[PATCH 07/10] git-bisect.sh: don't use the -a or -o option with the test command

From: Elia Pinto <gitter.spiros@gmail.com>
Date: May 15, 2014, 14:21 UTC
Message-ID: <1400163710-28333-7-git-send-email-gitter.spiros@gmail.com>
In-Reply-To: <1400163710-28333-1-git-send-email-gitter.spiros@gmail.com>

Even though POSIX.1 lists -a/-o as options to "test", they are marked "Obsolescent XSI". Scripts using these expressions should be converted as follow:

test "$1" -a "$2"

should be written as:

test "$1" && test "$2"

Likewise

test "$1" -o "$2"

should be written as:

test "$1"  test "$2"

But note that, in test, -a has higher precedence than -o while "&&" and "||" have equal precedence in the shell.

The reason for this is that the precedence rules were never well specified, and this made many sane-looking uses of "test -a/-o" problematic.

For example, if $x is "=", these work according to POSIX (it's not portable, but in practice it's okay):

   $ test -z "$x"
   $ test -z "$x" && test a = b

but this doesn't

   $ test -z "$x" -a a = b
   bash: test: too many arguments

because it groups "test -n = -a" and is left with "a = b".

Similarly, if $x is "-f", these

   $ test "$x"
   $ test "$x" || test c = d

correctly adds an implicit "-n", but this fails:

   $ test "$x" -o c = d
   bash: test: too many arguments

Signed-off-by: Elia Pinto <gitter.spiros@gmail.com>
---
Inspired from this discussion http://permalink.gmane.org/gmane.comp.version-control.git/137056

 git-bisect.sh |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/git-bisect.sh b/git-bisect.sh
index af4d04c..1e0d602 100755
--- a/git-bisect.sh
+++ b/git-bisect.sh
@@ -408,7 +408,7 @@ bisect_replay () {
 	bisect_reset
 	while read git bisect command rev
 	do
-		test "$git $bisect" = "git bisect" -o "$git" = "git-bisect" || continue
+		test "$git $bisect" = "git bisect" || test "$git" = "git-bisect" || continue
 		if test "$git" = "git-bisect"
 		then
 			rev="$command"

-- 
1.7.10.4