From d87d48b2e033e8a8d39afbe7cb5eea331bbe47a6 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Fri, 4 May 2018 01:01:17 +0200 Subject: [PATCH] sequencer: learn about the special "fake root commit" handling When an interactive rebase wants to recreate a root commit, it - first creates a new, empty root commit, - checks it out, - converts the next `pick` command so that it amends the empty root commit Introduce support in the sequencer to handle such an empty root commit, by looking for the file /rebase-merge/squash-onto; if it exists and contains a commit name, the sequencer will compare the HEAD to said root commit, and if identical, a new root commit will be created. While converting scripted code into proper, portable C, we also do away with the old "amend with an empty commit message, then cherry-pick without committing, then amend again" dance and replace it with code that uses the internal API properly to do exactly what we want: create a new root commit. To keep the implementation simple, we always spawn `git commit` to create new root commits. Signed-off-by: Johannes Schindelin Signed-off-by: Junio C Hamano --- sequencer.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- sequencer.h | 4 ++ 2 files changed, 125 insertions(+), 3 deletions(-) diff --git a/sequencer.c b/sequencer.c index 90c8218aa9..8eddda681d 100644 --- a/sequencer.c +++ b/sequencer.c @@ -126,6 +126,12 @@ static GIT_PATH_FUNC(rebase_path_rewritten_pending, "rebase-merge/rewritten-pending") /* + * The path of the file containig the OID of the "squash onto" commit, i.e. + * the dummy commit used for `reset [new root]`. + */ +static GIT_PATH_FUNC(rebase_path_squash_onto, "rebase-merge/squash-onto") + +/* * The path of the file listing refs that need to be deleted after the rebase * finishes. This is used by the `label` command to record the need for cleanup. */ @@ -470,7 +476,8 @@ static int fast_forward_to(const struct object_id *to, const struct object_id *f transaction = ref_transaction_begin(&err); if (!transaction || ref_transaction_update(transaction, "HEAD", - to, unborn ? &null_oid : from, + to, unborn && !is_rebase_i(opts) ? + &null_oid : from, 0, sb.buf, &err) || ref_transaction_commit(transaction, &err)) { ref_transaction_free(transaction); @@ -692,6 +699,52 @@ static char *get_author(const char *message) return NULL; } +/* Read author-script and return an ident line (author timestamp) */ +static const char *read_author_ident(struct strbuf *buf) +{ + const char *keys[] = { + "GIT_AUTHOR_NAME=", "GIT_AUTHOR_EMAIL=", "GIT_AUTHOR_DATE=" + }; + char *in, *out, *eol; + int i = 0, len; + + if (strbuf_read_file(buf, rebase_path_author_script(), 256) <= 0) + return NULL; + + /* dequote values and construct ident line in-place */ + for (in = out = buf->buf; i < 3 && in - buf->buf < buf->len; i++) { + if (!skip_prefix(in, keys[i], (const char **)&in)) { + warning("could not parse '%s' (looking for '%s'", + rebase_path_author_script(), keys[i]); + return NULL; + } + + eol = strchrnul(in, '\n'); + *eol = '\0'; + sq_dequote(in); + len = strlen(in); + + if (i > 0) /* separate values by spaces */ + *(out++) = ' '; + if (i == 1) /* email needs to be surrounded by <...> */ + *(out++) = '<'; + memmove(out, in, len); + out += len; + if (i == 1) /* email needs to be surrounded by <...