Merge branch 'kn/ref-filter-branch-list'

The code to list branches in "git branch" has been consolidated
with the more generic ref-filter API.

* kn/ref-filter-branch-list: (21 commits)
  ref-filter: resurrect "strip" as a synonym to "lstrip"
  branch: implement '--format' option
  branch: use ref-filter printing APIs
  branch, tag: use porcelain output
  ref-filter: allow porcelain to translate messages in the output
  ref-filter: add an 'rstrip=<N>' option to atoms which deal with refnames
  ref-filter: modify the 'lstrip=<N>' option to work with negative '<N>'
  ref-filter: Do not abruptly die when using the 'lstrip=<N>' option
  ref-filter: rename the 'strip' option to 'lstrip'
  ref-filter: make remote_ref_atom_parser() use refname_atom_parser_internal()
  ref-filter: introduce refname_atom_parser()
  ref-filter: introduce refname_atom_parser_internal()
  ref-filter: make "%(symref)" atom work with the ':short' modifier
  ref-filter: add support for %(upstream:track,nobracket)
  ref-filter: make %(upstream:track) prints "[gone]" for invalid upstreams
  ref-filter: introduce format_ref_array_item()
  ref-filter: move get_head_description() from branch.c
  ref-filter: modify "%(objectname:short)" to take length
  ref-filter: implement %(if:equals=<string>) and %(if:notequals=<string>)
  ref-filter: include reference to 'used_atom' within 'atom_value'
  ...

Documentation/git-branch.txt

@@ -12,7 +12,7 @@ SYNOPSIS
 	[--list] [-v [--abbrev=<length> | --no-abbrev]]
 	[--column[=<options>] | --no-column]
 	[(--merged | --no-merged | --contains) [<commit>]] [--sort=<key>]
-	[--points-at <object>] [<pattern>...]
+	[--points-at <object>] [--format=<format>] [<pattern>...]
 'git branch' [--set-upstream | --track | --no-track] [-l] [-f] <branchname> [<start-point>]
 'git branch' (--set-upstream-to=<upstream> | -u <upstream>) [<branchname>]
 'git branch' --unset-upstream [<branchname>]
@@ -253,6 +253,11 @@ start-point is either a local or remote-tracking branch.
 --points-at <object>::
 	Only list branches of the given object.
 
+--format <format>::
+	A string that interpolates `%(fieldname)` from the object
+	pointed at by a ref being shown.  The format is the same as
+	that of linkgit:git-for-each-ref[1].
+
 Examples
 --------
 

Documentation/git-for-each-ref.txt

@@ -95,11 +95,20 @@ refname::
 	The name of the ref (the part after $GIT_DIR/).
 	For a non-ambiguous short name of the ref append `:short`.
 	The option core.warnAmbiguousRefs is used to select the strict
-	abbreviation mode. If `strip=<N>` is appended, strips `<N>`
-	slash-separated path components from the front of the refname
-	(e.g., `%(refname:strip=2)` turns `refs/tags/foo` into `foo`.
-	`<N>` must be a positive integer.  If a displayed ref has fewer
-	components than `<N>`, the command aborts with an error.
+	abbreviation mode. If `lstrip=<N>` (`rstrip=<N>`) is appended, strips `<N>`
+	slash-separated path components from the front (back) of the refname
+	(e.g. `%(refname:lstrip=2)` turns `refs/tags/foo` into `foo` and
+	`%(refname:rstrip=2)` turns `refs/tags/foo` into `refs`).
+	If `<N>` is a negative number, strip as many path components as
+	necessary from the specified end to leave `-<N>` path components
+	(e.g. `%(refname:lstrip=-2)` turns
+	`refs/tags/foo` into `tags/foo` and `%(refname:rstrip=-1)`
+	turns `refs/tags/foo` into `refs`). When the ref does not have
+	enough components, the result becomes an empty string if
+	stripping with positive <N>, or it becomes the full refname if
+	stripping with negative <N>.  Neither is an error.
++
+`strip` can be used as a synomym to `lstrip`.
 
 objecttype::
 	The type of the object (`blob`, `tree`, `commit`, `tag`).
@@ -110,21 +119,31 @@ objectsize::
 objectname::
 	The object name (aka SHA-1).
 	For a non-ambiguous abbreviation of the object name append `:short`.
+	For an abbreviation of the object name with desired length append
+	`:short=<length>`, where the minimum length is MINIMUM_ABBREV. The
+	length may be exceeded to ensure unique object names.
 
 upstream::
 	The name of a local ref which can be considered ``upstream''
-	from the displayed ref. Respects `:short` in the same way as
-	`refname` above.  Additionally respects `:track` to show
-	"[ahead N, behind M]" and `:trackshort` to show the terse
-	version: ">" (ahead), "<" (behind), "<>" (ahead and behind),
-	or "=" (in sync).  Has no effect if the ref does not have
-	tracking information associated with it.
+	from the displayed ref. Respects `:short`, `:lstrip` and
+	`:rstrip` in the same way as `refname` above.  Additionally
+	respects `:track` to show "[ahead N, behind M]" and
+	`:trackshort` to show the terse version: ">" (ahead), "<"
+	(behind), "<>" (ahead and behind), or "=" (in sync). `:track`
+	also prints "[gone]" whenever unknown upstream ref is
+	encountered. Append `:track,nobracket` to show tracking
+	information without brackets (i.e "ahead N, behind M").  Has
+	no effect if the ref does not have tracking information
+	associated with it.  All the options apart from `nobracket`
+	are mutually exclusive, but if used together the last option
+	is selected.
 
 push::
-	The name of a local ref which represents the `@{push}` location
-	for the displayed ref. Respects `:short`, `:track`, and
-	`:trackshort` options as `upstream` does. Produces an empty
-	string if no `@{push}` ref is configured.
+	The name of a local ref which represents the `@{push}`
+	location for the displayed ref. Respects `:short`, `:lstrip`,
+	`:rstrip`, `:track`, and `:trackshort` options as `upstream`
+	does. Produces an empty string if no `@{push}` ref is
+	configured.
 
