At the end of configure, show installation hints for non-enabled optional packages separately

[mjo]

When running the configure script, --enable-foo and --disable-foo should be used to control the installation of optional packages.

Original wishlist item:

With respect to the system-package support, this means that ./configure should not try to find any optional packages that I don't want, and it shouldn't tell me to install them. For example,

$ ./configure
...
Checking whether SageMath should install SPKG gp2c...
checking installing pari? ... no
checking for gp2c... no
configure: using pari/gp from the system, but building gp2c
configure: one might prefer to install a system-wide gp2c, instead
configure: and re-run configure.
configure: gp prefix is /usr 
configure: pari.cfg is /usr/share/pari/pari.cfg 
configure: no suitable system package found for SPKG gp2c
using Sage's gp2c SPKG
...
gp2c-0.0.10.p0:                              no suitable system package; optional, use "./configure --enable-gp2c" to install
...
configure: Hint: The following SPKGs did not find equivalent system packages:
configure:   cbc gp2c libsemigroups
checking for the package system in use... gentoo
configure: Hint: Installing the following system packages is recommended and may avoid building some of the above SPKGs from source:
configure:   $ # install the following packages: sci-mathematics/gp2c

I guess this is partly due to the default of if_installed for --enable-foo (which I think is a bad default, but that's another matter), but the same thing happens if I explicitly pass --disable-gp2c.

In this ticket, as a milder change, we show the list of system packages corresponding to non-enabled optional packages separately.

To test this branch, remember to use ./bootstrap before ./configure.

Critical for Sage 9.3 because there is evidence that users get concerned when too many packages are suggested to be installed.

Related:

• #29498: Do not check for system packages of disabled optional packages

[mkoeppe]

To clarify, they are not "enabled". But the hints certainly make no distinction between enabled and non-enabled packages.

This ticket overlaps with #29363 - "At the end of configure, indicate which optional/experimental packages are configured to be installed". Help on this is very welcome!

[mkoeppe]

I guess this is partly due to the default of if_installed for --enable-foo (which I think is a bad default, but that's another matter)

Yes, the fact that an existing installation in SAGE_LOCAL influences configure's defaults is, of course, a quirk of Sage. We should not change this because it has a long tradition; but it would be good to have an additional configure option to disable it and obtain more standard configure behavior.

[mjo]

I think it's reasonable to use an existing spkg if one exists, and I guess that's why if_installed was chosen as the default. But someone doing sage -i foo and someone just happening to have foo installed on the system express two very different intentions. This will become more apparent as we support more and more optional packages via spkg-configure, and they're all enabled by default.

[mkoeppe]

No, if_installed means "if installed as an SPKG in SAGE_LOCAL."

[mkoeppe]

"Enabling" an optional package really just means to make sure it is installed as an spkg if the system does not provide it already.

[mjo]

Replying to mkoeppe:

No, if_installed means "if installed as an SPKG in SAGE_LOCAL."

Oh, OK. That's less crazy to me, then. But in that case, ./configure definitely should not be looking for those system packages and telling me to install them (since I've told it to use those packages only if they're installed as SPKGs).

[mkoeppe]

Replying to mjo:

But in that case, ./configure definitely should not be looking for those system packages and telling me to install them (since I've told it to use those packages only if they're installed as SPKGs).

Yes, I agree that the hint should not be issued for disabled optional packages. Would you like to work on this improvement?

Testing for the system packages, on the other hand, is a bit trickier because they might be dependencies of an enabled optional package.

[mkoeppe]

Setting new milestone based on a cursory review of ticket status, priority, and last modification date.

[mkoeppe]

New commits:

​50b1b25

m4/sage_spkg_collect.m4: Show installation hints for non-enabled optional packages separately

[mkoeppe]

Thanks!

[mkoeppe]

Setting priority to blocker to bring this ticket to the attention of the release bot.

[vbraun]

Not a blocker

[mkoeppe]

Could you please clarify whether you mean that you do not plan to merge this ticket before the 9.4 series?