When running gunzip /nonexistent/*gz, the error message from gunzip is very
misleading: gzip: /nonexistent/*gz.gz: No such file or directory
It's misleadng in two ways:
1. it refers to gzip, when I was running gunzip
Yes, gunzip merely calls "gzip -d", so the message is coming from from
gzip which does what it does regardless of who calls it.
2. it refers to a file specification that I did not provide, by naively
appending .gz to the file spec
Yes, that's what gzip -d does: if you say "gzip -d foo" it wants to
decompress foo.gz because "foo" doesn't end in ".gz". In your case the
file name was "/nonexistent/*gz" and since that doesn't end in ".gz" it
looked for "/nonexistent/*gz.gz" and didn't find it.
Doubtless you have bigger fish to fry.
Yes, that sounds right. Closing the bug report.