On Sun, Jul 19, 2015 at 9:10 AM, Paul Tan <pyokagan@xxxxxxxxx> wrote:
> Since 3e5057a (git am --abort, 2008-07-16), git-am supported the --abort
> option that will rewind HEAD back to the original commit. Re-implement
> this through am_abort().
>
> Since 7b3b7e3 (am --abort: keep unrelated commits since the last failure
> and warn, 2010-12-21), to prevent commits made since the last failure
> from being lost, git-am will not rewind HEAD back to the original
> commit if HEAD moved since the last failure. Re-implement this through
> safe_to_abort().
>
> Signed-off-by: Paul Tan <pyokagan@xxxxxxxxx>
> ---
> builtin/am.c | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 99 insertions(+), 3 deletions(-)
>
> diff --git a/builtin/am.c b/builtin/am.c
> index 765844b..8a054ee 100644
> --- a/builtin/am.c
> +++ b/builtin/am.c
> @@ -490,6 +490,8 @@ static int split_mail(struct am_state *state, enum patch_format patch_format,
> static void am_setup(struct am_state *state, enum patch_format patch_format,
> const char **paths)
> {
> + unsigned char curr_head[GIT_SHA1_RAWSZ];
> +
> if (!patch_format)
> patch_format = detect_patch_format(paths);
>
> @@ -506,6 +508,14 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
> die(_("Failed to split patches."));
> }
>
> + if (!get_sha1("HEAD", curr_head)) {
> + write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(curr_head));
> + update_ref("am", "ORIG_HEAD", curr_head, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
> + } else {
> + write_file(am_path(state, "abort-safety"), 1, "%s", "");
> + delete_ref("ORIG_HEAD", NULL, 0);
> + }
> +
> /*
> * NOTE: Since the "next" and "last" files determine if an am_state
> * session is in progress, they should be written last.
> @@ -522,6 +532,8 @@ static void am_setup(struct am_state *state, enum patch_format patch_format,
> */
> static void am_next(struct am_state *state)
> {
> + unsigned char head[GIT_SHA1_RAWSZ];
> +
> free(state->author_name);
> state->author_name = NULL;
>
> @@ -538,6 +550,11 @@ static void am_next(struct am_state *state)
> unlink(am_path(state, "author-script"));
> unlink(am_path(state, "final-commit"));
>
> + if (!get_sha1("HEAD", head))
> + write_file(am_path(state, "abort-safety"), 1, "%s", sha1_to_hex(head));
> + else
> + write_file(am_path(state, "abort-safety"), 1, "%s", "");
> +
> state->cur++;
> write_file(am_path(state, "next"), 1, "%d", state->cur);
> }
> @@ -788,10 +805,14 @@ static void am_run(struct am_state *state, int resume)
> const char *argv_gc_auto[] = {"gc", "--auto", NULL};
> struct strbuf sb = STRBUF_INIT;
>
> + unlink(am_path(state, "dirtyindex"));
> +
> refresh_and_write_cache();
>
> - if (index_has_changes(&sb))
> + if (index_has_changes(&sb)) {
> + write_file(am_path(state, "dirtyindex"), 1, "t");
> die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
> + }
>
> strbuf_release(&sb);
>
> @@ -980,6 +1001,74 @@ static void am_skip(struct am_state *state)
> }
>
> /**
> + * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
> + *
> + * It is not safe to reset HEAD when:
> + * 1. git-am previously failed because the index was dirty.
> + * 2. HEAD has moved since git-am previously failed.
> + */
> +static int safe_to_abort(const struct am_state *state)
> +{
> + struct strbuf sb = STRBUF_INIT;
> + unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
> +
> + if (file_exists(am_path(state, "dirtyindex")))
> + return 0;
> +
> + if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
> + if (get_sha1_hex(sb.buf, abort_safety))
> + die(_("could not parse %s"), am_path(state, "abort_safety"));
> + } else
> + hashclr(abort_safety);
> +
> + if (get_sha1("HEAD", head))
> + hashclr(head);
> +
> + if (!hashcmp(head, abort_safety))
> + return 1;
> +
> + error(_("You seem to have moved HEAD since the last 'am' failure.\n"
> + "Not rewinding to ORIG_HEAD"));
> +
> + return 0;
> +}
> +
> +/**
> + * Aborts the current am session if it is safe to do so.
> + */
> +static void am_abort(struct am_state *state)
> +{
> + unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
> + int has_curr_head, has_orig_head;
> + const char *curr_branch;
> +
> + if (!safe_to_abort(state)) {
> + am_destroy(state);
> + return;
> + }
> +
> + curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
> + has_curr_head = !is_null_sha1(curr_head);
> + if (!has_curr_head)
> + hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
> +
> + has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
> + if (!has_orig_head)
> + hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
> +
> + clean_index(curr_head, orig_head);
> +
> + if (has_orig_head)
> + update_ref("am --abort", "HEAD", orig_head,
> + has_curr_head ? curr_head : NULL, 0,
> + UPDATE_REFS_DIE_ON_ERR);
> + else if (curr_branch)
> + delete_ref(curr_branch, NULL, REF_NODEREF);
> +
> + am_destroy(state);
free(curr_branch) here?
> +}
> +
> +/**
> * parse_options() callback that validates and sets opt->value to the
> * PATCH_FORMAT_* enum value corresponding to `arg`.
> */
> @@ -998,7 +1087,8 @@ enum resume_mode {
> RESUME_FALSE = 0,
> RESUME_APPLY,
> RESUME_RESOLVED,
> - RESUME_SKIP
> + RESUME_SKIP,
> + RESUME_ABORT
> };
>
> int cmd_am(int argc, const char **argv, const char *prefix)
> @@ -1009,7 +1099,7 @@ int cmd_am(int argc, const char **argv, const char *prefix)
>
> const char * const usage[] = {
> N_("git am [options] [(<mbox>|<Maildir>)...]"),
> - N_("git am [options] (--continue | --skip)"),
> + N_("git am [options] (--continue | --skip | --abort)"),
> NULL
> };
>
> @@ -1026,6 +1116,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
> OPT_CMDMODE(0, "skip", &resume,
> N_("skip the current patch"),
> RESUME_SKIP),
> + OPT_CMDMODE(0, "abort", &resume,
> + N_("restore the original branch and abort the patching operation."),
> + RESUME_ABORT),
> OPT_END()
> };
>
> @@ -1090,6 +1183,9 @@ int cmd_am(int argc, const char **argv, const char *prefix)
> case RESUME_SKIP:
> am_skip(&state);
> break;
> + case RESUME_ABORT:
> + am_abort(&state);
> + break;
> default:
> die("BUG: invalid resume value");
> }
> --
> 2.5.0.rc2.110.gb39b692
>
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