 HEAD::
 	'*' if HEAD matches current ref (the checked out branch), ' '
@@ -149,6 +168,25 @@ align::
 	quoted, but if nested then only the topmost level performs
 	quoting.
 
+if::
+	Used as %(if)...%(then)...%(end) or
+	%(if)...%(then)...%(else)...%(end).  If there is an atom with
+	value or string literal after the %(if) then everything after
+	the %(then) is printed, else if the %(else) atom is used, then
+	everything after %(else) is printed. We ignore space when
+	evaluating the string before %(then), this is useful when we
+	use the %(HEAD) atom which prints either "*" or " " and we
+	want to apply the 'if' condition only on the 'HEAD' ref.
+	Append ":equals=<string>" or ":notequals=<string>" to compare
+	the value between the %(if:...) and %(then) atoms with the
+	given string.
+
+symref::
+	The ref which the given symbolic ref refers to. If not a
+	symbolic ref, nothing is printed. Respects the `:short`,
+	`:lstrip` and `:rstrip` options in the same way as `refname`
+	above.
+
 In addition to the above, for commit and tag objects, the header
 field names (`tree`, `parent`, `object`, `type`, and `tag`) can
 be used to specify the value in the header field.
@@ -186,6 +224,14 @@ As a special case for the date-type fields, you may specify a format for
 the date by adding `:` followed by date format name (see the
 values the `--date` option to linkgit:git-rev-list[1] takes).
 
+Some atoms like %(align) and %(if) always require a matching %(end).
+We call them "opening atoms" and sometimes denote them as %($open).
+
+When a scripting language specific quoting is in effect, everything
+between a top-level opening atom and its matching %(end) is evaluated
+according to the semantics of the opening atom and only its result
+from the top-level is quoted.
+
 
 EXAMPLES
 --------
@@ -273,6 +319,22 @@ eval=`git for-each-ref --shell --format="$fmt" \
 eval "$eval"
 ------------
 
+
+An example to show the usage of %(if)...%(then)...%(else)...%(end).
+This prefixes the current branch with a star.
+
+------------
+git for-each-ref --format="%(if)%(HEAD)%(then)* %(else)  %(end)%(refname:short)" refs/heads/
+------------
+
+
+An example to show the usage of %(if)...%(then)...%(end).
+This prints the authorname, if present.
+
+------------
+git for-each-ref --format="%(refname)%(if)%(authorname)%(then) Authored by: %(authorname)%(end)"
+------------
+
 SEE ALSO
 --------
 linkgit:git-show-ref[1]

builtin/branch.c

@@ -28,6 +28,7 @@ static const char * const builtin_branch_usage[] = {
 	N_("git branch [<options>] [-r] (-d | -D) <branch-name>..."),
 	N_("git branch [<options>] (-m | -M) [<old-branch>] <new-branch>"),
 	N_("git branch [<options>] [-r | -a] [--points-at]"),
+	N_("git branch [<options>] [-r | -a] [--format]"),
 	NULL
 };
 
@@ -37,11 +38,11 @@ static unsigned char head_sha1[20];
 static int branch_use_color = -1;
 static char branch_colors[][COLOR_MAXLEN] = {
 	GIT_COLOR_RESET,
-	GIT_COLOR_NORMAL,	/* PLAIN */
-	GIT_COLOR_RED,		/* REMOTE */
-	GIT_COLOR_NORMAL,	/* LOCAL */
-	GIT_COLOR_GREEN,	/* CURRENT */
-	GIT_COLOR_BLUE,		/* UPSTREAM */
+	GIT_COLOR_NORMAL,       /* PLAIN */
+	GIT_COLOR_RED,          /* REMOTE */
+	GIT_COLOR_NORMAL,       /* LOCAL */
+	GIT_COLOR_GREEN,        /* CURRENT */
+	GIT_COLOR_BLUE,         /* UPSTREAM */
 };
 enum color_branch {
 	BRANCH_COLOR_RESET = 0,
@@ -280,221 +281,98 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 	return(ret);
 }
 
-static void fill_tracking_info(struct strbuf *stat, const char *branch_name,
-		int show_upstream_ref)
+static int calc_maxwidth(struct ref_array *refs, int remote_bonus)
 {
-	int ours, theirs;
-	char *ref = NULL;
-	struct branch *branch = branch_get(branch_name);
-	const char *upstream;
-	struct strbuf fancy = STRBUF_INIT;
-	int upstream_is_gone = 0;
-	int added_decoration = 1;
-
-	if (stat_tracking_info(branch, &ours, &theirs, &upstream) < 0) {
-		if (!upstream)
-			return;
-		upstream_is_gone = 1;
-	}
-
-	if (show_upstream_ref) {
-		ref = shorten_unambiguous_ref(upstream, 0);
-		if (want_color(branch_use_color))
-			strbuf_addf(&fancy, "%s%s%s",
-					branch_get_color(BRANCH_COLOR_UPSTREAM),
-					ref, branch_get_color(BRANCH_COLOR_RESET));
-		else
-			strbuf_addstr(&fancy, ref);
-	}
+	int i, max = 0;
+	for (i = 0; i < refs->nr; i++) {
+		struct ref_array_item *it = refs->items[i];
+		const char *desc = it->refname;
+		int w;
 
