[petsc-dev] Build error with zlib

[Adrian Croucher]

hi

I've just started having errors building PETSc on both my Github CI 
pipeline and on another machine, as a result of zlib failing to 
download. (I'm using the download-zlib option.) The error is:

UNABLE to CONFIGURE with GIVEN OPTIONS    (see configure.log for details):
Error during download/extract/detection of ZLIB:
Unable to download package ZLIB from: http://www.zlib.net/zlib-1.2.11.tar.gz

...

Unable to download package ZLIB from: 
http://ftp.mcs.anl.gov/pub/petsc/externalpackages/zlib-1.2.11.tar.gz

...

Unable to download package ZLIB from: 
ftp://ftp.mcs.anl.gov/pub/petsc/externalpackages/zlib-1.2.11.tar.gz

...

Unable to download package ZLIB from: 
https://www.mcs.anl.gov/petsc/mirror/externalpackages/zlib-1.2.11.tar.gz

When I test these URLs, the first one from www.zlib.net does indeed give 
a 404. But the other ones are valid. I assumed that it's trying these 
URLs in sequence until it finds one that works?

I am using an older version of PETSc (3.15.5) as there is a PETSc bug in 
more recent versions that affects my project and means I can't upgrade 
until it is resolved.

Regards, Adrian

-- 
Dr Adrian Croucher
Senior Research Fellow
Department of Engineering Science
University of Auckland, New Zealand
email: a.croucher at auckland.ac.nz
tel: +64 (0)9 923 4611