1 files changed, 622 insertions, 0 deletions

diff --git a/builtin/replace.c b/builtin/replace.c
new file mode 100644
index 000000000000..644b21ca8d57
--- /dev/null
+++ b/builtin/replace.c
@@ -0,0 +1,622 @@
+/*
+ * Builtin "git replace"
+ *
+ * Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>
+ *
+ * Based on builtin/tag.c by Kristian Høgsberg <krh@redhat.com>
+ * and Carlos Rica <jasampler@gmail.com> that was itself based on
+ * git-tag.sh and mktag.c by Linus Torvalds.
+ */
+
+#include "cache.h"
+#include "config.h"
+#include "builtin.h"
+#include "refs.h"
+#include "parse-options.h"
+#include "run-command.h"
+#include "object-store.h"
+#include "repository.h"
+#include "tag.h"
+
+static const char * const git_replace_usage[] = {
+	N_("git replace [-f] <object> <replacement>"),
+	N_("git replace [-f] --edit <object>"),
+	N_("git replace [-f] --graft <commit> [<parent>...]"),
+	N_("git replace [-f] --convert-graft-file"),
+	N_("git replace -d <object>..."),
+	N_("git replace [--format=<format>] [-l [<pattern>]]"),
+	NULL
+};
+
+enum replace_format {
+	REPLACE_FORMAT_SHORT,
+	REPLACE_FORMAT_MEDIUM,
+	REPLACE_FORMAT_LONG
+};
+
+struct show_data {
+	const char *pattern;
+	enum replace_format format;
+};
+
+static int show_reference(struct repository *r, const char *refname,
+			  const struct object_id *oid,
+			  int flag, void *cb_data)
+{
+	struct show_data *data = cb_data;
+
+	if (!wildmatch(data->pattern, refname, 0)) {
+		if (data->format == REPLACE_FORMAT_SHORT)
+			printf("%s\n", refname);
+		else if (data->format == REPLACE_FORMAT_MEDIUM)
+			printf("%s -> %s\n", refname, oid_to_hex(oid));
+		else { /* data->format == REPLACE_FORMAT_LONG */
+			struct object_id object;
+			enum object_type obj_type, repl_type;
+
+			if (get_oid(refname, &object))
+				return error(_("failed to resolve '%s' as a valid ref"), refname);
+
+			obj_type = oid_object_info(r, &object, NULL);
+			repl_type = oid_object_info(r, oid, NULL);
+
+			printf("%s (%s) -> %s (%s)\n", refname, type_name(obj_type),
+			       oid_to_hex(oid), type_name(repl_type));
+		}
+	}
+
+	return 0;
+}
+
+static int list_replace_refs(const char *pattern, const char *format)
+{
+	struct show_data data;
+
+	if (pattern == NULL)
+		pattern = "*";
+	data.pattern = pattern;
+
+	if (format == NULL || *format == '\0' || !strcmp(format, "short"))
+		data.format = REPLACE_FORMAT_SHORT;
+	else if (!strcmp(format, "medium"))
+		data.format = REPLACE_FORMAT_MEDIUM;
+	else if (!strcmp(format, "long"))
+		data.format = REPLACE_FORMAT_LONG;
+	/*
+	 * Please update _git_replace() in git-completion.bash when
+	 * you add new format
+	 */
+	else
+		return error(_("invalid replace format '%s'\n"
+			       "valid formats are 'short', 'medium' and 'long'"),
+			     format);
+
+	for_each_replace_ref(the_repository, show_reference, (void *)&data);
+
+	return 0;
+}
+
+typedef int (*each_replace_name_fn)(const char *name, const char *ref,
+				    const struct object_id *oid);
+
+static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
+{
+	const char **p, *full_hex;
+	struct strbuf ref = STRBUF_INIT;
+	size_t base_len;
+	int had_error = 0;
+	struct object_id oid;
+
+	strbuf_addstr(&ref, git_replace_ref_base);
+	base_len = ref.len;
+
+	for (p = argv; *p; p++) {
+		if (get_oid(*p, &oid)) {
+			error("failed to resolve '%s' as a valid ref", *p);
+			had_error = 1;
+			continue;
+		}
+
+		strbuf_setlen(&ref, base_len);
+		strbuf_addstr(&ref, oid_to_hex(&oid));
+		full_hex = ref.buf + base_len;
+
+		if (read_ref(ref.buf, &oid)) {
+			error(_("replace ref '%s' not found"), full_hex);
+			had_error = 1;
