[Debian-pan-maintainers] Bug#1141635: fastparquet: AttributeError on import - module 'cramjam' has no attribute 'gzip'

[Rebecca N. Palmer]

Package: python3-fastparquet
Version: 2026.5.0-1
Severity: grave
Justification: renders package unusable

I am currently upgrading pandas, and as part of this, attempted to test 
its parquet I/O functionality.  This failed to even import fastparquet, 
with the error

AttributeError: module 'cramjam' has no attribute 'gzip'.  Did you mean: 
'bzip2'?

e.g. https://salsa.debian.org/science-team/pandas/-/jobs/9907658

(fastparquet's own autopkgtest does not actually test anything, because 
plain pybuild-autopkgtest cannot find the tests.  This is probably a bug 
in itself.)

I do not know whether this bug is actually in fastparquet or in cramjam; 
it is not *obviously* known to either upstream.