[PATCH v2] mergetool: use more conservative temporary filenames

[David Aguilar <davvid@gmail.com>]

Avoid filenames with multiple dots so that overly-picky tools do
not misinterpret their extension.

Previously, foo/bar.ext in the worktree would result in e.g.

	./foo/bar.ext.BASE.1234.ext

This can be improved by having only a single .ext and using
underscore instead of dot so that the extension cannot be
misinterpreted.  The resulting path becomes:

	./foo/bar_BASE_1234.ext

Suggested-by: Sergio Ferrero <sferrero@ensoftcorp.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: David Aguilar <davvid@gmail.com>
---
Changes since v1

The commit message changed to say "./foo" instead of "foo".

The patch now uses Junio's suggestion to minimize variables,
and preserves the original leading ./ just in case there are
tools that rely on having ./ in front of relative paths.

 git-mergetool.sh | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/git-mergetool.sh b/git-mergetool.sh
index 9a046b7..96a61ba 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -228,11 +228,17 @@ merge_file () {
 		return 1
 	fi
 
-	ext="$$$(expr "$MERGED" : '.*\(\.[^/]*\)$')"
-	BACKUP="./$MERGED.BACKUP.$ext"
-	LOCAL="./$MERGED.LOCAL.$ext"
-	REMOTE="./$MERGED.REMOTE.$ext"
-	BASE="./$MERGED.BASE.$ext"
+	if BASE=$(expr "$MERGED" : '\(.*\)\.[^/]*$')
+	then
+		ext=$(expr "$MERGED" : '.*\(\.[^/]*\)$')
+	else
+		BASE=$MERGED
+		ext=
+	fi
+	BACKUP="./${BASE}_BACKUP_$$$ext"
+	LOCAL="./${BASE}_LOCAL_$$$ext"
+	REMOTE="./${BASE}_REMOTE_$$$ext"
+	BASE="./${BASE}_BASE_$$$ext"
 
 	base_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==1) print $1;}')
 	local_mode=$(git ls-files -u -- "$MERGED" | awk '{if ($3==2) print $1;}')
-- 
2.1.2.375.gd89e6a9