Subject: Re: [PATCH v5 1/2] branch: accept multiple upstream branches for tracking

From: Josh Steadmon <[email-masked]>
Date: Thu, 9 Dec 2021 15:03:11 -0800

On 2021.12.07 09:57, Ævar Arnfjörð Bjarmason wrote:
> 
> On Mon, Dec 06 2021, Josh Steadmon wrote:
> 
> > Add a new static variant of install_branch_config() that accepts
> > multiple remote branch names for tracking. This will be used in an
> > upcoming commit that enables inheriting the tracking configuration from
> > a parent branch.
> >
> > Currently, all callers of install_branch_config() pass only a single
> > remote. Make install_branch_config() a small wrapper around
> > install_branch_config_multiple_remotes() so that existing callers do not
> > need to be changed.
> >
> > Signed-off-by: Josh Steadmon <[email-masked]>
> > ---
> >  branch.c | 120 ++++++++++++++++++++++++++++++++++++++++---------------
> >  1 file changed, 87 insertions(+), 33 deletions(-)
> >
> > diff --git a/branch.c b/branch.c
> > index 7a88a4861e..1aabef4de0 100644
> > --- a/branch.c
> > +++ b/branch.c
> > @@ -55,19 +55,24 @@ N_("\n"
> >  "the remote tracking information by invoking\n"
> >  "\"git branch --set-upstream-to=%s%s%s\".");
> >  
> > -int install_branch_config(int flag, const char *local, const char *origin, const char *remote)
> > +static int install_branch_config_multiple_remotes(int flag, const char *local, const char *origin,
> > +		struct string_list *remotes)
> >  {
> >  	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);
> > -		return 0;
> > -	}
> > +	int i, rebasing = should_setup_rebase(origin);
> > +
> > +	if (remotes->nr < 1)
> > +		BUG("must provide at least one remote for branch config");
> 
> Since it's unsigned IMO this would be clearer: if (!remotes->nr)

Fixed in v6.

> > +
> > +	if (!origin)
> > +		for (i = 0; i < remotes->nr; i++)
> > +			if (skip_prefix(remotes->items[i].string, "refs/heads/", &shortname)
> 
> For this and others, since you don't use the [i] for anything except
> getting the current item using for_each_string_list_item() would be
> better.
> 
> Partially a nit, partially that I've got another WIP
> soon-to-be-submitted topic to fix overflow bugs in that API, and not
> having "int i" etc. hardcoded in various places
> helps. I.e. for_each_string_list_item() is future-proof.

Thanks. I somehow missed for_each_string_list_item() when I checked the
header file. Fixed in v6.

> > +			    && !strcmp(local, shortname)) {
> > +				warning(_("Not setting branch %s as its own upstream."),
> 
> Better to quote '%s', also s/Not/not/ (lower-case) for all error/warning/die etc.

Done (for now) in v6, but this might become moot as I address Junio's
review comments.

> > +					local);
> > +				return 0;
> > +			}
> >  
> >  	strbuf_addf(&key, "branch.%s.remote", local);
> >  	if (git_config_set_gently(key.buf, origin ? origin : ".") < 0)
> > @@ -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;
> 
> This....
> 
> > +		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);
> > +			}
> > +		/* The last two characters are an extraneous ", ", so trim those. */
> > +		strbuf_setlen(&ref_string, ref_string.len - 2);
> 
> languages RTL in around way wrong the be to going is thing of sort This.
> 
> :)
> 
> We deal with this in most other places by just formatting a list of
> branches. E.g. in the ambiguous object output:
> 
>     https://lore.kernel.org/git/[email-masked]/

Done, thanks for the suggestion.

