"Johannes Schindelin via GitGitGadget" <gitgitgadget@xxxxxxxxx>
writes:
> +static char *remote_default_branch(const char *url)
> +{
> + struct child_process cp = CHILD_PROCESS_INIT;
> + struct strbuf out = STRBUF_INIT;
> +
> + cp.git_cmd = 1;
> + strvec_pushl(&cp.args, "ls-remote", "--symref", url, "HEAD", NULL);
> + strbuf_addstr(&out, "-\n");
Is this a workaround for the problem that the first "ref:" line
won't be found by looking for "\nref: " in the loop? Cute, but the
extra "-" is a bit misleading.
> + if (!pipe_command(&cp, NULL, 0, &out, 0, NULL, 0)) {
> + char *ref = out.buf;
> +
> + while ((ref = strstr(ref + 1, "\nref: "))) {
> + const char *p;
> + char *head, *branch;
> +
> + ref += strlen("\nref: ");
> + head = strstr(ref, "\tHEAD");
> +
> + if (!head || memchr(ref, '\n', head - ref))
> + continue;
OK. We expect "ref: " <refname> "\t" <head> "\n" where <head> is
"HEAD" for their .git/HEAD and refs/remotes/<nick>/HEAD for their
remote-tracking branch for the remote they call <nick>, on a single
line. We reject a line that is not of that shape, and we reject a
line that is about remote-tracking branch by only looking for
"\tHEAD". Makes sense.
The strstr() goes from "ref + 1", which feels sloppy. When we
reject the line we found that begins with "ref :", I would have
expected that the next scan would start at the beginning of the next
line, not from the middle of this line at the first letter 'e' in
'refs/heads/' on the current line "ref: refs/heads/.....". As long
as the current line is long enough, strstr() would not miss the
beginning of the next line, so it might be OK.
> + if (skip_prefix(ref, "refs/heads/", &p)) {
> + branch = xstrndup(p, head - p);
> + strbuf_release(&out);
> + return branch;
> + }
> +
> + error(_("remote HEAD is not a branch: '%.*s'"),
> + (int)(head - ref), ref);
> + strbuf_release(&out);
> + return NULL;
OK. Any symref whose basename is HEAD in their remote-tracking
hierarchy would have been rejected earlier in the loop.
Is there a particular reason why we return early here, instead of
breaking out of hte loop and let the generic "failed to get" code
path below to handle this case?
> + }
> + }
> + warning(_("failed to get default branch name from remote; "
> + "using local default"));
> + strbuf_reset(&out);
> +
> + child_process_init(&cp);
> + cp.git_cmd = 1;
> + strvec_pushl(&cp.args, "symbolic-ref", "--short", "HEAD", NULL);
> + if (!pipe_command(&cp, NULL, 0, &out, 0, NULL, 0)) {
> + strbuf_trim(&out);
> + return strbuf_detach(&out, NULL);
> + }
> +
> + strbuf_release(&out);
> + error(_("failed to get default branch name"));
> + return NULL;
> +}
> +static int cmd_clone(int argc, const char **argv)
> +{
> + const char *branch = NULL;
> + int full_clone = 0;
> + struct option clone_options[] = {
> + OPT_STRING('b', "branch", &branch, N_("<branch>"),
> + N_("branch to checkout after clone")),
> + OPT_BOOL(0, "full-clone", &full_clone,
> + N_("when cloning, create full working directory")),
> + OPT_END(),
> + };
> + const char * const clone_usage[] = {
> + N_("scalar clone [<options>] [--] <repo> [<dir>]"),
> + NULL
> + };
> + const char *url;
> + char *enlistment = NULL, *dir = NULL;
> + struct strbuf buf = STRBUF_INIT;
> + int res;
> +
> + argc = parse_options(argc, argv, NULL, clone_options, clone_usage, 0);
> +
> + if (argc == 2) {
> + url = argv[0];
> + enlistment = xstrdup(argv[1]);
> + } else if (argc == 1) {
> + url = argv[0];
> +
> + strbuf_addstr(&buf, url);
> + /* Strip trailing slashes, if any */
> + while (buf.len > 0 && is_dir_sep(buf.buf[buf.len - 1]))
> + strbuf_setlen(&buf, buf.len - 1);
> + /* Strip suffix `.git`, if any */
> + strbuf_strip_suffix(&buf, ".git");
> +
> + enlistment = find_last_dir_sep(buf.buf);
> + if (!enlistment) {
> + die(_("cannot deduce worktree name from '%s'"), url);
> + }
> + enlistment = xstrdup(enlistment + 1);
> + } else {
> + usage_msg_opt(_("You must specify a repository to clone."),
> + clone_usage, clone_options);
> + }
> +
> + if (is_directory(enlistment))
> + die(_("directory '%s' exists already"), enlistment);
> +
> + dir = xstrfmt("%s/src", enlistment);
> +
> + strbuf_reset(&buf);
> + if (branch)
> + strbuf_addf(&buf, "init.defaultBranch=%s", branch);
> + else {
> + char *b = repo_default_branch_name(the_repository, 1);
> + strbuf_addf(&buf, "init.defaultBranch=%s", b);
> + free(b);
Doesn't "git clone" already use their HEAD without having to make an
extra "git ls-remote" roundtrip?
Ahh, you do not do "git clone"; you do "git init", set things up,
and then "git fetch" and checkout, all manually.
Which is kind of shame.
I wonder if it is a cleaner implementation to give a new option to
"git clone" that gives a command sequence (not necessarily have to
be implemented as a shell script) that specifies necessary
pre-configuration steps to be done before the command starts the
transfer step.
