Spurious permission error during fetch phase while chain building

[Vincent Habchi]

Folks,

For a few months, I’ve been stumbling on a recurring permission error during chain building. Here is an example: 

--->  Fetching archive for p5.42-version
--->  Archive not available for p5.42-version, building locally
--->  Fetching distfiles for p5.42-version
Error: Failed to fetch version-0.9934.tar.gz: Failed to open file /Volumes/Development/optlocal/var/macports/distfiles/perl5/version-0.9934.tar.gz.TMP for writing: Permission denied
Error: Failed to fetch p5.42-version: Failed to fetch distfiles

It’s transient: if I relaunch the same build command, the process resumes without error… until either it terminates or hiccoughs on another such error. It’s not blocking, but it’s a pain because I can’t leave long builds unattended.

Has anyone else already experienced this? I apologise if it has somehow already been reported. It seems to happen on a variety of machines: the MacBook Pro M1 and MacMini M2 I use at work, as well as my new M5 MacBook Air, so it’s probably not a Flash quirk. 

Any idea?
Thanks,
Vincent