FR: don't sign commits without a description

[jalil-salame]

If you are interested in this feature please look at #5108 (comment). Tl; dr: not likely to be accepted, instead help out with #4747

Is your feature request related to a problem? Please describe.

I have to use a hw key to sign my commits at work, this means I have to set sign-all = true until we have the jj sign command.

Setting sign-all = true causes way too many commits to be signed. Signing only commits with a description would be better.

For example a typical jj commit workflow causes three commits to be signed:

1. sign the snapshot of the working copy
2. sign the commit you have described
3. sign the new commit that was created

Describe the solution you'd like
Only sign commits with a commit message, this would prevent signatures 1 and 3 in the above example.

Describe alternatives you've considered
Once jj sign is completed, set sign-all = false and do one of:

• jj sign main..bookmark before pushing to sign all commits in a branch
• signing.sign-on-push = true do jj sign main..bookmark before pushing automatically.

Additional context
This is specially painful when using a HW key as you need to enter a PIN and touch the HW key for the signature to be processed.

I would prefer to only sign before pushing as if I mistype the PIN I might loose the commit message. I haven't so far though c:

[mrnossiom]

I have taken the habit to have all my commit signed on GitHub. My GPG key is cached for some time, so this is not a blocker for me. Though it is sometimes annoying that running common jj commands, which trigger a repo snapshot, force me to enter my password to continue (as it needs to sign the snapshot commit).

[jalil-salame]

For me, I have a hardware key which requires me to reach around and touch it to sign the commits, it is in an inconvenient place rn, but I can't cache that so it is extra annoying.

[martinvonz]

I think the alternatives options you mention sound better. So if anyone wants to make progress in this area, I would prefer they do it by helping get #4747 landed.

[bnjmnt4n]

Closing this for the more general solution #4712 (and accompanying PR #4747).