geo: WKT writing not working with GEOS bundled with CockroachDB

[timgraham]

Describe the problem

Django's WKTWriter.write() doesn't work with the GEOS library bundled with CockroachDB.

To Reproduce

> from django.contrib.gis.geos import GEOSGeometry, WKTWriter
> wkt_w = WKTWriter()
> ref = GEOSGeometry('POINT (5 23)')
> wkt_w.write(ref).decode())
POINT ( )

Expected behavior

Ouput of: POINT (5.0000000000000000 23.0000000000000000).

The expected behavior happens with GEOS 3.8.1 compiled from source but not with the GEOS 3.8.1 included with CockroachDB.

Additional information

Here's Django's interface to GEOSWKTWriter_write.

If no one has any idea what the cause may be, I can investigate further. I'm not intimately familiar with how this all works.

Environment:

• CockroachDB version 20.2 beta 2

Jira issue: CRDB-3710

[blathers-crl]

Hello, I am Blathers. I am here to help you get the issue triaged.

Hoot - a bug! Though bugs are the bane of my existence, rest assured the wretched thing will get the best of care here.

I have CC'd a few people who may be able to assist you:

• @rafiss (found keywords: Django)
• @cockroachdb/bulk-io (found keywords: import)

If we have not gotten back to your issue within a few business days, you can try the following:

• Join our community slack channel and ask on #cockroachdb.
• Try find someone from here if you know they worked closely on the area and CC them.

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[otan]

the WKT unit tests work, so I'm not sure how this came about.

[timgraham]

Could you point to how libgeos.so and libgeos_c.so are generated? Maybe inspecting that would reveal something. I've been looking more closely at the Python side but I haven't come across anything suspicious.

Incidentally, is it possible to make it so that patchelf --set-rpath '/usr/local/lib/cockroach/' /usr/local/lib/cockroach/libgeos_c.so isn't required? Also sudo ln -s /usr/local/lib/cockroach/libgeos.so /usr/local/lib/cockroach/libgeos.so.3.8.1? (For anyone else reading, we discussed these things at #54429 (comment).)

[otan]

Could you point to how libgeos.so and libgeos_c.so are generated? Maybe inspecting that would reveal something. I've been looking more closely at the Python side but I haven't come across anything suspicious.

https://github.com/cockroachdb/cockroach/blob/master/Makefile#L798

You can try fudge with this if you are willing -- ./build/builder.sh mkrelease linux will build the binary and libs will be in lib.docker_amd64/

Incidentally, is it possible to make it so that patchelf --set-rpath '/usr/local/lib/cockroach/' /usr/local/lib/cockroach/libgeos_c.so isn't required? Also sudo ln -s /usr/local/lib/cockroach/libgeos.so /usr/local/lib/cockroach/libgeos.so.3.8.1? (For anyone else reading, we discussed these things at #54429 (comment).)

I took a look at this and it was quite complicated with our build setup, and we're revamping that in the upcoming release anyway (the issue in particular is that cmake and specifying rpath does not work when cross compiling).

Note we already special case mac because of this, but the patchelf tool was not available in the builder.

[otan]

does

+       patchelf --set-rpath '/usr/local/lib/cockroach/' lib/libgeos_c.so
+       patchelf --set-soname libgeos.so lib/libgeos.so
+       patchelf --replace-needed libgeos.so.3.8.1 libgeos.so lib/libgeos_c.so

avoid the need for the symlink?
note that this patchelf isn't required if you dlopen libgeos_c.so before libgeos_c.so.

[timgraham]

Yes. I ran those commands from /usr/local/lib/cockroach/ and libgeos_c.so is in that directory so I omitted lib/.

[timgraham]

I ruled out issues with the Cockroach GEOS fork by compiling it from source. All Django tests pass with that libgeos_c.so.

Perhaps it's best to wait and see if the revamp to the build process that you mentioned happens to fix this issue.

[timgraham]

I confirmed Django works without creating a symlink and modifying the libgeos files in Cockroach 21.1 beta 1. The strange WKT writing issues described here still remain.

[timgraham]

This started working in v22.1 alpha 4. libgeos_c.so and libgeos.so there are different than those in the alpha 3.