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![Jeff King](/assets/img/avatar_default.png)
The --fork-point option looks in the reflog to try to find where a derived branch forked from a base branch. However, if the reflog for the base branch is totally empty (as it commonly is right after cloning, which does not write a reflog entry), then our for_each_reflog call will not find any entries, and we will come up with no merge base, even though there may be one with the current tip of the base. We can fix this by just adding the current tip to our list of collected entries. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
263 lines
6 KiB
C
263 lines
6 KiB
C
#include "builtin.h"
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#include "cache.h"
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#include "commit.h"
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#include "refs.h"
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#include "diff.h"
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#include "revision.h"
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#include "parse-options.h"
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static int show_merge_base(struct commit **rev, int rev_nr, int show_all)
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{
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struct commit_list *result;
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result = get_merge_bases_many_dirty(rev[0], rev_nr - 1, rev + 1);
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if (!result)
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return 1;
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while (result) {
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printf("%s\n", oid_to_hex(&result->item->object.oid));
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if (!show_all)
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return 0;
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result = result->next;
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}
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return 0;
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}
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static const char * const merge_base_usage[] = {
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N_("git merge-base [-a | --all] <commit> <commit>..."),
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N_("git merge-base [-a | --all] --octopus <commit>..."),
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N_("git merge-base --independent <commit>..."),
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N_("git merge-base --is-ancestor <commit> <commit>"),
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N_("git merge-base --fork-point <ref> [<commit>]"),
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NULL
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};
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static struct commit *get_commit_reference(const char *arg)
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{
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unsigned char revkey[20];
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struct commit *r;
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if (get_sha1(arg, revkey))
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die("Not a valid object name %s", arg);
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r = lookup_commit_reference(revkey);
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if (!r)
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die("Not a valid commit name %s", arg);
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return r;
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}
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static int handle_independent(int count, const char **args)
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{
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struct commit_list *revs = NULL;
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struct commit_list *result;
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int i;
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for (i = count - 1; i >= 0; i--)
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commit_list_insert(get_commit_reference(args[i]), &revs);
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result = reduce_heads(revs);
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if (!result)
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return 1;
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while (result) {
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printf("%s\n", oid_to_hex(&result->item->object.oid));
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result = result->next;
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}
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return 0;
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}
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static int handle_octopus(int count, const char **args, int show_all)
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{
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struct commit_list *revs = NULL;
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struct commit_list *result;
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int i;
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for (i = count - 1; i >= 0; i--)
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commit_list_insert(get_commit_reference(args[i]), &revs);
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result = reduce_heads(get_octopus_merge_bases(revs));
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if (!result)
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return 1;
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while (result) {
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printf("%s\n", oid_to_hex(&result->item->object.oid));
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if (!show_all)
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return 0;
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result = result->next;
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}
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return 0;
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}
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static int handle_is_ancestor(int argc, const char **argv)
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{
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struct commit *one, *two;
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if (argc != 2)
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die("--is-ancestor takes exactly two commits");
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one = get_commit_reference(argv[0]);
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two = get_commit_reference(argv[1]);
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if (in_merge_bases(one, two))
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return 0;
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else
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return 1;
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}
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struct rev_collect {
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struct commit **commit;
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int nr;
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int alloc;
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unsigned int initial : 1;
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};
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static void add_one_commit(unsigned char *sha1, struct rev_collect *revs)
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{
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struct commit *commit;
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if (is_null_sha1(sha1))
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return;
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commit = lookup_commit(sha1);
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if (!commit ||
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(commit->object.flags & TMP_MARK) ||
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parse_commit(commit))
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return;
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ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
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revs->commit[revs->nr++] = commit;
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commit->object.flags |= TMP_MARK;
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}
