Re: [PATCH] Add test that checkout does not overwrite entries in .git/info/exclude

> Nguyen Thai Ngoc Duy <pclouds@gmail.com> writes:
>
>> On Mon, Nov 21, 2011 at 10:18 PM, Junio C Hamano <gitster@pobox.com> wrote:
>>> In the medium term, I think one reasonable way forward solving the "TODO
>>> that used to be tracked but now untracked and ignored" issue is to
>>> introduce "info/exclude-override" that comes between command line and
>>> in-tree patterns. The info/exclude file is designed as the fallback
>>> definition to be used when all other sources are too lax, and comes near
>>> the precedence stack; the "TODO" situation however calls for an override
>>> that is stronger than the in-tree patterns.
>>
>> "info/precious" might be a better name
>
> The above is only about the precedence order and is not about introducing
> the new "precious" class at all.

>>> In the longer term, we should carefully determine if we need "precious" in
>>> the first place. The last time this was brought up there were people who
>>> argued they are OK with having to remove the ignored file by hand when
>>> checking out another branch (i.e. we switch the semantics of "ignored" so
>>> that they are "not tracked but all precious").
>>>
>>> I think it matters in two cases.
>>>
>>>  (1) If you change an untracked "cruft" file on branch A into a directory
>>>     with tracked files in it on another branch B. If you are on branch A,
>>>     have that "cruft" file (perhaps it is a build product after running
>>>     "make"), and try to checkout branch B, such an updated "git checkout"
>>>     will start erroring out telling you that "cruft" will be lost.
>>>
>>>  (2) If you have a directory on branch A, underneath of which there are
>>>     untracked "cruft" files (e.g. think "build/" directory that is full
>>>     of "*.o" files and ".gitignore" to mark object files as ignored but
>>>     is otherwise empty), and another branch B that has the same path as a
>>>     file. If you are on branch A, have "cruft" files in that directory,
>>>     and try to checkout branch B, such an updated "git checkout" will
>>>     start erroring out telling you that "cruft" will be lost.
>>
>> I think we should do this regardless precious being added or not.
>
> Because (see below)?

>
> "clean -x" is more subtle. It has been a way to say "Remove cruft the
> usual way, and in addition, remove the expendable build products, just
> like 'make clean' _should_ do, but I do not trust my Makefile". If we
> introduced "precious", it would be very clear what it should do---even
> with "-x" precious files should be kept. But if we don't and just try to
> get away by changing the semantics of "ignored", they will still need to
> be removed, so we won't really get the "precious".
>
> The conclusion from this is that it is a mistake to change the semantics
> of "ignored" from the current "untracked and expendable if needed" if the
> purpose of that change is to avoid introducing the new "precious" class.
>
> I don't care too much about it, as I do not use "git clean -x" myself ;-)
> but that wouldn't stop others from think about the issue and try to come
> up with a good solid design.