show-branch: -g and --current are incompatible

When "--current" is given to "git show-branch" running in the
"--reflog" mode, the code tries to reference a "reflog" message
that does not even exist.  This is because the --current is not
prepared to work in that mode.

The reason "--current" exists is to support this request:

    I list branches on the command line.  These are the branchesI
    care about and I use as anchoring points. I may or may not be on
    one of these main branches.  Please make sure I can view the
    commits on the current branch with respect to what is in these
    other branches.

And to serve that request, the code checks if the current branch is
among the ones listed on the command line, and adds it only if it is
not to the end of one array, which essentially lists the objects.
The reflog mode additionally uses another array to list reflog
messages, which the "--current" code does not add to.  This leaves
one uninitialized slot at the end of the array of reflog messages,
and causes the program to show garbage or segfault.

Catch the unsupported (and meaningless) combination and exit with a
usage error.

There are other combinations of options that are incompatible but
have not been tested.  Add test to cover them while adding coverage
for this new combination.

Reported-by: Gregory David <gregory.david@p1sec.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index e12c5e80e3e4425831b9803c334245eaedf3bd9a..73e8edbf023ef41c9cc2d40bd35bddbdca61cda4 100644 (file)
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -711,6 +711,10 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
                                "--all/--remotes/--independent/--merge-base");
        }
 
+       if (with_current_branch && reflog)
+               die(_("options '%s' and '%s' cannot be used together"),
+                   "--reflog", "--current");
+
        /* If nothing is specified, show all branches by default */
        if (ac <= topics && all_heads + all_remotes == 0)
                all_heads = 1;

diff --git a/t/t3202-show-branch.sh b/t/t3202-show-branch.sh
index 7a1be73ce8771b851dfc2c7a95d80dece4c2b5cb..f2b9199007752eded932a8da541e1a86e350d10a 100755 (executable)
--- a/t/t3202-show-branch.sh
+++ b/t/t3202-show-branch.sh
@@ -161,4 +161,18 @@ test_expect_success 'show branch --reflog=2' '
        test_cmp actual expect
 '
 
+# incompatible options
+while read combo
+do
+       test_expect_success "show-branch $combo (should fail)" '
+               test_must_fail git show-branch $combo 2>error &&
+               grep -e "cannot be used together" -e "usage:" error
+       '
+done <<\EOF
+--all --reflog
+--merge-base --reflog
+--list --merge-base
+--reflog --current
+EOF
+
 test_done