+			continue;
+		}
+		if (fn(full_hex, ref.buf, &oid))
+			had_error = 1;
+	}
+	strbuf_release(&ref);
+	return had_error;
+}
+
+static int delete_replace_ref(const char *name, const char *ref,
+			      const struct object_id *oid)
+{
+	if (delete_ref(NULL, ref, oid, 0))
+		return 1;
+	printf_ln(_("Deleted replace ref '%s'"), name);
+	return 0;
+}
+
+static int check_ref_valid(struct object_id *object,
+			    struct object_id *prev,
+			    struct strbuf *ref,
+			    int force)
+{
+	strbuf_reset(ref);
+	strbuf_addf(ref, "%s%s", git_replace_ref_base, oid_to_hex(object));
+	if (check_refname_format(ref->buf, 0))
+		return error(_("'%s' is not a valid ref name"), ref->buf);
+
+	if (read_ref(ref->buf, prev))
+		oidclr(prev);
+	else if (!force)
+		return error(_("replace ref '%s' already exists"), ref->buf);
+	return 0;
+}
+
+static int replace_object_oid(const char *object_ref,
+			       struct object_id *object,
+			       const char *replace_ref,
+			       struct object_id *repl,
+			       int force)
+{
+	struct object_id prev;
+	enum object_type obj_type, repl_type;
+	struct strbuf ref = STRBUF_INIT;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
+	int res = 0;
+
+	obj_type = oid_object_info(the_repository, object, NULL);
+	repl_type = oid_object_info(the_repository, repl, NULL);
+	if (!force && obj_type != repl_type)
+		return error(_("Objects must be of the same type.\n"
+			       "'%s' points to a replaced object of type '%s'\n"
+			       "while '%s' points to a replacement object of "
+			       "type '%s'."),
+			     object_ref, type_name(obj_type),
+			     replace_ref, type_name(repl_type));
+
+	if (check_ref_valid(object, &prev, &ref, force)) {
+		strbuf_release(&ref);
+		return -1;
+	}
+
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, ref.buf, repl, &prev,
+				   0, NULL, &err) ||
+	    ref_transaction_commit(transaction, &err))
+		res = error("%s", err.buf);
+
+	ref_transaction_free(transaction);
+	strbuf_release(&ref);
+	return res;
+}
+
+static int replace_object(const char *object_ref, const char *replace_ref, int force)
+{
+	struct object_id object, repl;
+
+	if (get_oid(object_ref, &object))
+		return error(_("failed to resolve '%s' as a valid ref"),
+			     object_ref);
+	if (get_oid(replace_ref, &repl))
+		return error(_("failed to resolve '%s' as a valid ref"),
+			     replace_ref);
+
+	return replace_object_oid(object_ref, &object, replace_ref, &repl, force);
+}
+
+/*
+ * Write the contents of the object named by "sha1" to the file "filename".
+ * If "raw" is true, then the object's raw contents are printed according to
+ * "type". Otherwise, we pretty-print the contents for human editing.
+ */
+static int export_object(const struct object_id *oid, enum object_type type,
+			  int raw, const char *filename)
+{
+	struct child_process cmd = CHILD_PROCESS_INIT;
+	int fd;
+
+	fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
+	if (fd < 0)
+		return error_errno(_("unable to open %s for writing"), filename);
+
+	argv_array_push(&cmd.args, "--no-replace-objects");
+	argv_array_push(&cmd.args, "cat-file");
+	if (raw)
+		argv_array_push(&cmd.args, type_name(type));
+	else
+		argv_array_push(&cmd.args, "-p");
+	argv_array_push(&cmd.args, oid_to_hex(oid));
+	cmd.git_cmd = 1;
+	cmd.out = fd;
+
+	if (run_command(&cmd))
+		return error(_("cat-file reported failure"));
+	return 0;
+}
+
+/*
+ * Read a previously-exported (and possibly edited) object back from "filename",
+ * interpreting it as "type", and writing the result to the object database.
+ * The sha1 of the written object is returned via sha1.
