Re: Problem: staging of an alternative repository

[Pasha Bolokhov <pasha.bolokhov@gmail.com>]

    Hi,

I've looked more attentively, here are my observations and the
resulting suggestions:

- Suggest only to check *string-wise* the given "path" against
$GIT_DIR. Both or one of them may be relative paths (but comparison
best be performed when converted to absolute paths). That's the only
solution which will give predictable results, but does not handle
symlinks: if you have symlinks (so that both differing paths actually
point to the same location) the comparison will return failure. Only
if you have an exact string-wise match do we ignore the "path"

- With this way of comparison, only the root ".git_new" will be
ignored. Submodules will likely contain the usual ".git". Since the
code normally ignores ".git" anyway, and I do not intend to change
that, I don't see how submodule detection can be affected

- The problem of resolving symlinks is in a very general case
insolvable (e.g. imagine one of the symlinks points to another
filesystem which may be up or down depending on the day of week - it's
easy to plot a scenario where symlinks will resolve (or even fail to
resolve) differently at different runs)

- Even if it was solvable, the current implementation of handling
".git" certainly does not check any symlinks:
        $  mv -i   .git   .metadata
        $  ln -s .metadata .git
  Then certainly "git add -A" will grab all ".metadata" and store into itself

  Please let me know what you think. Again, I can try to carefully do
this suggestion

Pavel


On Thu, May 1, 2014 at 11:20 PM, Duy Nguyen <pclouds@gmail.com> wrote:
> On Thu, May 1, 2014 at 4:35 AM, Jonathan Nieder <jrnieder@gmail.com> wrote:
>>>     Now I know, the '--git-dir' option may usually be meant to use
>>> when the repository is somewhere outside of the work tree, and such a
>>> problem would not arise. And even if it is inside, sure enough, you
>>> can add this '.git_new' to the ignores or excludes. But is this really
>>> what you expect?
>>
>> I think it's more that it never came up.  Excluding the current
>> $GIT_DIR from what "git add" can add (on top of the current rule of
>> excluding all instances of ".git") seems like a sensible change,
>> assuming it can be done without hurting the code too much. ;-)
>
> I think it came up before. Changes could be very messy (but I did not
> check carefully) because right now we just compare $(basename $path)
> with ".git", one path component, simple and easy. Checking against
> $GIT_DIR means all path components. You also have to deal with
> relative and absolute paths and symlinks in some path components. You
> may also need to think if submodule detection code (checking ".git"
> again) is impacted. On top of that, read_directory() code is already
> messy (or at least scary to me) with all kinds of shortcuts we have
> added over the years. A simpler solution may be ignoring all
> directories whose last component is  "$GIT_DIR_NAME" (e.g.
> GIT_DIR_NAME=.git_new).
> --
> Duy