Sage hangs for a long time while building

[Michel VAN DEN BERGH]

In order to possibly investigate the bug https://groups.google.com/g/sage-support/c/jyO88vE2gys I thought I might build Sage myself.

This worked fine (very nice build system!). However if I type "make" again, even without any changes, it takes more than five minutes before Sage is rebuilt. 

I am just wondering if this is normal... Here is where the hang is.

Running command Preparing editable metadata (pyproject.toml)
[sagelib-10.9.beta5] [spkg-install]   + meson setup --reconfigure /home/vdbergh/sage-github/sage /home/vdbergh/sage-github/sage/build/sage-distro -Dbuildtype=release -Db_ndebug=if-release -Db_vscrt=md --default-library=static --native-file=/home/vdbergh/sage-github/sage/build/pkgs/../platform/meson/sage-configure-native-file.ini -DSAGE_LOCAL=/home/vdbergh/sage-github/sage/local -Dbuild-docs=True --native-file=/home/vdbergh/sage-github/sage/build/sage-distro/meson-python-native-file.ini

[Dima Pasechnik]

On Sat, Feb 7, 2026 at 11:09 AM 'Michel VAN DEN BERGH' via
sage-support <sage-s...@googlegroups.com> wrote:
>
> In order to possibly investigate the bug https://groups.google.com/g/sage-support/c/jyO88vE2gys I thought I might build Sage myself.
>
> This worked fine (very nice build system!). However if I type "make" again, even without any changes, it takes more than five minutes before Sage is rebuilt.
>
> I am just wondering if this is normal... Here is where the hang is.

this is normal, as, for the time being, "make" triggers re-scanning of
the documentation directory by Meson (the building backend), which
isn't fast (that's 15 years of technical debt sitting there, Sage's
documenation building system is rather non-standard now).

If you did "./configure --disable-doc" (not to build documentation in
html/pdf), then "make" will be much faster, as the latter bottleneck
is then avoided.

>
> Running command Preparing editable metadata (pyproject.toml)
> [sagelib-10.9.beta5] [spkg-install] + meson setup --reconfigure /home/vdbergh/sage-github/sage /home/vdbergh/sage-github/sage/build/sage-distro -Dbuildtype=release -Db_ndebug=if-release -Db_vscrt=md --default-library=static --native-file=/home/vdbergh/sage-github/sage/build/pkgs/../platform/meson/sage-configure-native-file.ini -DSAGE_LOCAL=/home/vdbergh/sage-github/sage/local -Dbuild-docs=True --native-file=/home/vdbergh/sage-github/sage/build/sage-distro/meson-python-native-file.ini
>

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[Michel VAN DEN BERGH]

On Saturday, February 7, 2026 at 6:55:43 PM UTC+1 wrote:

On Sat, Feb 7, 2026 at 11:09 AM 'Michel VAN DEN BERGH' via
sage-support  wrote:
>
> In order to possibly investigate the bug https://groups.google.com/g/sage-support/c/jyO88vE2gys I thought I might build Sage myself.
>
> This worked fine (very nice build system!). However if I type "make" again, even without any changes, it takes more than five minutes before Sage is rebuilt.
>
> I am just wondering if this is normal... Here is where the hang is.

this is normal, as, for the time being, "make" triggers re-scanning of
the documentation directory by Meson (the building backend), which
isn't fast (that's 15 years of technical debt sitting there, Sage's
documenation building system is rather non-standard now).

If you did "./configure --disable-doc" (not to build documentation in
html/pdf), then "make" will be much faster, as the latter bottleneck
is then avoided.

Thanks a lot! I did that and it worked!

Best,

Michel 

>
> Running command Preparing editable metadata (pyproject.toml)
> [sagelib-10.9.beta5] [spkg-install] + meson setup --reconfigure /home/vdbergh/sage-github/sage /home/vdbergh/sage-github/sage/build/sage-distro -Dbuildtype=release -Db_ndebug=if-release -Db_vscrt=md --default-library=static --native-file=/home/vdbergh/sage-github/sage/build/pkgs/../platform/meson/sage-configure-native-file.ini -DSAGE_LOCAL=/home/vdbergh/sage-github/sage/local -Dbuild-docs=True --native-file=/home/vdbergh/sage-github/sage/build/sage-distro/meson-python-native-file.ini
>
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> To unsubscribe from this group and stop receiving emails from it, send an email to .

[Michel VAN DEN BERGH]

I had another surprise. I create a new GIT branch to do some debugging. Afterwards I switched back to master and did make.

To my surprise this started a completely new build of Sage. Is this normal?

Best,

Michel

[Michel VAN DEN BERGH]

I guess the answer is here

https://doc.sagemath.org/html/en/developer/git_advanced.html#minimize-the-recompilation-time

[Michel VAN DEN BERGH]

Ok I understand my mistake. If you freshly compile Sage you are not in master but in develop...