Re: [RFC] Define "precious" attribute and support it in `git clean`

Thanks a lot, that makes perfect sense!

Thanks to Elijah we may also have discovered why the idea of precious files
didn't get implemented last time it came up: it's too much work to make
all portions of the code aware.

I don't know if this time will be different as I can only offer to implement
the syntax adjustment, whatever that might be (possibly after validating
the candidate against a corpus of repositories), along with the update
to `git clean` so it leaves precious files alone by default and a new flag
to also remove precious files.

Maybe that already is something worth having, but I can also imagine
that ideally there is a plan for retrofitting other portions of git as
well along with the resources to actually do it.

On 15 Oct 2023, at 18:31, Junio C Hamano wrote:

Sebastian Thiel [off-list ref] writes:

quoted

A particularly interesting question brought up here also was the question
of what's more important: untracked files, or precious files? Are they
effectively treated the same, or is there a difference?

Think of it this way.  There are two orthogonal axes.

 (1) Are you a candidate to be tracked, even though you are not
     tracked right now?

 (2) Should you be kept and make an operation fail that wants to
     remove you to make room?

For untracked files, both are "Yes".  As we already saw in the long
discussion, precious files are "not to be added and not to be
clobbered", so you'd answer "No" and "Yes" [*].

In other words, both are equally protected from getting cloberred.

    Side note: for completeness, for ignored files, the answers are
    "No", and "No".  The introduction of "precious" class makes a
    combination "No-Yes" that hasn't been possible so far.

Elijah, thanks for doing a very good job of creating a catalog of
kludges we accumulated over the years for the lack of proper support
for the precious paths.  I think they should be kept for backward
compatibility, but for new users they should not have to learn any
of them once we have the support for precious paths.