make sure email addresses used with 'tell' and 'killperson' exist in keyring

[joshrabinowitz]

This PR a fix for #176.

#176 is a bug with tell which adds all keys with a substring matching the specified username. For example, git secret tell bob will add all keys with the string bob anywhere in the username or email address.

Here's the details:

• each gpg key is associated with an email address, and optionally a name.
• gpg does substring matching against both the email address and the username when looking for keys matching a string.

Also,

• the nameassociated with a key is not guaranteed to be unique and
• the email can be a substring of other names or emails

For the above reasons, this PR changes the code so you have to specify users by email address with git secret tell. (Edit: The docs always said to use email addresses so there is no doc change.)

@sobolevn @simbo1905 thoughts/suggestions/input?

[joshrabinowitz]

This PR does still have a bug where if

• you are using keys where one's email address is a substring of another's (for example [email protected] and [email protected]),

then

• using git secret tell [email protected] will add keys for both users and not just the one you probably meant.

I don't see an easy way to fix that and figured we could tackle that in a separate PR.

If you see a good way to fix this issue, or have an other input on this PR, please let me know @sobolevn @simbo1905 @dave-pollock

[simbo1905]

LGTM. I left a minor comment.

[joshrabinowitz]

I think this is ready for merge @sobolevn !

[sobolevn]

🙌