[PATCH] Makefile: Fix CDPATH problem

[Jonathan Nieder <jrnieder@gmail.com>]

CDPATH takes scripts to unexpected places.  For example, with a CDPATH
including a blt directory:

 make -C templates DESTDIR='' install
 make[1]: Entering directory `/users/e477610/exptool/src/git-1.7.0.2/templates'
 install -d -m 755 '/home/e477610/exptool/share/git-core/templates'
 (cd blt && gtar cf - .) | \
	(cd '/home/e477610/exptool/share/git-core/templates' && umask 022 && gtar xof -)
 gtar: This does not look like a tar archive

The CDPATH mechanism does not implicitly add "." at the beginning of
CDPATH, which is the most irritating part.

Most git scripts already protect against use of CDPATH through
git-sh-setup, but the Makefile doesn’t.

Reported-by: Michael Cox <mhcox@bluezoosoftware.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
I wouldn’t have guessed that.  Thanks, Junio.

Michael Cox wrote:
> That fixed the build problem.  Thank you!

Here’s a patch to prevent it from happening again.

 Makefile |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/Makefile b/Makefile
index 4387d42..c1f4161 100644
--- a/Makefile
+++ b/Makefile
@@ -317,6 +317,12 @@ SCRIPT_PYTHON =
 SCRIPT_SH =
 TEST_PROGRAMS =
 
+# Having this variable in your environment would break scripts because
+# you would cause "cd" to be taken to unexpected places.  If you
+# like CDPATH, define it for your interactive shell sessions without
+# exporting it.
+unexport CDPATH
+
 SCRIPT_SH += git-am.sh
 SCRIPT_SH += git-bisect.sh
 SCRIPT_SH += git-difftool--helper.sh
-- 
1.7.0.2.468.g1637