bisect: error out when passing bad path parameters

As reported by Mark Lodato, "git bisect", when it was started with
path parameters that match no commit was kind of working without
taking account of path parameters and was reporting something like:

Bisecting: -1 revisions left to test after this (roughly 0 steps)

It is more correct and safer to just error out in this case, before
displaying the revisions left, so this patch does just that.

Note that this bug is very old, it exists at least since v1.5.5.
And it is possible to detect that case earlier in the bisect
algorithm, but it is not clear that it would be an improvement to
error out earlier, on the contrary it may change the behavior of
"git rev-list --bisect-all" for example, which is currently correct.

Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/bisect.c b/bisect.c
index dc18db8af96b093d7cb16eb88d3f738f98dc30f6..88881f7b6ed7a69498561912dbf4934697c17e4b 100644 (file)
--- a/bisect.c
+++ b/bisect.c
@@ -986,6 +986,12 @@ int bisect_next_all(const char *prefix)
                exit(1);
        }
 
+       if (!all) {
+               fprintf(stderr, "No testable commit found.\n"
+                       "Maybe you started with bad path parameters?\n");
+               exit(4);
+       }
+
        bisect_rev = revs.commits->item->object.sha1;
        memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), 41);
 

diff --git a/t/t6030-bisect-porcelain.sh b/t/t6030-bisect-porcelain.sh
index def397c53a76dead449710eaca6333c2e1fb36aa..dc9e8d030a6e803ac5a022e4f0685016879edaf0 100755 (executable)
--- a/t/t6030-bisect-porcelain.sh
+++ b/t/t6030-bisect-porcelain.sh
@@ -567,6 +567,11 @@ test_expect_success 'skipping away from skipped commit' '
        test "$para3" = "$PARA_HASH3"
 '
 
+test_expect_success 'erroring out when using bad path parameters' '
+       test_must_fail git bisect start $PARA_HASH7 $HASH1 -- foobar 2> error.txt &&
+       grep "bad path parameters" error.txt
+'
+
 #
 #
 test_done