Please support system spdlog and fmt (and newer fmt), or allow disabling this functionality

[gspr]

Hello,

I don't know whether the Github or the Gitlab repository is canonical, and I couldn't find your email address, so I just made a guess to file an issue here.

Now that Hera is a dependency of GUDHI, I need to package Hera for Debian in order to upgrade the GUDHI Debian package to 3.2.x. I'm having some issues preparing a Hera Debian package because of the bundled copies of the spdlog and fmt libraries. Debian abhors and disallows bundled copies of libraries. I am therefore faced with needing to strip out these from Hera, and change the Hera code to allow the use of system-wide spdlog/fmt. While I will probably manage do this, the change is quite invasive and would incur a future divergence between the Debian package and the official upstream Hera. This becomes maintenance debt for the future.

I would therefore ask you if you could please consider making it possible for (through macros or CMake magic) Hera to use of system-wide spdlog and fmt libraries. In the case of fmt, it also seems that the bundled copy is quite ancient (version 4 series?), while the fmt library is now at an incompatible version 6 series upstream.

Alternatively, if it's easier, it would help a lot if there could be an option to simply disable the use of spdlog/fmt altogether. (I'm maybe missing something, but I'm a bit confused about the role of mandatory logging in Hera in the first place…)

Thank you for considering this.

[anigmetov]

Hello, I'll take a look at it (I hope very soon); for now I think the easiest option is the last thing you suggested, disabling the logging by default. I have no idea about the gitlab repo; for me, the two canonical repos are this one and the bitbucket repo https://bitbucket.org/grey_narn/hera/src/master/

Arnur Nigmetov

[gspr]

grey-narn notifications@github.com writes:

Hello, I'll take a look at it (I hope very soon); for now I think the easiest option is the last thing you suggested, disabling the logging by default.

Great, thanks!

Could you elaborate a bit about whether I could just rip out all logging in general? Is there a reason I'm missing for mandatory logging within Hera?

I have no idea about the gitlab repo; for me, the two canonical repos are this one and the bitbucket repo https://bitbucket.org/grey_narn/hera/src/master/

Sorry, that was a brainfart on my part, I meant Bitbucket when I said Gitlab :-)

[anigmetov]

From what I see now, all logging can be removed completely. I think it is present only in the matching distance calculation, and is useless to anyone but me. Moreover, if I am not mistaken, GUDHI does not use the matching distance at all, they are interested in Wasserstein and bottleneck only, so the easiest thing is to eliminate the whole matching directory.

[gspr]

grey-narn notifications@github.com writes:

From what I see now, all logging can be removed completely.

Thanks for the info! Maybe you could preprocessor-protect all the logging in the future?

I think it is present only in the matching distance calculation,

Hmm, doesn't look like it:

$ grep -ir spdlog wasserstein/ | wc -l
523

Did I misunderstand something?

[gspr]

Oh by the way, and this is a bit off-topic, but just so I don't make any wild assumptions: is the fmt library used only for formatting logs, or also in writing/reading persistence diagrams?

[anigmetov]

I removed spdlog and fmt from Hera entirely, getting rid of lots of debug code.

[gspr]

grey-narn notifications@github.com writes:

I removed spdlog and fmt from Hera entirely, getting rid of lots of debug code.

Sounds great – thanks!