read-cache: optionally disallow NTFS .git variants

The point of disallowing ".git" in the index is that we
would never want to accidentally overwrite files in the
repository directory. But this means we need to respect the
filesystem's idea of when two paths are equal. The prior
commit added a helper to make such a comparison for NTFS
and FAT32; let's use it in verify_path().

We make this check optional for two reasons:

  1. It restricts the set of allowable filenames, which is
     unnecessary for people who are not on NTFS nor FAT32.
     In practice this probably doesn't matter, though, as
     the restricted names are rather obscure and almost
     certainly would never come up in practice.

  2. It has a minor performance penalty for every path we
     insert into the index.

This patch ties the check to the core.protectNTFS config
option. Though this is expected to be most useful on Windows,
we allow it to be set everywhere, as NTFS may be mounted on
other platforms. The variable does default to on for Windows,
though.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 0677bd8df..097fdd47e 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -239,6 +239,12 @@ core.protectHFS::
 	be considered equivalent to `.git` on an HFS+ filesystem.
 	Defaults to `true` on Mac OS, and `false` elsewhere.
 
+core.protectNTFS::
+	If set to true, do not allow checkout of paths that would
+	cause problems with the NTFS filesystem, e.g. conflict with
+	8.3 "short" names.
+	Defaults to `true` on Windows, and `false` elsewhere.
+
 core.trustctime::
 	If false, the ctime differences between the index and the
 	working tree are ignored; useful when the inode change time