-	if (upstream_is_gone) {
-		if (show_upstream_ref)
-			strbuf_addf(stat, _("[%s: gone]"), fancy.buf);
-		else
-			added_decoration = 0;
-	} else if (!ours && !theirs) {
-		if (show_upstream_ref)
-			strbuf_addf(stat, _("[%s]"), fancy.buf);
-		else
-			added_decoration = 0;
-	} else if (!ours) {
-		if (show_upstream_ref)
-			strbuf_addf(stat, _("[%s: behind %d]"), fancy.buf, theirs);
-		else
-			strbuf_addf(stat, _("[behind %d]"), theirs);
+		skip_prefix(it->refname, "refs/heads/", &desc);
+		skip_prefix(it->refname, "refs/remotes/", &desc);
+		if (it->kind == FILTER_REFS_DETACHED_HEAD) {
+			char *head_desc = get_head_description();
+			w = utf8_strwidth(head_desc);
+			free(head_desc);
+		} else
+			w = utf8_strwidth(desc);
 
-	} else if (!theirs) {
-		if (show_upstream_ref)
-			strbuf_addf(stat, _("[%s: ahead %d]"), fancy.buf, ours);
-		else
-			strbuf_addf(stat, _("[ahead %d]"), ours);
-	} else {
-		if (show_upstream_ref)
-			strbuf_addf(stat, _("[%s: ahead %d, behind %d]"),
-				    fancy.buf, ours, theirs);
-		else
-			strbuf_addf(stat, _("[ahead %d, behind %d]"),
-				    ours, theirs);
+		if (it->kind == FILTER_REFS_REMOTES)
+			w += remote_bonus;
+		if (w > max)
+			max = w;
 	}
-	strbuf_release(&fancy);
-	if (added_decoration)
-		strbuf_addch(stat, ' ');
-	free(ref);
+	return max;
 }
 
-static void add_verbose_info(struct strbuf *out, struct ref_array_item *item,
-			     struct ref_filter *filter, const char *refname)
+static const char *quote_literal_for_format(const char *s)
 {
-	struct strbuf subject = STRBUF_INIT, stat = STRBUF_INIT;
-	const char *sub = _(" **** invalid ref ****");
-	struct commit *commit = item->commit;
+	static struct strbuf buf = STRBUF_INIT;
 
-	if (!parse_commit(commit)) {
-		pp_commit_easy(CMIT_FMT_ONELINE, commit, &subject);
-		sub = subject.buf;
+	strbuf_reset(&buf);
+	while (*s) {
+		const char *ep = strchrnul(s, '%');
+		if (s < ep)
+			strbuf_add(&buf, s, ep - s);
+		if (*ep == '%') {
+			strbuf_addstr(&buf, "%%");
+			s = ep + 1;
+		} else {
+			s = ep;
+		}
 	}
-
-	if (item->kind == FILTER_REFS_BRANCHES)
-		fill_tracking_info(&stat, refname, filter->verbose > 1);
-
-	strbuf_addf(out, " %s %s%s",
-		find_unique_abbrev(item->commit->object.oid.hash, filter->abbrev),
-		stat.buf, sub);
-	strbuf_release(&stat);
-	strbuf_release(&subject);
+	return buf.buf;
 }
 
-static char *get_head_description(void)
+static char *build_format(struct ref_filter *filter, int maxwidth, const char *remote_prefix)
 {
-	struct strbuf desc = STRBUF_INIT;
-	struct wt_status_state state;
-	memset(&state, 0, sizeof(state));
-	wt_status_get_state(&state, 1);
-	if (state.rebase_in_progress ||
-	    state.rebase_interactive_in_progress)
-		strbuf_addf(&desc, _("(no branch, rebasing %s)"),
-			    state.branch);
-	else if (state.bisect_in_progress)
-		strbuf_addf(&desc, _("(no branch, bisect started on %s)"),
-			    state.branch);
-	else if (state.detached_from) {
-		if (state.detached_at)
-			/* TRANSLATORS: make sure this matches
-			   "HEAD detached at " in wt-status.c */
-			strbuf_addf(&desc, _("(HEAD detached at %s)"),
-				state.detached_from);
-		else
-			/* TRANSLATORS: make sure this matches
-			   "HEAD detached from " in wt-status.c */
-			strbuf_addf(&desc, _("(HEAD detached from %s)"),
-				state.detached_from);
-	}
-	else
-		strbuf_addstr(&desc, _("(no branch)"));
-	free(state.branch);
-	free(state.onto);
-	free(state.detached_from);
-	return strbuf_detach(&desc, NULL);
-}
+	struct strbuf fmt = STRBUF_INIT;
+	struct strbuf local = STRBUF_INIT;
+	struct strbuf remote = STRBUF_INIT;
 
-static void format_and_print_ref_item(struct ref_array_item *item, int maxwidth,
-				      struct ref_filter *filter, const char *remote_prefix)
-{
-	char c;
-	int current = 0;
-	int color;
-	struct strbuf out = STRBUF_INIT, name = STRBUF_INIT;
-	const char *prefix_to_show = "";
-	const char *prefix_to_skip = NULL;
-	const char *desc = item->refname;
-	char *to_free = NULL;
+	strbuf_addf(&fmt, "%%(if)%%(HEAD)%%(then)* %s%%(else)  %%(end)",
+		    branch_get_color(BRANCH_COLOR_CURRENT));
 
