On 2021.12.07 11:28, Junio C Hamano wrote:
> Josh Steadmon <steadmon@xxxxxxxxxx> writes:
>
> > +static int install_branch_config_multiple_remotes(int flag, const char *local, const char *origin,
> > + struct string_list *remotes)
>
> The line got overly long so perhaps cut the line after "*local,",
> as "origin" and "remotes" conceptually are closer together.
>
> What is in the string list? Names of refs at the remote "origin",
> instead of a single ref there?
Added a comment explaining the purpose and arguments.
> > {
> > const char *shortname = NULL;
> > struct strbuf key = STRBUF_INIT;
> > - int rebasing = should_setup_rebase(origin);
> > -
> > - if (skip_prefix(remote, "refs/heads/", &shortname)
> > - && !strcmp(local, shortname)
> > - && !origin) {
> > - warning(_("Not setting branch %s as its own upstream."),
> > - local);
>
> When 'origin' is NULL in the original caller, it means a local
> tracking, and making sure we do not say "my 'master' branch builds
> on top of itself" makes sense.
>
> > - return 0;
> > - }
> > + int i, rebasing = should_setup_rebase(origin);
> > +
> > + if (remotes->nr < 1)
> > + BUG("must provide at least one remote for branch config");
> > +
> > + if (!origin)
> > + for (i = 0; i < remotes->nr; i++)
> > + if (skip_prefix(remotes->items[i].string, "refs/heads/", &shortname)
> > + && !strcmp(local, shortname)) {
> > + warning(_("Not setting branch %s as its own upstream."),
> > + local);
> > + return 0;
>
> I am a bit surprised with this warning and early return before
> inspecting the remainder of the list. When 'origin' is NULL,
> i.e. we are talking about the local building on top of another local
> branch, if the function is called for the local branch 'main' with
> 'main' in the remotes list alone, we do want to issue the warning
> and exit without doing anything (i.e. degenerating to the original
> behaviour of taking a single string variable, when a string list
> with a single element is given). But if the remotes list has 'main'
> and 'master', would we want to just "skip" the same one, but still
> handle the other ones as if the "same" branch were not in the list?
The inheritance case when creating a new branch is the only time we get
multiple branches, and I think it is a sign of a wider misconfiguration
if we have our own branch name listed as upstream in this case.
When inheriting, `local` should always be a new branch, and `remotes`
should contain the `branch.<name>.merge` entries of the branch we're
inheriting from. For this check to trigger would mean that the parent
branch has configured a local upstream branch that doesn't actually
exist. So it seems that something has gone wrong; perhaps we can assume
what the user wanted such as in your case above, but it seems to me that
it's safer to warn when this happens.
> > @@ -75,8 +80,17 @@ int install_branch_config(int flag, const char *local, const char *origin, const
> >
> > strbuf_reset(&key);
> > strbuf_addf(&key, "branch.%s.merge", local);
> > - if (git_config_set_gently(key.buf, remote) < 0)
> > + /*
> > + * We want to overwrite any existing config with all the branches in
> > + * "remotes". Override any existing config with the first branch, but if
> > + * more than one is provided, use CONFIG_REGEX_NONE to preserve what
> > + * we've written so far.
> > + */
> > + if (git_config_set_gently(key.buf, remotes->items[0].string) < 0)
> > goto out_err;
> > + for (i = 1; i < remotes->nr; i++)
> > + if (git_config_set_multivar_gently(key.buf, remotes->items[i].string, CONFIG_REGEX_NONE, 0) < 0)
> > + goto out_err;
> >
> > if (rebasing) {
> > strbuf_reset(&key);
> > @@ -87,29 +101,62 @@ int install_branch_config(int flag, const char *local, const char *origin, const
> > strbuf_release(&key);
> >
> > if (flag & BRANCH_CONFIG_VERBOSE) {
> > - if (shortname) {
> > - if (origin)
> > - printf_ln(rebasing ?
> > - _("Branch '%s' set up to track remote branch '%s' from '%s' by rebasing.") :
> > - _("Branch '%s' set up to track remote branch '%s' from '%s'."),
> > - local, shortname, origin);
> > - else
> > - printf_ln(rebasing ?
> > - _("Branch '%s' set up to track local branch '%s' by rebasing.") :
> > - _("Branch '%s' set up to track local branch '%s'."),
> > - local, shortname);
> > + int plural = remotes->nr > 1;
> > + int all_shortnames = 1;
> > + const char *msg_fmt;
> > + struct strbuf ref_string = STRBUF_INIT;
> > +
> > + for (i = 0; i < remotes->nr; i++)
> > + if (skip_prefix(remotes->items[i].string, "refs/heads/", &shortname)) {
> > + strbuf_addf(&ref_string, "'%s', ", shortname);
> > + } else {
> > + all_shortnames = 0;
> > + strbuf_addf(&ref_string, "'%s', ", remotes->items[i].string);
>
> So, all_shortnames == true means everything was a local branch in
> the 'origin' remote, and when it has a non-branch (like a tag),
> all_shortnames becomes false?
>
> > + }
> > + /* The last two characters are an extraneous ", ", so trim those. */
> > + strbuf_setlen(&ref_string, ref_string.len - 2);
>
> As you are starting from an empty ref_string, a more idiomatic way
> to build concatenated string would be to prefix when you add a new
> item, e.g.
>
> loop {
> if (ref_string already has items)
> ref_string.append(", ");
> ref_string.append(this_item);
> }
Ack, although changes to address other review feedback has made this
point moot.
> > + if (all_shortnames && origin) {
> > + if (rebasing && plural)
> > + msg_fmt = "Branch '%s' set up to track remote branches %s from '%s' by rebasing.";
>
> What does it mean to keep my 'topic' branch up-to-date by rebasing
> on top of more than one remote sources? By merging, I can sort-of
> understand (i.e. creating an octopus), but would it make sense to
> track more than one remote sources in general? Is it common?
>
> When the benefit is not clear, it might make more sense not to do
> this when there are already multiple tracking sources defined for
> the original; it might be a mistake that we may not want to spread
> with the new option.
>
> Of course, it is very possible that I am missing a perfectly valid
> use case where having more than one makes good sense. If so, please
> do not take the above comments as an objection, but adding some
> comments before the function to explain when having remote list with
> more than one items makes sense and how such a setting can be used
> to avoid future readers asking the same (stupid) question as I just
> did.
No, that's an oversight on my part. This will now exit with an error if
we try to rebase onto multiple branches.
> > + else if (rebasing && !plural)
> > + msg_fmt = "Branch '%s' set up to track remote branch %s from '%s' by rebasing.";
> > + else if (!rebasing && plural)
> > + msg_fmt = "Branch '%s' set up to track remote branches %s from '%s'.";
> > + else if (!rebasing && !plural)
> > + msg_fmt = "Branch '%s' set up to track remote branch %s from '%s'.";
> > +
> > + printf_ln(_(msg_fmt), local, ref_string, origin);
>
> I am not sure how well the "plural" thing works with i18n. It may
> suffice for the original in English to have only two choices between
> one or more-than-one, but not all languages are English. Counting
> the actual number (I guess remotes->nr is it) and using Q_() to
> choose between the possible variants. I think Ævar knows about this
> much better than I do.
>
> But if we are not doing this "set multiple" and instead go the
> "detect existing multiple and refrain from spreading the damage"
> route, all of that is moot.
>
> Thanks.
Thanks for the feedback!
