]> Pileus Git - ~andy/git/commitdiff
checkout: Don't crash when switching away from an invalid branch.
authorAlexandre Julliard <julliard@winehq.org>
Sat, 8 Nov 2008 12:03:59 +0000 (13:03 +0100)
committerJunio C Hamano <gitster@pobox.com>
Sun, 9 Nov 2008 18:11:39 +0000 (10:11 -0800)
When using alternates, it is possible for HEAD to end up pointing to
an invalid commit. git checkout should be able to recover from that
situation without crashing.

Signed-off-by: Alexandre Julliard <julliard@winehq.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
builtin-checkout.c
t/t2011-checkout-invalid-head.sh [new file with mode: 0755]

index 1deda927cdfcbcdcb751aca3338ac77ef0aad836..05eee4ecc71d7a20d9faf59c849d3c693ae4cc8d 100644 (file)
@@ -32,7 +32,7 @@ static int post_checkout_hook(struct commit *old, struct commit *new,
 
        memset(&proc, 0, sizeof(proc));
        argv[0] = name;
-       argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
+       argv[1] = xstrdup(sha1_to_hex(old ? old->object.sha1 : null_sha1));
        argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
        argv[3] = changed ? "1" : "0";
        argv[4] = NULL;
@@ -360,10 +360,10 @@ static void update_refs_for_switch(struct checkout_opts *opts,
 
        strbuf_init(&msg, 0);
        old_desc = old->name;
-       if (!old_desc)
+       if (!old_desc && old->commit)
                old_desc = sha1_to_hex(old->commit->object.sha1);
        strbuf_addf(&msg, "checkout: moving from %s to %s",
-                   old_desc, new->name);
+                   old_desc ? old_desc : "(invalid)", new->name);
 
        if (new->path) {
                create_symref("HEAD", new->path, msg.buf);
@@ -419,7 +419,7 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
         * a new commit, we want to mention the old commit once more
         * to remind the user that it might be lost.
         */
-       if (!opts->quiet && !old.path && new->commit != old.commit)
+       if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
                describe_detached_head("Previous HEAD position was", old.commit);
 
        if (!old.commit) {
diff --git a/t/t2011-checkout-invalid-head.sh b/t/t2011-checkout-invalid-head.sh
new file mode 100755 (executable)
index 0000000..764bb0a
--- /dev/null
@@ -0,0 +1,18 @@
+#!/bin/sh
+
+test_description='checkout switching away from an invalid branch'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+       echo hello >world &&
+       git add world &&
+       git commit -m initial
+'
+
+test_expect_success 'checkout master from invalid HEAD' '
+       echo 0000000000000000000000000000000000000000 >.git/HEAD &&
+       git checkout master --
+'
+
+test_done