-	switch (item->kind) {
-	case FILTER_REFS_BRANCHES:
-		prefix_to_skip = "refs/heads/";
-		skip_prefix(desc, prefix_to_skip, &desc);
-		if (!filter->detached && !strcmp(desc, head))
-			current = 1;
+	if (filter->verbose) {
+		strbuf_addf(&local, "%%(align:%d,left)%%(refname:lstrip=2)%%(end)", maxwidth);
+		strbuf_addf(&local, "%s", branch_get_color(BRANCH_COLOR_RESET));
+		strbuf_addf(&local, " %%(objectname:short=7) ");
+
+		if (filter->verbose > 1)
+			strbuf_addf(&local, "%%(if)%%(upstream)%%(then)[%s%%(upstream:short)%s%%(if)%%(upstream:track)"
+				    "%%(then): %%(upstream:track,nobracket)%%(end)] %%(end)%%(contents:subject)",
+				    branch_get_color(BRANCH_COLOR_UPSTREAM), branch_get_color(BRANCH_COLOR_RESET));
 		else
-			color = BRANCH_COLOR_LOCAL;
-		break;
-	case FILTER_REFS_REMOTES:
-		prefix_to_skip = "refs/remotes/";
-		skip_prefix(desc, prefix_to_skip, &desc);
-		color = BRANCH_COLOR_REMOTE;
-		prefix_to_show = remote_prefix;
-		break;
-	case FILTER_REFS_DETACHED_HEAD:
-		desc = to_free = get_head_description();
-		current = 1;
-		break;
-	default:
-		color = BRANCH_COLOR_PLAIN;
-		break;
-	}
+			strbuf_addf(&local, "%%(if)%%(upstream:track)%%(then)%%(upstream:track) %%(end)%%(contents:subject)");
 
-	c = ' ';
-	if (current) {
-		c = '*';
-		color = BRANCH_COLOR_CURRENT;
-	}
-
-	strbuf_addf(&name, "%s%s", prefix_to_show, desc);
-	if (filter->verbose) {
-		int utf8_compensation = strlen(name.buf) - utf8_strwidth(name.buf);
-		strbuf_addf(&out, "%c %s%-*s%s", c, branch_get_color(color),
-			    maxwidth + utf8_compensation, name.buf,
+		strbuf_addf(&remote, "%s%%(align:%d,left)%s%%(refname:lstrip=2)%%(end)%s%%(if)%%(symref)%%(then) -> %%(symref:short)"
+			    "%%(else) %%(objectname:short=7) %%(contents:subject)%%(end)",
+			    branch_get_color(BRANCH_COLOR_REMOTE), maxwidth, quote_literal_for_format(remote_prefix),
 			    branch_get_color(BRANCH_COLOR_RESET));
-	} else
-		strbuf_addf(&out, "%c %s%s%s", c, branch_get_color(color),
-			    name.buf, branch_get_color(BRANCH_COLOR_RESET));
-
-	if (item->symref) {
-		const char *symref = item->symref;
-		if (prefix_to_skip)
-			skip_prefix(symref, prefix_to_skip, &symref);
-		strbuf_addf(&out, " -> %s", symref);
-	}
-	else if (filter->verbose)
-		/* " f7c0c00 [ahead 58, behind 197] vcs-svn: drop obj_pool.h" */
-		add_verbose_info(&out, item, filter, desc);
-	if (column_active(colopts)) {
-		assert(!filter->verbose && "--column and --verbose are incompatible");
-		string_list_append(&output, out.buf);
 	} else {
-		printf("%s\n", out.buf);
+		strbuf_addf(&local, "%%(refname:lstrip=2)%s%%(if)%%(symref)%%(then) -> %%(symref:short)%%(end)",
+			    branch_get_color(BRANCH_COLOR_RESET));
+		strbuf_addf(&remote, "%s%s%%(refname:lstrip=2)%s%%(if)%%(symref)%%(then) -> %%(symref:short)%%(end)",
+			    branch_get_color(BRANCH_COLOR_REMOTE), quote_literal_for_format(remote_prefix),
+			    branch_get_color(BRANCH_COLOR_RESET));
 	}
-	strbuf_release(&name);
-	strbuf_release(&out);
-	free(to_free);
-}
-
-static int calc_maxwidth(struct ref_array *refs, int remote_bonus)
-{
-	int i, max = 0;
-	for (i = 0; i < refs->nr; i++) {
-		struct ref_array_item *it = refs->items[i];
-		const char *desc = it->refname;
-		int w;
 
-		skip_prefix(it->refname, "refs/heads/", &desc);
-		skip_prefix(it->refname, "refs/remotes/", &desc);
-		w = utf8_strwidth(desc);
+	strbuf_addf(&fmt, "%%(if:notequals=refs/remotes)%%(refname:rstrip=-2)%%(then)%s%%(else)%s%%(end)", local.buf, remote.buf);
 
-		if (it->kind == FILTER_REFS_REMOTES)
-			w += remote_bonus;
-		if (w > max)
-			max = w;
-	}
-	return max;
+	strbuf_release(&local);
+	strbuf_release(&remote);
+	return strbuf_detach(&fmt, NULL);
 }
 
-static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sorting)
+static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sorting, const char *format)
 {
 	int i;
 	struct ref_array array;
 	int maxwidth = 0;
 	const char *remote_prefix = "";
+	struct strbuf out = STRBUF_INIT;
+	char *to_free = NULL;
 
 	/*
 	 * If we are listing more than just remote branches,
@@ -506,18 +384,32 @@ static void print_ref_list(struct ref_filter *filter, struct ref_sorting *sortin
 
 	memset(&array, 0, sizeof(array));
 
-	verify_ref_format("%(refname)%(symref)");
 	filter_refs(&array, filter, filter->kind | FILTER_REFS_INCLUDE_BROKEN);
 
 	if (filter->verbose)
 		maxwidth = calc_maxwidth(&array, strlen(remote_prefix));
 
+	if (!format)
+		format = to_free = build_format(filter, maxwidth, remote_prefix);
+	verify_ref_format(format);
+
 	ref_array_sort(sorting, &array);
 