> > +
> > +		if (all_shortnames && origin) {
> > +			if (rebasing && plural)
> > +				msg_fmt = "Branch '%s' set up to track remote branches %s from '%s' by rebasing.";
> > +			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'.";
> 
> ...and this is hardcoding plural rules used in English that don't apply
> in a lot of other languages...
> 
> > +
> > +			printf_ln(_(msg_fmt), local, ref_string, origin);
> >  		} else {
> > -			if (origin)
> > -				printf_ln(rebasing ?
> > -					  _("Branch '%s' set up to track remote ref '%s' by rebasing.") :
> > -					  _("Branch '%s' set up to track remote ref '%s'."),
> > -					  local, remote);
> > -			else
> > -				printf_ln(rebasing ?
> > -					  _("Branch '%s' set up to track local ref '%s' by rebasing.") :
> > -					  _("Branch '%s' set up to track local ref '%s'."),
> > -					  local, remote);
> > +			if (all_shortnames && !origin && rebasing && plural)
> > +				msg_fmt = "Branch '%s' set up to track local branches %s by rebasing.";
> > +			if (all_shortnames && !origin && rebasing && !plural)
> > +				msg_fmt = "Branch '%s' set up to track local branch %s by rebasing.";
> > +			if (all_shortnames && !origin && !rebasing && plural)
> > +				msg_fmt = "Branch '%s' set up to track local branches %s.";
> > +			if (all_shortnames && !origin && !rebasing && !plural)
> > +				msg_fmt = "Branch '%s' set up to track local branch %s.";
> > +			if (!all_shortnames && origin && rebasing && plural)
> > +				msg_fmt = "Branch '%s' set up to track remote refs %s by rebasing.";
> > +			if (!all_shortnames && origin && rebasing && !plural)
> > +				msg_fmt = "Branch '%s' set up to track remote ref %s by rebasing.";
> > +			if (!all_shortnames && origin && !rebasing && plural)
> > +				msg_fmt = "Branch '%s' set up to track remote refs %s.";
> > +			if (!all_shortnames && origin && !rebasing && !plural)
> > +				msg_fmt = "Branch '%s' set up to track remote ref %s.";
> > +			if (!all_shortnames && !origin && rebasing && plural)
> > +				msg_fmt = "Branch '%s' set up to track local refs %s by rebasing.";
> > +			if (!all_shortnames && !origin && rebasing && !plural)
> > +				msg_fmt = "Branch '%s' set up to track local ref %s by rebasing.";
> > +			if (!all_shortnames && !origin && !rebasing && plural)
> > +				msg_fmt = "Branch '%s' set up to track local refs %s.";
> > +			if (!all_shortnames && !origin && !rebasing && !plural)
> > +				msg_fmt = "Branch '%s' set up to track local ref %s.";
> 
> ...in English you've got one dog, then dogs, so == 1 and >1, but in
> various other languages it's:
> 
>     git grep Plural-Forms -- po
> 
> Anyway, this is easily solved, and even with less verbosity, see:
> 
>     git grep -E -W '\bQ_\('
> 
> For examples of how to use the magic of libintl to do this for you.

Thank you for the pointer. I looked specifically for dealing with plural
forms in our docs, but the referenced "Preparing Strings" gettext docs
were not helpful for this. (Although I see now I should have read
further in po/README.md to find the relevant advice).  I may send a
separate change to po/README.md to make it easier to find in the future.

> > +
> > +			printf_ln(_(msg_fmt), local, ref_string);
> 
> ...also s/Branch/branch/ for all of them/.

Done.

> >  		}
> > +
> > +		strbuf_release(&ref_string);
> >  	}
> >  
> >  	return 0;
> > @@ -121,11 +168,18 @@ int install_branch_config(int flag, const char *local, const char *origin, const
> >  	advise(_(tracking_advice),
> >  	       origin ? origin : "",
> >  	       origin ? "/" : "",
> > -	       shortname ? shortname : remote);
> > +	       remotes->items[0].string);
> >  
> >  	return -1;
> >  }
> >  
> > +int install_branch_config(int flag, const char *local, const char *origin, const char *remote) {
> 
> nit: overly long line..

Fixed.

> > +	struct string_list remotes = STRING_LIST_INIT_DUP;
> 
> nit: an extra \n after variable decls...

Fixed.

> > +	string_list_append(&remotes, remote);
> > +	return install_branch_config_multiple_remotes(flag, local, origin, &remotes);
> > +	string_list_clear(&remotes, 0);
> > +}
> > +
> >  /*
> >   * This is called when new_ref is branched off of orig_ref, and tries
> >   * to infer the settings for branch.<new_ref>.{remote,merge} from the
> 

Thanks for the review!