+ */
+static int import_object(struct object_id *oid, enum object_type type,
+			  int raw, const char *filename)
+{
+	int fd;
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0)
+		return error_errno(_("unable to open %s for reading"), filename);
+
+	if (!raw && type == OBJ_TREE) {
+		const char *argv[] = { "mktree", NULL };
+		struct child_process cmd = CHILD_PROCESS_INIT;
+		struct strbuf result = STRBUF_INIT;
+
+		cmd.argv = argv;
+		cmd.git_cmd = 1;
+		cmd.in = fd;
+		cmd.out = -1;
+
+		if (start_command(&cmd)) {
+			close(fd);
+			return error(_("unable to spawn mktree"));
+		}
+
+		if (strbuf_read(&result, cmd.out, 41) < 0) {
+			error_errno(_("unable to read from mktree"));
+			close(fd);
+			close(cmd.out);
+			return -1;
+		}
+		close(cmd.out);
+
+		if (finish_command(&cmd)) {
+			strbuf_release(&result);
+			return error(_("mktree reported failure"));
+		}
+		if (get_oid_hex(result.buf, oid) < 0) {
+			strbuf_release(&result);
+			return error(_("mktree did not return an object name"));
+		}
+
+		strbuf_release(&result);
+	} else {
+		struct stat st;
+		int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
+
+		if (fstat(fd, &st) < 0) {
+			error_errno(_("unable to fstat %s"), filename);
+			close(fd);
+			return -1;
+		}
+		if (index_fd(the_repository->index, oid, fd, &st, type, NULL, flags) < 0)
+			return error(_("unable to write object to database"));
+		/* index_fd close()s fd for us */
+	}
+
+	/*
+	 * No need to close(fd) here; both run-command and index-fd
+	 * will have done it for us.
+	 */
+	return 0;
+}
+
+static int edit_and_replace(const char *object_ref, int force, int raw)
+{
+	char *tmpfile;
+	enum object_type type;
+	struct object_id old_oid, new_oid, prev;
+	struct strbuf ref = STRBUF_INIT;
+
+	if (get_oid(object_ref, &old_oid) < 0)
+		return error(_("not a valid object name: '%s'"), object_ref);
+
+	type = oid_object_info(the_repository, &old_oid, NULL);
+	if (type < 0)
+		return error(_("unable to get object type for %s"),
+			     oid_to_hex(&old_oid));
+
+	if (check_ref_valid(&old_oid, &prev, &ref, force)) {
+		strbuf_release(&ref);
+		return -1;
+	}
+	strbuf_release(&ref);
+
+	tmpfile = git_pathdup("REPLACE_EDITOBJ");
+	if (export_object(&old_oid, type, raw, tmpfile)) {
+		free(tmpfile);
+		return -1;
+	}
+	if (launch_editor(tmpfile, NULL, NULL) < 0) {
+		free(tmpfile);
+		return error(_("editing object file failed"));
+	}
+	if (import_object(&new_oid, type, raw, tmpfile)) {
+		free(tmpfile);
+		return -1;
+	}
+	free(tmpfile);
+
+	if (oideq(&old_oid, &new_oid))
+		return error(_("new object is the same as the old one: '%s'"), oid_to_hex(&old_oid));
+
+	return replace_object_oid(object_ref, &old_oid, "replacement", &new_oid, force);
+}
+
+static int replace_parents(struct strbuf *buf, int argc, const char **argv)
+{
+	struct strbuf new_parents = STRBUF_INIT;
+	const char *parent_start, *parent_end;
+	int i;
+
+	/* find existing parents */
+	parent_start = buf->buf;
+	parent_start += GIT_SHA1_HEXSZ + 6; /* "tree " + "hex sha1" + "\n" */
+	parent_end = parent_start;
+
+	while (starts_with(parent_end, "parent "))
+		parent_end += 48; /* "parent " + "hex sha1" + "\n" */
+
+	/* prepare new parents */
+	for (i = 0; i < argc; i++) {
+		struct object_id oid;
+		struct commit *commit;
+
+		if (get_oid(argv[i], &oid) < 0) {
+			strbuf_release(&new_parents);
+			return error(_("not a valid object name: '%s'"),
+				     argv[i]);
+		}
+		commit = lookup_commit_reference(the_repository, &oid);
+		if (!commit) {
+			strbuf_release(&new_parents);
