stash show: fix segfault with --{include,only}-untracked

When `git stash show --include-untracked` or
`git stash show --only-untracked` is run on a stash that doesn't include
an untracked entry, a segfault occurs. This happens because we do not
check whether the untracked entry is actually present and just attempt
to blindly dereference it.

Ensure that the untracked entry is present before actually attempting to
dereference it.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/stash.c b/builtin/stash.c
index 8922a1240c6344f7086b0eccb08e6c7b2dddef30..82e4829d447a4fff506cb3fd3fc86597a0833bdf 100644 (file)
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -900,10 +900,14 @@ static int show_stash(int argc, const char **argv, const char *prefix)
                diff_tree_oid(&info.b_commit, &info.w_commit, "", &rev.diffopt);
                break;
        case UNTRACKED_ONLY:
-               diff_root_tree_oid(&info.u_tree, "", &rev.diffopt);
+               if (info.has_u)
+                       diff_root_tree_oid(&info.u_tree, "", &rev.diffopt);
                break;
        case UNTRACKED_INCLUDE:
-               diff_include_untracked(&info, &rev.diffopt);
+               if (info.has_u)
+                       diff_include_untracked(&info, &rev.diffopt);
+               else
+                       diff_tree_oid(&info.b_commit, &info.w_commit, "", &rev.diffopt);
                break;
        }
        log_tree_diff_flush(&rev);

diff --git a/t/t3905-stash-include-untracked.sh b/t/t3905-stash-include-untracked.sh
index 2e6796725bd60e2519ce33dae722be02fb5e2c9c..1c9765928d0f72b0ae05d12b2477d1731dad29bc 100755 (executable)
--- a/t/t3905-stash-include-untracked.sh
+++ b/t/t3905-stash-include-untracked.sh
@@ -405,4 +405,19 @@ test_expect_success 'stash show --include-untracked errors on duplicate files' '
        test_i18ngrep "worktree and untracked commit have duplicate entries: tracked" err
 '
 
+test_expect_success 'stash show --{include,only}-untracked on stashes without untracked entries' '
+       git reset --hard &&
+       git clean -xf &&
+       >tracked &&
+       git add tracked &&
+       git stash &&
+
+       git stash show >expect &&
+       git stash show --include-untracked >actual &&
+       test_cmp expect actual &&
+
+       git stash show --only-untracked >actual &&
+       test_must_be_empty actual
+'
+
 test_done