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static int collect_one_reflog_ent(unsigned char *osha1, unsigned char *nsha1,
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const char *ident, unsigned long timestamp,
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int tz, const char *message, void *cbdata)
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{
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struct rev_collect *revs = cbdata;
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if (revs->initial) {
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revs->initial = 0;
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add_one_commit(osha1, revs);
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}
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add_one_commit(nsha1, revs);
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return 0;
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}
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static int handle_fork_point(int argc, const char **argv)
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{
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unsigned char sha1[20];
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char *refname;
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const char *commitname;
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struct rev_collect revs;
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struct commit *derived;
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struct commit_list *bases;
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int i, ret = 0;
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switch (dwim_ref(argv[0], strlen(argv[0]), sha1, &refname)) {
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case 0:
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die("No such ref: '%s'", argv[0]);
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case 1:
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break; /* good */
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default:
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die("Ambiguous refname: '%s'", argv[0]);
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}
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commitname = (argc == 2) ? argv[1] : "HEAD";
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if (get_sha1(commitname, sha1))
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die("Not a valid object name: '%s'", commitname);
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derived = lookup_commit_reference(sha1);
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memset(&revs, 0, sizeof(revs));
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revs.initial = 1;
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for_each_reflog_ent(refname, collect_one_reflog_ent, &revs);
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if (!revs.nr && !get_sha1(refname, sha1))
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add_one_commit(sha1, &revs);
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for (i = 0; i < revs.nr; i++)
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revs.commit[i]->object.flags &= ~TMP_MARK;
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bases = get_merge_bases_many_dirty(derived, revs.nr, revs.commit);
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/*
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* There should be one and only one merge base, when we found
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* a common ancestor among reflog entries.
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*/
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if (!bases || bases->next) {
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ret = 1;
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goto cleanup_return;
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}
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/* And the found one must be one of the reflog entries */
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for (i = 0; i < revs.nr; i++)
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if (&bases->item->object == &revs.commit[i]->object)
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break; /* found */
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if (revs.nr <= i) {
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ret = 1; /* not found */
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goto cleanup_return;
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}
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printf("%s\n", oid_to_hex(&bases->item->object.oid));
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cleanup_return:
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free_commit_list(bases);
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return ret;
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}
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int cmd_merge_base(int argc, const char **argv, const char *prefix)
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{
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struct commit **rev;
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int rev_nr = 0;
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int show_all = 0;
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int cmdmode = 0;
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struct option options[] = {
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OPT_BOOL('a', "all", &show_all, N_("output all common ancestors")),
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OPT_CMDMODE(0, "octopus", &cmdmode,
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N_("find ancestors for a single n-way merge"), 'o'),
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OPT_CMDMODE(0, "independent", &cmdmode,
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N_("list revs not reachable from others"), 'r'),
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OPT_CMDMODE(0, "is-ancestor", &cmdmode,
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N_("is the first one ancestor of the other?"), 'a'),
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OPT_CMDMODE(0, "fork-point", &cmdmode,
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N_("find where <commit> forked from reflog of <ref>"), 'f'),
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OPT_END()
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};
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git_config(git_default_config, NULL);
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argc = parse_options(argc, argv, prefix, options, merge_base_usage, 0);
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if (cmdmode == 'a') {
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if (argc < 2)
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usage_with_options(merge_base_usage, options);
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if (show_all)
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die("--is-ancestor cannot be used with --all");
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return handle_is_ancestor(argc, argv);
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}
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if (cmdmode == 'r' && show_all)
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die("--independent cannot be used with --all");
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if (cmdmode == 'o')
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return handle_octopus(argc, argv, show_all);
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if (cmdmode == 'r')
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return handle_independent(argc, argv);
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if (cmdmode == 'f') {
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if (argc < 1 || 2 < argc)
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usage_with_options(merge_base_usage, options);
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return handle_fork_point(argc, argv);
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}
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if (argc < 2)
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usage_with_options(merge_base_usage, options);
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ALLOC_ARRAY(rev, argc);
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while (argc-- > 0)
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rev[rev_nr++] = get_commit_reference(*argv++);
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return show_merge_base(rev, rev_nr, show_all);
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}
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