+			return error(_("could not parse %s as a commit"), argv[i]);
+		}
+		strbuf_addf(&new_parents, "parent %s\n", oid_to_hex(&commit->object.oid));
+	}
+
+	/* replace existing parents with new ones */
+	strbuf_splice(buf, parent_start - buf->buf, parent_end - parent_start,
+		      new_parents.buf, new_parents.len);
+
+	strbuf_release(&new_parents);
+	return 0;
+}
+
+struct check_mergetag_data {
+	int argc;
+	const char **argv;
+};
+
+static int check_one_mergetag(struct commit *commit,
+			       struct commit_extra_header *extra,
+			       void *data)
+{
+	struct check_mergetag_data *mergetag_data = (struct check_mergetag_data *)data;
+	const char *ref = mergetag_data->argv[0];
+	struct object_id tag_oid;
+	struct tag *tag;
+	int i;
+
+	hash_object_file(extra->value, extra->len, type_name(OBJ_TAG), &tag_oid);
+	tag = lookup_tag(the_repository, &tag_oid);
+	if (!tag)
+		return error(_("bad mergetag in commit '%s'"), ref);
+	if (parse_tag_buffer(the_repository, tag, extra->value, extra->len))
+		return error(_("malformed mergetag in commit '%s'"), ref);
+
+	/* iterate over new parents */
+	for (i = 1; i < mergetag_data->argc; i++) {
+		struct object_id oid;
+		if (get_oid(mergetag_data->argv[i], &oid) < 0)
+			return error(_("not a valid object name: '%s'"),
+				     mergetag_data->argv[i]);
+		if (oideq(&tag->tagged->oid, &oid))
+			return 0; /* found */
+	}
+
+	return error(_("original commit '%s' contains mergetag '%s' that is "
+		       "discarded; use --edit instead of --graft"), ref,
+		     oid_to_hex(&tag_oid));
+}
+
+static int check_mergetags(struct commit *commit, int argc, const char **argv)
+{
+	struct check_mergetag_data mergetag_data;
+
+	mergetag_data.argc = argc;
+	mergetag_data.argv = argv;
+	return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
+}
+
+static int create_graft(int argc, const char **argv, int force, int gentle)
+{
+	struct object_id old_oid, new_oid;
+	const char *old_ref = argv[0];
+	struct commit *commit;
+	struct strbuf buf = STRBUF_INIT;
+	const char *buffer;
+	unsigned long size;
+
+	if (get_oid(old_ref, &old_oid) < 0)
+		return error(_("not a valid object name: '%s'"), old_ref);
+	commit = lookup_commit_reference(the_repository, &old_oid);
+	if (!commit)
+		return error(_("could not parse %s"), old_ref);
+
+	buffer = get_commit_buffer(commit, &size);
+	strbuf_add(&buf, buffer, size);
+	unuse_commit_buffer(commit, buffer);
+
+	if (replace_parents(&buf, argc - 1, &argv[1]) < 0) {
+		strbuf_release(&buf);
+		return -1;
+	}
+
+	if (remove_signature(&buf)) {
+		warning(_("the original commit '%s' has a gpg signature"), old_ref);
+		warning(_("the signature will be removed in the replacement commit!"));
+	}
+
+	if (check_mergetags(commit, argc, argv)) {
+		strbuf_release(&buf);
+		return -1;
+	}
+
+	if (write_object_file(buf.buf, buf.len, commit_type, &new_oid)) {
+		strbuf_release(&buf);
+		return error(_("could not write replacement commit for: '%s'"),
+			     old_ref);
+	}
+
+	strbuf_release(&buf);
+
+	if (oideq(&commit->object.oid, &new_oid)) {
+		if (gentle) {
+			warning(_("graft for '%s' unnecessary"),
+				oid_to_hex(&commit->object.oid));
+			return 0;
+		}
+		return error(_("new commit is the same as the old one: '%s'"),
+			     oid_to_hex(&commit->object.oid));
+	}
+
+	return replace_object_oid(old_ref, &commit->object.oid,
+				  "replacement", &new_oid, force);
+}
+
+static int convert_graft_file(int force)
+{
+	const char *graft_file = get_graft_file(the_repository);