-	for (i = 0; i < array.nr; i++)
-		format_and_print_ref_item(array.items[i], maxwidth, filter, remote_prefix);
+	for (i = 0; i < array.nr; i++) {
+		format_ref_array_item(array.items[i], format, 0, &out);
+		if (column_active(colopts)) {
+			assert(!filter->verbose && "--column and --verbose are incompatible");
+			 /* format to a string_list to let print_columns() do its job */
+			string_list_append(&output, out.buf);
+		} else {
+			fwrite(out.buf, 1, out.len, stdout);
+			putchar('\n');
+		}
+		strbuf_release(&out);
+	}
 
 	ref_array_clear(&array);
+	free(to_free);
 }
 
 static void reject_rebase_or_bisect_branch(const char *target)
@@ -638,6 +530,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 	struct ref_filter filter;
 	int icase = 0;
 	static struct ref_sorting *sorting = NULL, **sorting_tail = &sorting;
+	const char *format = NULL;
 
 	struct option options[] = {
 		OPT_GROUP(N_("Generic options")),
@@ -679,9 +572,12 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 			N_("print only branches of the object"), 0, parse_opt_object_name
 		},
 		OPT_BOOL('i', "ignore-case", &icase, N_("sorting and filtering are case insensitive")),
+		OPT_STRING(  0 , "format", &format, N_("format"), N_("format to use for the output")),
 		OPT_END(),
 	};
 
+	setup_ref_filter_porcelain_msg();
+
 	memset(&filter, 0, sizeof(filter));
 	filter.kind = FILTER_REFS_BRANCHES;
 	filter.abbrev = -1;
@@ -749,7 +645,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 		if (!sorting)
 			sorting = ref_default_sorting();
 		sorting->ignore_case = icase;
-		print_ref_list(&filter, sorting);
+		print_ref_list(&filter, sorting, format);
 		print_columns(&output, colopts, NULL);
 		string_list_clear(&output, 0);
 		return 0;

builtin/tag.c

@@ -45,11 +45,11 @@ static int list_tags(struct ref_filter *filter, struct ref_sorting *sorting, con
 	if (!format) {
 		if (filter->lines) {
 			to_free = xstrfmt("%s %%(contents:lines=%d)",
-					  "%(align:15)%(refname:strip=2)%(end)",
+					  "%(align:15)%(refname:lstrip=2)%(end)",
 					  filter->lines);
 			format = to_free;
 		} else
-			format = "%(refname:strip=2)";
+			format = "%(refname:lstrip=2)";
 	}
 
 	verify_ref_format(format);
@@ -389,6 +389,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
+	setup_ref_filter_porcelain_msg();
+
 	git_config(git_tag_config, sorting_tail);
 
 	memset(&opt, 0, sizeof(opt));

ref-filter.c

@@ -14,14 +14,50 @@
 #include "git-compat-util.h"
 #include "version.h"
 #include "trailer.h"
+#include "wt-status.h"
+
+static struct ref_msg {
+	const char *gone;
+	const char *ahead;
+	const char *behind;
+	const char *ahead_behind;
+} msgs = {
+	 /* Untranslated plumbing messages: */
+	"gone",
+	"ahead %d",
+	"behind %d",
+	"ahead %d, behind %d"
+};
+
+void setup_ref_filter_porcelain_msg(void)
+{
+	msgs.gone = _("gone");
+	msgs.ahead = _("ahead %d");
+	msgs.behind = _("behind %d");
+	msgs.ahead_behind = _("ahead %d, behind %d");
+}
 
 typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME } cmp_type;
+typedef enum { COMPARE_EQUAL, COMPARE_UNEQUAL, COMPARE_NONE } cmp_status;
 
 struct align {
 	align_type position;
 	unsigned int width;
 };
 
+struct if_then_else {
+	cmp_status cmp_status;
+	const char *str;
+	unsigned int then_atom_seen : 1,
+		else_atom_seen : 1,
+		condition_satisfied : 1;
+};
+
+struct refname_atom {
+	enum { R_NORMAL, R_SHORT, R_LSTRIP, R_RSTRIP } option;
+	int lstrip, rstrip;
+};
+
 /*
  * An atom is a valid field atom listed below, possibly prefixed with
  * a "*" to denote deref_tag().
@@ -38,13 +74,24 @@ static struct used_atom {
 	union {
 		char color[COLOR_MAXLEN];
 		struct align align;
-		enum { RR_NORMAL, RR_SHORTEN, RR_TRACK, RR_TRACKSHORT }
-			remote_ref;
+		struct {
+			enum { RR_REF, RR_TRACK, RR_TRACKSHORT } option;
+			struct refname_atom refname;
+			unsigned int nobracket : 1;
+		} remote_ref;
 		struct {
 			enum { C_BARE, C_BODY, C_BODY_DEP, C_LINES, C_SIG, C_SUB, C_TRAILERS } option;
 			unsigned int nlines;
 		} contents;
-		enum { O_FULL, O_SHORT } objectname;
+		struct {
+			cmp_status cmp_status;
+			const char *str;
+		} if_then_else;
+		struct {
+			enum { O_FULL, O_LENGTH, O_SHORT } option;
+			unsigned int length;
+		} objectname;
+		struct refname_atom refname;
 	} u;
 } *used_atom;
 static int used_atom_cnt, need_tagged, need_symref;
@@ -58,18 +105,58 @@ static void color_atom_parser(struct used_atom *atom, const char *color_value)
 		die(_("unrecognized color: %%(color:%s)"), color_value);
 }
 
