@matheusbsbs / matheus-bagliano / commits / c990a4c11d

checkout: fix bug with --to and relative HEAD

Given "git checkout --to <path> HEAD~1", the new worktree's HEAD should begin life at the current branch's HEAD~1, however, it actually ends up at HEAD~2. This happens because: 1. git-checkout resolves HEAD~1 2. to satisfy is_git_directory(), prepare_linked_worktree() creates a HEAD for the new worktree with the value of the resolved HEAD~1 3. git-checkout re-invokes itself with the same arguments within the new worktree to populate the worktree 4. the sub git-checkout resolves HEAD~1 relative to its own HEAD, which is the resolved HEAD~1 from the original invocation, resulting unexpectedly and incorrectly in HEAD~2 (relative to the original) Fix this by unconditionally assigning the current worktree's HEAD as the value of the new worktree's HEAD. As a side-effect, this change also eliminates a dependence within prepare_linked_checkout() upon 'struct branch_info'. The plan is to eventually relocate "git checkout --to" functionality to "git worktree add", and worktree.c won't have knowledge of 'struct branch_info', so removal of this dependency is a step toward that goal. Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Eric Sunshine committed Jul 6, 2015 at 13:30 UTC c990a4c11dd7bb671da1b30e14568ad986621488

2 files changed +22 -4

builtin/checkout.c

+12 -4

@@ -863,6 +863,7 @@ static int prepare_linked_checkout(const struct checkout_opts *opts,

863 struct stat st;

864 struct child_process cp;

865 int counter = 0, len, ret;

866 + unsigned char rev[20];

867

868 if (!new->commit)

869 die(_("no branch specified"));

@@ -920,13 +921,20 @@ static int prepare_linked_checkout(const struct checkout_opts *opts,

921 real_path(get_git_common_dir()), name);

922 /*

923 * This is to keep resolve_ref() happy. We need a valid HEAD

923 - * or is_git_directory() will reject the directory. Any valid

924 - * value would do because this value will be ignored and

925 - * replaced at the next (real) checkout.

924 + * or is_git_directory() will reject the directory. Moreover, HEAD

925 + * in the new worktree must resolve to the same value as HEAD in

926 + * the current tree since the command invoked to populate the new

927 + * worktree will be handed the branch/ref specified by the user.

928 + * For instance, if the user asks for the new worktree to be based

929 + * at HEAD~5, then the resolved HEAD~5 in the new worktree must

930 + * match the resolved HEAD~5 in the current tree in order to match

931 + * the user's expectation.

932 */

933 + if (!resolve_ref_unsafe("HEAD", 0, rev, NULL))

934 + die(_("unable to resolve HEAD"));

935 strbuf_reset(&sb);

936 strbuf_addf(&sb, "%s/HEAD", sb_repo.buf);

929 - write_file(sb.buf, 1, "%s\n", sha1_to_hex(new->commit->object.sha1));

937 + write_file(sb.buf, 1, "%s\n", sha1_to_hex(rev));

938 strbuf_reset(&sb);

939 strbuf_addf(&sb, "%s/commondir", sb_repo.buf);

940 write_file(sb.buf, 1, "../..\n");

t/t2025-checkout-to.sh

+10

@@ -134,4 +134,14 @@ test_expect_success 'checkout with grafts' '

134 test_cmp expected actual

135 '

136

137 +test_expect_success 'checkout --to from relative HEAD' '

138 + test_commit a &&

139 + test_commit b &&

140 + test_commit c &&

141 + git rev-parse HEAD~1 >expected &&

142 + git checkout --to relhead HEAD~1 &&

143 + git -C relhead rev-parse HEAD >actual &&

144 + test_cmp expected actual

145 +'

146 +

147 test_done