@matheusbsbs / matheus-bagliano / commits / ebddf39396

sequencer: allow introducing new root commits

In the context of the new --rebase-merges mode, which was designed specifically to allow for changing the existing branch topology liberally, a user may want to extract commits into a completely fresh branch that starts with a newly-created root commit. This is now possible by inserting the command `reset [new root]` before `pick`ing the commit that wants to become a root commit. Example: reset [new root] pick 012345 a commit that is about to become a root commit pick 234567 this commit will have the previous one as parent This does not conflict with other uses of the `reset` command because `[new root]` is not (part of) a valid ref name: both the opening bracket as well as the space are illegal in ref names. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Johannes Schindelin committed May 4, 2018 at 01:01 UTC ebddf393964120628f60f6f5e435cde87cc209c6
2 files changed +62 -12
sequencer.c
+28 -12
@@ -2747,18 +2747,34 @@ static int do_reset(const char *name, int len, struct replay_opts *opts)
2747 if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
2748 return -1;
2749
2750 - /* Determine the length of the label */
2751 - for (i = 0; i < len; i++)
2752 - if (isspace(name[i]))
2753 - len = i;
2754 -
2755 - strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
2756 - if (get_oid(ref_name.buf, &oid) &&
2757 - get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
2758 - error(_("could not read '%s'"), ref_name.buf);
2759 - rollback_lock_file(&lock);
2760 - strbuf_release(&ref_name);
2761 - return -1;
2750 + if (len == 10 && !strncmp("[new root]", name, len)) {
2751 + if (!opts->have_squash_onto) {
2752 + const char *hex;
2753 + if (commit_tree("", 0, the_hash_algo->empty_tree,
2754 + NULL, &opts->squash_onto,
2755 + NULL, NULL))
2756 + return error(_("writing fake root commit"));
2757 + opts->have_squash_onto = 1;
2758 + hex = oid_to_hex(&opts->squash_onto);
2759 + if (write_message(hex, strlen(hex),
2760 + rebase_path_squash_onto(), 0))
2761 + return error(_("writing squash-onto"));
2762 + }
2763 + oidcpy(&oid, &opts->squash_onto);
2764 + } else {
2765 + /* Determine the length of the label */
2766 + for (i = 0; i < len; i++)
2767 + if (isspace(name[i]))
2768 + len = i;
2769 +
2770 + strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
2771 + if (get_oid(ref_name.buf, &oid) &&
2772 + get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
2773 + error(_("could not read '%s'"), ref_name.buf);
2774 + rollback_lock_file(&lock);
2775 + strbuf_release(&ref_name);
2776 + return -1;
2777 + }
2778 }
2779
2780 memset(&unpack_tree_opts, 0, sizeof(unpack_tree_opts));
t/t3430-rebase-merges.sh
+34
@@ -241,4 +241,38 @@ test_expect_success 'refuse to merge ancestors of HEAD' '
241 test_cmp_rev HEAD $before
242 '
243
244 +test_expect_success 'root commits' '
245 + git checkout --orphan unrelated &&
246 + (GIT_AUTHOR_NAME="Parsnip" GIT_AUTHOR_EMAIL="root@example.com" \
247 + test_commit second-root) &&
248 + test_commit third-root &&
249 + cat >script-from-scratch <<-\EOF &&
250 + pick third-root
251 + label first-branch
252 + reset [new root]
253 + pick second-root
254 + merge first-branch # Merge the 3rd root
255 + EOF
256 + test_config sequence.editor \""$PWD"/replace-editor.sh\" &&
257 + test_tick &&
258 + git rebase -i --force --root -r &&
259 + test "Parsnip" = "$(git show -s --format=%an HEAD^)" &&
260 + test $(git rev-parse second-root^0) != $(git rev-parse HEAD^) &&
261 + test $(git rev-parse second-root:second-root.t) = \
262 + $(git rev-parse HEAD^:second-root.t) &&
263 + test_cmp_graph HEAD <<-\EOF &&
264 + * Merge the 3rd root
265 + |\
266 + | * third-root
267 + * second-root
268 + EOF
269 +
270 + : fast forward if possible &&
271 + before="$(git rev-parse --verify HEAD)" &&
272 + test_might_fail git config --unset sequence.editor &&
273 + test_tick &&
274 + git rebase -i --root -r &&
275 + test_cmp_rev HEAD $before
276 +'
277 +
278 test_done