

I like to know why you think that [SAGE_LOCAL should not be used].

every instance/use of SAGE_LOCAL breaks sagelib on (lets call it) foreign distros a bit. that's not helpful. it will as well interfere with any attempt on rewriting sage-the-distribution (be it autotools based, or pip or ebuild). the autotools approach (not a necessary step, but an example) provides a transition path to anything...

sage-the-distribution is a platform for sage (core) development. no more, no less. other platforms will come and go. what is needed is sagelib without the dependency on this (and on SAGE_LOCAL). why: because developers should be able to use sagelib and develop sage extensions on *their own platforms*, with *their own* tools and *their own* review policies.

so: please embrace contributions that reduce the use of SAGE_LOCAL.

(yes, its getting off-topic. but i hope, this answers the question.)

[mkoeppe]

Replying to jdemeyer:

Thinking about it more, I disagree with building in $SAGE_BUILD_DIR/sagelib by default.

$SAGE_LOCAL (which contains $SAGE_BUILD_DIR) is meant as install directory, not as build directory.

Let's keep $SAGE_LOCAL to be exactly the install directory and nothing else (*).

I agree with you; see #21479.

[mkoeppe]

Replying to felixs:

outside sage, an install directory is typically what you pass to --prefix, and where stuff is put into by "make install". you do that (if you are a sysadmin), after assuring that "make check" passes...

See #21479 for a discussion of --prefix and make vs. make install.

But let's keep the discussion of the present ticket focused on the task at hand.

[mkoeppe]

Replying to jdemeyer:

I do agree with making the build directory configurable for VPATH builds. For typical packages however, if you do not do a VPATH build, the build directory is the same as the source directory. Sage should follow the same model. This means that the build directory should be $SAGE_SRC by default.

I agree on this as well. #21469 (VPATH for distro) will do that.

In this ticket, I first want to make the --build-base work. In particular, get rid of SAGE_CYTHONIZED.

This also works towards the eventual goal of making 'sagelib' pip-installable.

The actual location used is a detail that will be easy to change later.

(*) One could argue that $SAGE_BUILD_DIR is currently used as build directory for packages. That is true, but they are only used temporarily, they are not meant to actually store stuff. So this isn't so bad.

Yes, the current patch follows this practice. But this is temporary until #21469 is done.

[jdemeyer]

Replying to felixs:

Why do you think that $SAGE_LOCAL is not the install directory?

you wrote it. "--prefix" is not implemented/supported.

The fact that the installation process does not implement ./configure --prefix does not mean that it's not an installation process...

every instance/use of SAGE_LOCAL breaks sagelib

But why?

Of course, it's all a matter of definition. I consider the process of copying files to $SAGE_LOCAL an "installation" and you do not (for reasons which are still unclear to me). I think things will become much simpler for you if you accept the fact that $SAGE_LOCAL is the installation directory and that copying files to $SAGE_LOCAL is an installation.

but i hope, this answers the question

I absolutely does not. You are just saying "it breaks stuff" but not explaining why.

[dimpase]

Replying to jdemeyer:

Replying to felixs:

[...]

but i hope, this answers the question

I absolutely does not. You are just saying "it breaks stuff" but not explaining why.

One reason why is that in many deployment scenarios you will want to test what you have built before installing it. And Sage does not support this.

[felixs]

indeed. in "build"-"check"-"install" there is not much room for definitions of "build" and "install".

this is drifting towards the question of whether or not sage should stick to common practices and terminology. you know i think it should.

apologies for being off-topic again, this may be more related to #15105 -- there is no ticket for just "practices and terminology".

[jdemeyer]

Replying to dimpase:

One reason why is that in many deployment scenarios you will want to test what you have built before installing it. And Sage does not support this.

How does this relate to the existence of $SAGE_LOCAL?

[git]

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

​a854831

Put setup.sh in charge of all sagelib building

[jdemeyer]

Replying to felixs:

this is drifting towards the question of whether or not sage should stick to common practices and terminology. you know i think it should.

If those "common" practices and terminology make sense, of course it should.

Anyway, I am completely not following what you are trying to say. I feel that you are always wandering around my questions instead of answering them.

[mkoeppe]

I have created #21495 as a place for such discussions.