-static void remote_ref_atom_parser(struct used_atom *atom, const char *arg)
+static void refname_atom_parser_internal(struct refname_atom *atom,
+					 const char *arg, const char *name)
 {
 	if (!arg)
-		atom->u.remote_ref = RR_NORMAL;
+		atom->option = R_NORMAL;
 	else if (!strcmp(arg, "short"))
-		atom->u.remote_ref = RR_SHORTEN;
-	else if (!strcmp(arg, "track"))
-		atom->u.remote_ref = RR_TRACK;
-	else if (!strcmp(arg, "trackshort"))
-		atom->u.remote_ref = RR_TRACKSHORT;
-	else
-		die(_("unrecognized format: %%(%s)"), atom->name);
+		atom->option = R_SHORT;
+	else if (skip_prefix(arg, "lstrip=", &arg) ||
+		 skip_prefix(arg, "strip=", &arg)) {
+		atom->option = R_LSTRIP;
+		if (strtol_i(arg, 10, &atom->lstrip))
+			die(_("Integer value expected refname:lstrip=%s"), arg);
+	} else if (skip_prefix(arg, "rstrip=", &arg)) {
+		atom->option = R_RSTRIP;
+		if (strtol_i(arg, 10, &atom->rstrip))
+			die(_("Integer value expected refname:rstrip=%s"), arg);
+	} else
+		die(_("unrecognized %%(%s) argument: %s"), name, arg);
+}
+
+static void remote_ref_atom_parser(struct used_atom *atom, const char *arg)
+{
+	struct string_list params = STRING_LIST_INIT_DUP;
+	int i;
+
+	if (!arg) {
+		atom->u.remote_ref.option = RR_REF;
+		refname_atom_parser_internal(&atom->u.remote_ref.refname,
+					     arg, atom->name);
+		return;
+	}
+
+	atom->u.remote_ref.nobracket = 0;
+	string_list_split(&params, arg, ',', -1);
+
+	for (i = 0; i < params.nr; i++) {
+		const char *s = params.items[i].string;
+
+		if (!strcmp(s, "track"))
+			atom->u.remote_ref.option = RR_TRACK;
+		else if (!strcmp(s, "trackshort"))
+			atom->u.remote_ref.option = RR_TRACKSHORT;
+		else if (!strcmp(s, "nobracket"))
+			atom->u.remote_ref.nobracket = 1;
+		else {
+			atom->u.remote_ref.option = RR_REF;
+			refname_atom_parser_internal(&atom->u.remote_ref.refname,
+						     arg, atom->name);
+		}
+	}
+
+	string_list_clear(&params, 0);
 }
 
 static void body_atom_parser(struct used_atom *atom, const char *arg)
@@ -116,13 +203,25 @@ static void contents_atom_parser(struct used_atom *atom, const char *arg)
 static void objectname_atom_parser(struct used_atom *atom, const char *arg)
 {
 	if (!arg)
-		atom->u.objectname = O_FULL;
+		atom->u.objectname.option = O_FULL;
 	else if (!strcmp(arg, "short"))
-		atom->u.objectname = O_SHORT;
-	else
+		atom->u.objectname.option = O_SHORT;
+	else if (skip_prefix(arg, "short=", &arg)) {
+		atom->u.objectname.option = O_LENGTH;
+		if (strtoul_ui(arg, 10, &atom->u.objectname.length) ||
+		    atom->u.objectname.length == 0)
+			die(_("positive value expected objectname:short=%s"), arg);
+		if (atom->u.objectname.length < MINIMUM_ABBREV)
+			atom->u.objectname.length = MINIMUM_ABBREV;
+	} else
 		die(_("unrecognized %%(objectname) argument: %s"), arg);
 }
 
+static void refname_atom_parser(struct used_atom *atom, const char *arg)
+{
+	return refname_atom_parser_internal(&atom->u.refname, arg, atom->name);
+}
+
 static align_type parse_align_position(const char *s)
 {
 	if (!strcmp(s, "right"))
@@ -173,12 +272,27 @@ static void align_atom_parser(struct used_atom *atom, const char *arg)
 	string_list_clear(&params, 0);
 }
 
+static void if_atom_parser(struct used_atom *atom, const char *arg)
+{
+	if (!arg) {
+		atom->u.if_then_else.cmp_status = COMPARE_NONE;
+		return;
+	} else if (skip_prefix(arg, "equals=", &atom->u.if_then_else.str)) {
+		atom->u.if_then_else.cmp_status = COMPARE_EQUAL;
+	} else if (skip_prefix(arg, "notequals=", &atom->u.if_then_else.str)) {
+		atom->u.if_then_else.cmp_status = COMPARE_UNEQUAL;
+	} else {
+		die(_("unrecognized %%(if) argument: %s"), arg);
+	}
+}
+
+
 static struct {
 	const char *name;
 	cmp_type cmp_type;
 	void (*parser)(struct used_atom *atom, const char *arg);
 } valid_atom[] = {
-	{ "refname" },
+	{ "refname" , FIELD_STR, refname_atom_parser },
 	{ "objecttype" },
 	{ "objectsize", FIELD_ULONG },
 	{ "objectname", FIELD_STR, objectname_atom_parser },
@@ -208,12 +322,15 @@ static struct {
 	{ "contents", FIELD_STR, contents_atom_parser },
 	{ "upstream", FIELD_STR, remote_ref_atom_parser },
 	{ "push", FIELD_STR, remote_ref_atom_parser },
-	{ "symref" },
+	{ "symref", FIELD_STR, refname_atom_parser },
 	{ "flag" },
 	{ "HEAD" },
 	{ "color", FIELD_STR, color_atom_parser },
 	{ "align", FIELD_STR, align_atom_parser },
 	{ "end" },
+	{ "if", FIELD_STR, if_atom_parser },
+	{ "then" },
+	{ "else" },
 };
 
 #define REF_FORMATTING_STATE_INIT  { 0, NULL }
@@ -221,7 +338,7 @@ static struct {
 struct ref_formatting_stack {
 	struct ref_formatting_stack *prev;
 	struct strbuf output;
-	void (*at_end)(struct ref_formatting_stack *stack);
+	void (*at_end)(struct ref_formatting_stack **stack);
 	void *at_end_data;
 };
 
@@ -232,11 +349,9 @@ struct ref_formatting_state {
 
 struct atom_value {
 	const char *s;
-	union {
-		struct align align;
-	} u;
 	void (*handler)(struct atom_value *atomv, struct ref_formatting_state *state);
 	unsigned long ul; /* used for sorting when not FIELD_STR */
+	struct used_atom *atom;
 };
 
