Re: [PATCH] Avoid warning when bisecting a merge

[Junio C Hamano <gitster@pobox.com>]

Christian Couder <chriscool@tuxfamily.org> writes:

> Le jeudi 4 septembre 2008, Gustaf Hendeby a écrit :
>> Trying to compare an empty string as a number results in an error,
>> hence make sure checkout_done is set before using it.
>
> This patch seems to work fine. 
>
>> Signed-off-by: Gustaf Hendeby <hendeby@isy.liu.se>
>
> Acked-by: Christian Couder <chriscool@tuxfamily.org>

Have you actually read the patch and thought about it before acking it?

Why does a variable that says "have we done checkout?" have three states?
Certainly it is not like "yes, no, dunno", right?  checkout_done=0 which
was added by Gustaf, checkout_done=1 is the state the test checks with
(presumably set by check_good_are_ancestors_of_bad), and checkout_done=''
which the code does before returning?

>> diff --git a/git-bisect.sh b/git-bisect.sh
>> index 69a9a56..05d14b3 100755
>> --- a/git-bisect.sh
>> +++ b/git-bisect.sh
>> @@ -437,6 +437,7 @@ bisect_next() {
>>  		"refs/bisect/skip-*" | tr '\012' ' ') &&
>>
>>  	# Maybe some merge bases must be tested first
>> +	checkout_done=0
>>  	check_good_are_ancestors_of_bad "$bad" "$good" "$skip" || exit
>>  	test "$checkout_done" -eq "1" && checkout_done='' && return

> PS: After thinking about it, I wonder if we should remove $checkout_done 
> entirely and use the return value from "check_merge_bases" 
> and "check_good_are_ancestors_of_bad" to know if a checkout was done.

Yup, that might make more sense. In the meantime, I suspect this makes
more sense than introducing a new state "0".

diff --git c/git-bisect.sh w/git-bisect.sh
index 69a9a56..73f01bb 100755
--- c/git-bisect.sh
+++ w/git-bisect.sh
@@ -30,6 +30,7 @@ OPTIONS_SPEC=
 . git-sh-setup
 require_work_tree
 
+checkout_done=
 _x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
 _x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
 
@@ -418,7 +419,7 @@ check_good_are_ancestors_of_bad() {
 	_side=$(git rev-list $_good ^$_bad)
 	if test -n "$_side"; then
 		check_merge_bases "$_bad" "$_good" "$_skip" || return
-		test "$checkout_done" -eq "1" && return
+		test -n "$checkout_done" && return
 	fi
 
 	: > "$GIT_DIR/BISECT_ANCESTORS_OK"
@@ -438,7 +439,7 @@ bisect_next() {
 
 	# Maybe some merge bases must be tested first
 	check_good_are_ancestors_of_bad "$bad" "$good" "$skip" || exit
-	test "$checkout_done" -eq "1" && checkout_done='' && return
+	test -n "$checkout_done" && checkout_done='' && return
 
 	# Get bisection information
 	BISECT_OPT=''