+	FILE *fp = fopen_or_warn(graft_file, "r");
+	struct strbuf buf = STRBUF_INIT, err = STRBUF_INIT;
+	struct argv_array args = ARGV_ARRAY_INIT;
+
+	if (!fp)
+		return -1;
+
+	advice_graft_file_deprecated = 0;
+	while (strbuf_getline(&buf, fp) != EOF) {
+		if (*buf.buf == '#')
+			continue;
+
+		argv_array_split(&args, buf.buf);
+		if (args.argc && create_graft(args.argc, args.argv, force, 1))
+			strbuf_addf(&err, "\n\t%s", buf.buf);
+		argv_array_clear(&args);
+	}
+	fclose(fp);
+
+	strbuf_release(&buf);
+
+	if (!err.len)
+		return unlink_or_warn(graft_file);
+
+	warning(_("could not convert the following graft(s):\n%s"), err.buf);
+	strbuf_release(&err);
+
+	return -1;
+}
+
+int cmd_replace(int argc, const char **argv, const char *prefix)
+{
+	int force = 0;
+	int raw = 0;
+	const char *format = NULL;
+	enum {
+		MODE_UNSPECIFIED = 0,
+		MODE_LIST,
+		MODE_DELETE,
+		MODE_EDIT,
+		MODE_GRAFT,
+		MODE_CONVERT_GRAFT_FILE,
+		MODE_REPLACE
+	} cmdmode = MODE_UNSPECIFIED;
+	struct option options[] = {
+		OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
+		OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
+		OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
+		OPT_CMDMODE('g', "graft", &cmdmode, N_("change a commit's parents"), MODE_GRAFT),
+		OPT_CMDMODE(0, "convert-graft-file", &cmdmode, N_("convert existing graft file"), MODE_CONVERT_GRAFT_FILE),
+		OPT_BOOL_F('f', "force", &force, N_("replace the ref if it exists"),
+			   PARSE_OPT_NOCOMPLETE),
+		OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
+		OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
+		OPT_END()
+	};
+
+	read_replace_refs = 0;
+	git_config(git_default_config, NULL);
+
+	argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
+
+	if (!cmdmode)
+		cmdmode = argc ? MODE_REPLACE : MODE_LIST;
+
+	if (format && cmdmode != MODE_LIST)
+		usage_msg_opt(_("--format cannot be used when not listing"),
+			      git_replace_usage, options);
+
+	if (force &&
+	    cmdmode != MODE_REPLACE &&
+	    cmdmode != MODE_EDIT &&
+	    cmdmode != MODE_GRAFT &&
+	    cmdmode != MODE_CONVERT_GRAFT_FILE)
+		usage_msg_opt(_("-f only makes sense when writing a replacement"),
+			      git_replace_usage, options);
+
+	if (raw && cmdmode != MODE_EDIT)
+		usage_msg_opt(_("--raw only makes sense with --edit"),
+			      git_replace_usage, options);
+
+	switch (cmdmode) {
+	case MODE_DELETE:
+		if (argc < 1)
+			usage_msg_opt(_("-d needs at least one argument"),
+				      git_replace_usage, options);
+		return for_each_replace_name(argv, delete_replace_ref);
+
+	case MODE_REPLACE:
+		if (argc != 2)
+			usage_msg_opt(_("bad number of arguments"),
+				      git_replace_usage, options);
+		return replace_object(argv[0], argv[1], force);
+
+	case MODE_EDIT:
+		if (argc != 1)
+			usage_msg_opt(_("-e needs exactly one argument"),
+				      git_replace_usage, options);
+		return edit_and_replace(argv[0], force, raw);
+
+	case MODE_GRAFT:
+		if (argc < 1)
+			usage_msg_opt(_("-g needs at least one argument"),
+				      git_replace_usage, options);
+		return create_graft(argc, argv, force, 0);
+
+	case MODE_CONVERT_GRAFT_FILE:
+		if (argc != 0)
+			usage_msg_opt(_("--convert-graft-file takes no argument"),
+				      git_replace_usage, options);
+		return !!convert_graft_file(force);
+
+	case MODE_LIST:
+		if (argc > 1)
+			usage_msg_opt(_("only one pattern can be given with -l"),
+				      git_replace_usage, options);
+		return list_replace_refs(argv[0], format);
+
+	default:
+		BUG("invalid cmdmode %d", (int)cmdmode);
+	}
+}