 /*
@@ -293,7 +408,7 @@ int parse_ref_filter_atom(const char *atom, const char *ep)
 		valid_atom[i].parser(&used_atom[at], arg);
 	if (*atom == '*')
 		need_tagged = 1;
-	if (!strcmp(used_atom[at].name, "symref"))
+	if (!strcmp(valid_atom[i].name, "symref"))
 		need_symref = 1;
 	return at;
 }
@@ -354,13 +469,14 @@ static void pop_stack_element(struct ref_formatting_stack **stack)
 	*stack = prev;
 }
 
-static void end_align_handler(struct ref_formatting_stack *stack)
+static void end_align_handler(struct ref_formatting_stack **stack)
 {
-	struct align *align = (struct align *)stack->at_end_data;
+	struct ref_formatting_stack *cur = *stack;
+	struct align *align = (struct align *)cur->at_end_data;
 	struct strbuf s = STRBUF_INIT;
 
-	strbuf_utf8_align(&s, align->position, align->width, stack->output.buf);
-	strbuf_swap(&stack->output, &s);
+	strbuf_utf8_align(&s, align->position, align->width, cur->output.buf);
+	strbuf_swap(&cur->output, &s);
 	strbuf_release(&s);
 }
 
@@ -371,7 +487,115 @@ static void align_atom_handler(struct atom_value *atomv, struct ref_formatting_s
 	push_stack_element(&state->stack);
 	new = state->stack;
 	new->at_end = end_align_handler;
-	new->at_end_data = &atomv->u.align;
+	new->at_end_data = &atomv->atom->u.align;
+}
+
+static void if_then_else_handler(struct ref_formatting_stack **stack)
+{
+	struct ref_formatting_stack *cur = *stack;
+	struct ref_formatting_stack *prev = cur->prev;
+	struct if_then_else *if_then_else = (struct if_then_else *)cur->at_end_data;
+
+	if (!if_then_else->then_atom_seen)
+		die(_("format: %%(if) atom used without a %%(then) atom"));
+
+	if (if_then_else->else_atom_seen) {
+		/*
+		 * There is an %(else) atom: we need to drop one state from the
+		 * stack, either the %(else) branch if the condition is satisfied, or
+		 * the %(then) branch if it isn't.
+		 */
+		if (if_then_else->condition_satisfied) {
+			strbuf_reset(&cur->output);
+			pop_stack_element(&cur);
+		} else {
+			strbuf_swap(&cur->output, &prev->output);
+			strbuf_reset(&cur->output);
+			pop_stack_element(&cur);
+		}
+	} else if (!if_then_else->condition_satisfied) {
+		/*
+		 * No %(else) atom: just drop the %(then) branch if the
+		 * condition is not satisfied.
+		 */
+		strbuf_reset(&cur->output);
+	}
+
+	*stack = cur;
+	free(if_then_else);
+}
+
+static void if_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
+{
+	struct ref_formatting_stack *new;
+	struct if_then_else *if_then_else = xcalloc(sizeof(struct if_then_else), 1);
+
+	if_then_else->str = atomv->atom->u.if_then_else.str;
+	if_then_else->cmp_status = atomv->atom->u.if_then_else.cmp_status;
+
+	push_stack_element(&state->stack);
+	new = state->stack;
+	new->at_end = if_then_else_handler;
+	new->at_end_data = if_then_else;
+}
+
+static int is_empty(const char *s)
+{
+	while (*s != '\0') {
+		if (!isspace(*s))
+			return 0;
+		s++;
+	}
+	return 1;
+}
+
+static void then_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
+{
+	struct ref_formatting_stack *cur = state->stack;
+	struct if_then_else *if_then_else = NULL;
+
+	if (cur->at_end == if_then_else_handler)
+		if_then_else = (struct if_then_else *)cur->at_end_data;
+	if (!if_then_else)
+		die(_("format: %%(then) atom used without an %%(if) atom"));
+	if (if_then_else->then_atom_seen)
+		die(_("format: %%(then) atom used more than once"));
+	if (if_then_else->else_atom_seen)
+		die(_("format: %%(then) atom used after %%(else)"));
+	if_then_else->then_atom_seen = 1;
+	/*
+	 * If the 'equals' or 'notequals' attribute is used then
+	 * perform the required comparison. If not, only non-empty
+	 * strings satisfy the 'if' condition.
+	 */
+	if (if_then_else->cmp_status == COMPARE_EQUAL) {
+		if (!strcmp(if_then_else->str, cur->output.buf))
+			if_then_else->condition_satisfied = 1;
+	} else if (if_then_else->cmp_status == COMPARE_UNEQUAL) {
+		if (strcmp(if_then_else->str, cur->output.buf))
+			if_then_else->condition_satisfied = 1;
+	} else if (cur->output.len && !is_empty(cur->output.buf))
+		if_then_else->condition_satisfied = 1;
+	strbuf_reset(&cur->output);
+}
+
+static void else_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
+{
+	struct ref_formatting_stack *prev = state->stack;
+	struct if_then_else *if_then_else = NULL;
+
+	if (prev->at_end == if_then_else_handler)
+		if_then_else = (struct if_then_else *)prev->at_end_data;
+	if (!if_then_else)
+		die(_("format: %%(else) atom used without an %%(if) atom"));
+	if (!if_then_else->then_atom_seen)
+		die(_("format: %%(else) atom used without a %%(then) atom"));
+	if (if_then_else->else_atom_seen)
+		die(_("format: %%(else) atom used more than once"));
+	if_then_else->else_atom_seen = 1;
+	push_stack_element(&state->stack);
+	state->stack->at_end_data = prev->at_end_data;
+	state->stack->at_end = prev->at_end;
 }
 
 static void end_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state)
@@ -381,14 +605,17 @@ static void end_atom_handler(struct atom_value *atomv, struct ref_formatting_sta
 
 	if (!current->at_end)
 		die(_("format: %%(end) atom used without corresponding atom"));
-	current->at_end(current);
+	current->at_end(&state->stack);
+
+	/*  Stack may have been popped within at_end(), hence reset the current pointer */
+	current = state->stack;
 
