[libfido2] Coverage builds are failing

[LDVG]

Hi,

Our coverage builds have been failing since 22 April 2025 with error messages similar to

...
Starting Step #5
Step #5: Already have image (with digest): gcr.io/oss-fuzz-base/base-runner
Step #5: [/corpus/fuzz_assert.zip]
Step #5:   End-of-central-directory signature not found.  Either this file is not
Step #5:   a zipfile, or it constitutes one disk of a multi-part archive.  In the
Step #5:   latter case the central directory and zipfile comment will be found on
Step #5:   the last disk(s) of this archive.
Step #5: unzip:  cannot find zipfile directory in one of /corpus/fuzz_assert.zip or
Step #5:         /corpus/fuzz_assert.zip.zip, and cannot find /corpus/fuzz_assert.zip.ZIP, period.
Step #5: Failed to unpack the corpus for fuzz_assert. This usually means that corpus backup for a particular fuzz target does not exist. If a fuzz target was added in the last 24 hours, please wait one more day. Otherwise, something is wrong with the fuzz target or the infrastructure, and corpus pruning task does not finish successfully.
...

I cannot reproduce this locally using the included infra/helper.py script. Any ideas as to what may be causing this?

Thanks in advance!

[martelletto]

It looks like this has happened a number of times but never root-caused:

• https://issues.oss-fuzz.com/issues/42477543
• https://issues.oss-fuzz.com/issues/42474801
• https://issues.oss-fuzz.com/issues/42471624
• https://issues.oss-fuzz.com/issues/391974929
• fuzztest coverage fails? #8997

[yawkat]

I have a similar issue with the micronaut project. I looked in the GCP buckets, and while the micronaut-corpus bucket has the corpora for all the fuzz targets, the zip files in micronaut-backup are incomplete. I believe that's where the coverage build is trying to download data from. Not sure what job is responsible for building the -backup, but I guess that's what's failing.