> */ + *(out++) = '>'; + in = eol + 1; + } + + if (i < 3) { + warning("could not parse '%s' (looking for '%s')", + rebase_path_author_script(), keys[i]); + return NULL; + } + + buf->len = out - buf->buf; + return buf->buf; +} + static const char staged_changes_advice[] = N_("you have staged changes in your working tree\n" "If these changes are meant to be squashed into the previous commit, run:\n" @@ -711,6 +764,7 @@ N_("you have staged changes in your working tree\n" #define AMEND_MSG (1<<2) #define CLEANUP_MSG (1<<3) #define VERIFY_MSG (1<<4) +#define CREATE_ROOT_COMMIT (1<<5) /* * If we are cherry-pick, and if the merge did not result in @@ -730,6 +784,40 @@ static int run_git_commit(const char *defmsg, struct replay_opts *opts, struct child_process cmd = CHILD_PROCESS_INIT; const char *value; + if (flags & CREATE_ROOT_COMMIT) { + struct strbuf msg = STRBUF_INIT, script = STRBUF_INIT; + const char *author = is_rebase_i(opts) ? + read_author_ident(&script) : NULL; + struct object_id root_commit, *cache_tree_oid; + int res = 0; + + if (!defmsg) + BUG("root commit without message"); + + if (!(cache_tree_oid = get_cache_tree_oid())) + res = -1; + + if (!res) + res = strbuf_read_file(&msg, defmsg, 0); + + if (res <= 0) + res = error_errno(_("could not read '%s'"), defmsg); + else + res = commit_tree(msg.buf, msg.len, cache_tree_oid, + NULL, &root_commit, author, + opts->gpg_sign); + + strbuf_release(&msg); + strbuf_release(&script); + if (!res) { + update_ref(NULL, "CHERRY_PICK_HEAD", &root_commit, NULL, + REF_NO_DEREF, UPDATE_REFS_MSG_ON_ERR); + res = update_ref(NULL, "HEAD", &root_commit, NULL, 0, + UPDATE_REFS_MSG_ON_ERR); + } + return res < 0 ? error(_("writing root commit")) : 0; + } + cmd.git_cmd = 1; if (is_rebase_i(opts)) { @@ -1216,7 +1304,8 @@ static int do_commit(const char *msg_file, const char *author, { int res = 1; - if (!(flags & EDIT_MSG) && !(flags & VERIFY_MSG)) { + if (!(flags & EDIT_MSG) && !(flags & VERIFY_MSG) && + !(flags & CREATE_ROOT_COMMIT)) { struct object_id oid; struct strbuf sb = STRBUF_INIT; @@ -1369,6 +1458,22 @@ static int is_fixup(enum todo_command command) return command == TODO_FIXUP || command == TODO_SQUASH; } +/* Does this command create a (non-merge) commit? */ +static int is_pick_or_similar(enum todo_command command) +{ + switch (command) { + case TODO_PICK: + case TODO_REVERT: + case TODO_EDIT: + case TODO_REWORD: + case TODO_FIXUP: + case TODO_SQUASH: + return 1; + default: + return 0; + } +} + static int update_squash_messages(enum todo_command command, struct commit *commit, struct replay_opts *opts) { @@ -1523,7 +1628,14 @@ static int do_pick_commit(enum todo_command command, struct commit *commit, return error(_("your index file is unmerged.")); } else { unborn = get_oid("HEAD", &head); - if (unborn) + /* Do we want to generate a root commit? */ + if (is_pick_or_similar(command) && opts->have_squash_onto && + !oidcmp(&head, &opts->squash_onto)) { + if (is_fixup(command)) + return error(_("cannot fixup root commit")); + flags |= CREATE_ROOT_COMMIT; + unborn = 1; + } else if (unborn) oidcpy(&head, the_hash_algo->empty_tree); if (index_differs_from(unborn ? EMPTY_TREE_SHA1_HEX : "HEAD", NULL, 0)) @@ -2136,6 +2248,12 @@ static int read_populate_opts(struct replay_opts *opts) read_strategy_opts(opts, &buf); strbuf_release(&buf); + if (read_oneliner(&buf, rebase_path_squash_onto(), 0)) { + if (get_oid_hex(buf.buf, &opts->squash_onto) < 0) + return error(_("unusable squash-onto")); + opts->have_squash_onto = 1; + } + return 0; } diff --git a/sequencer.h b/sequencer.h index d9570d92b1..4b2717881f 100644 --- a/sequencer.h +++ b/sequencer.h @@ -44,6 +44,10 @@ struct replay_opts { char **xopts; size_t xopts_nr, xopts_alloc; + /* placeholder commit for -i --root */ + struct object_id squash_onto; + int have_squash_onto; + /* Only used by REPLAY_NONE */ struct rev_info *revs; }; -- 2.11.4.GIT