Re: [PATCH v5 08/11] dir: simplify untracked cache "ident" field

On 2016-01-15 07.59, Christian Couder wrote:

It is not a good idea to compare kernel versions and disable
the untracked cache if it changes as people may upgrade and
still want the untracked cache to work. So let's just
compare work tree locations and kernel name to decide if we
should disable it.

Also it's not useful to store many locations in the ident
field and compare to any of them. It can even be dangerous
if GIT_WORK_TREE is used with different values. So let's
just store one location, the location of the current work
tree.

If this location changed and we still want an untracked
cache, let's delete the cache and recreate it.

Note that if an untracked cache has been created by a
previous Git version, then the kernel version is stored in
the ident field. As we now compare with just the kernel
name the comparison will fail and the untracked cache will
be disabled until it's recreated.

Signed-off-by: Christian Couder <redacted>
Helped-by: Torsten Bögershausen [off-list ref]

This could be my version of a commit message:

It is not a good idea to compare kernel versions and disable
the untracked cache if it changes as people may upgrade and
still want the untracked cache to work.

Drop the major and minor version from uname stored in ident.

It can be dangerous if GIT_WORK_TREE is used with different values.

So let's simplify the handling and store just store one line,
the uname of the system the location of the current work tree.

If this location changed and we still want an untracked
cache, let's delete the cache and recreate it.

The untracked cache can only be used by one type of OS, exporting a git repo
to different clients via a network to e.g. Linux and Windows means that
only one can use the untracked cache.

Note that if an untracked cache has been created by a
previous Git version, then the kernel version is stored in
the ident field. As we now compare with just the kernel
name the comparison will fail and the untracked cache will
be disabled until it's recreated.