1 patch for repository http://darcs.net/screened:

patch d6f6944fabc17a460527e5a6309b608fcc1ca65b
Author: Ben Franksen <ben.franksen@online.de>
Date:   Mon Nov  8 17:08:39 CET 2021
  * catch all takeLock exceptions in withLockCanFail

  Note that withLockCanFail is used in commands that are otherwise read-only,
  such as annotate and log (with a filename), in order to create a patch
  index. These commands should not fail if taking the lock fails for whatever
  reason (e.g. no write permission). This is important for instance when using
  darcsweb.

Attachments

• catch-all-takelock-exceptions-in-withlockcanfail.dpatch
• patch-preview.txt

Looks fine.

I wonder if we should pass the exception message upwards so that the
caller can choose to print out a warning? I guess it's debatable
whether read-only commands should print out warnings about the index.

A warning would indicate to the user that we cannot create a patch index 
and why. Now, creating a patch index is quite expensive (we must read all 
patches in the history), so it is mostly an investment to improve the 
performance of /future/ commands of a similar nature. Explaining all of 
this would be quite verbose and probably confusing to inexperienced users.