 	/*
 	 * Perform quote formatting when the stack element is that of
 	 * a supporting atom. If nested then perform quote formatting
 	 * only on the topmost supporting atom.
 	 */
-	if (!state->stack->prev->prev) {
+	if (!current->prev->prev) {
 		quote_formatting(&s, current->output.buf, state->quote_style);
 		strbuf_swap(&current->output, &s);
 	}
@@ -465,12 +692,15 @@ static int grab_objectname(const char *name, const unsigned char *sha1,
 			   struct atom_value *v, struct used_atom *atom)
 {
 	if (starts_with(name, "objectname")) {
-		if (atom->u.objectname == O_SHORT) {
+		if (atom->u.objectname.option == O_SHORT) {
 			v->s = xstrdup(find_unique_abbrev(sha1, DEFAULT_ABBREV));
 			return 1;
-		} else if (atom->u.objectname == O_FULL) {
+		} else if (atom->u.objectname.option == O_FULL) {
 			v->s = xstrdup(sha1_to_hex(sha1));
 			return 1;
+		} else if (atom->u.objectname.option == O_LENGTH) {
+			v->s = xstrdup(find_unique_abbrev(sha1, atom->u.objectname.length));
+			return 1;
 		} else
 			die("BUG: unknown %%(objectname) option");
 	}
@@ -887,50 +1117,108 @@ static inline char *copy_advance(char *dst, const char *src)
 	return dst;
 }
 
-static const char *strip_ref_components(const char *refname, const char *nr_arg)
+static const char *lstrip_ref_components(const char *refname, int len)
 {
-	char *end;
-	long nr = strtol(nr_arg, &end, 10);
-	long remaining = nr;
+	long remaining = len;
 	const char *start = refname;
 
-	if (nr < 1 || *end != '\0')
-		die(_(":strip= requires a positive integer argument"));
+	if (len < 0) {
+		int i;
+		const char *p = refname;
+
+		/* Find total no of '/' separated path-components */
+		for (i = 0; p[i]; p[i] == '/' ? i++ : *p++)
+			;
+		/*
+		 * The number of components we need to strip is now
+		 * the total minus the components to be left (Plus one
+		 * because we count the number of '/', but the number
+		 * of components is one more than the no of '/').
+		 */
+		remaining = i + len + 1;
+	}
 
-	while (remaining) {
+	while (remaining > 0) {
 		switch (*start++) {
 		case '\0':
-			die(_("ref '%s' does not have %ld components to :strip"),
-			    refname, nr);
+			return "";
 		case '/':
 			remaining--;
 			break;
 		}
 	}
+
 	return start;
 }
 
+static const char *rstrip_ref_components(const char *refname, int len)
+{
+	long remaining = len;
+	char *start = xstrdup(refname);
+
+	if (len < 0) {
+		int i;
+		const char *p = refname;
+
+		/* Find total no of '/' separated path-components */
+		for (i = 0; p[i]; p[i] == '/' ? i++ : *p++)
+			;
+		/*
+		 * The number of components we need to strip is now
+		 * the total minus the components to be left (Plus one
+		 * because we count the number of '/', but the number
+		 * of components is one more than the no of '/').
+		 */
+		remaining = i + len + 1;
+	}
+
+	while (remaining-- > 0) {
+		char *p = strrchr(start, '/');
+		if (p == NULL)
+			return "";
+		else
+			p[0] = '\0';
+	}
+	return start;
+}
+
+static const char *show_ref(struct refname_atom *atom, const char *refname)
+{
+	if (atom->option == R_SHORT)
+		return shorten_unambiguous_ref(refname, warn_ambiguous_refs);
+	else if (atom->option == R_LSTRIP)
+		return lstrip_ref_components(refname, atom->lstrip);
+	else if (atom->option == R_RSTRIP)
+		return rstrip_ref_components(refname, atom->rstrip);
+	else
+		return refname;
+}
+
 static void fill_remote_ref_details(struct used_atom *atom, const char *refname,
 				    struct branch *branch, const char **s)
 {
 	int num_ours, num_theirs;
-	if (atom->u.remote_ref == RR_SHORTEN)
-		*s = shorten_unambiguous_ref(refname, warn_ambiguous_refs);
-	else if (atom->u.remote_ref == RR_TRACK) {
+	if (atom->u.remote_ref.option == RR_REF)
+		*s = show_ref(&atom->u.remote_ref.refname, refname);
+	else if (atom->u.remote_ref.option == RR_TRACK) {
 		if (stat_tracking_info(branch, &num_ours,
-				       &num_theirs, NULL))
-			return;
-
-		if (!num_ours && !num_theirs)
+				       &num_theirs, NULL)) {
+			*s = xstrdup(msgs.gone);
+		} else if (!num_ours && !num_theirs)
 			*s = "";
 		else if (!num_ours)
-			*s = xstrfmt("[behind %d]", num_theirs);
+			*s = xstrfmt(msgs.behind, num_theirs);
 		else if (!num_theirs)
-			*s = xstrfmt("[ahead %d]", num_ours);
+			*s = xstrfmt(msgs.ahead, num_ours);
 		else
-			*s = xstrfmt("[ahead %d, behind %d]",
+			*s = xstrfmt(msgs.ahead_behind,
 				     num_ours, num_theirs);
-	} else if (atom->u.remote_ref == RR_TRACKSHORT) {
+		if (!atom->u.remote_ref.nobracket && *s[0]) {
+			const char *to_free = *s;
+			*s = xstrfmt("[%s]", *s);
+			free((void *)to_free);
+		}
+	} else if (atom->u.remote_ref.option == RR_TRACKSHORT) {
 		if (stat_tracking_info(branch, &num_ours,
 				       &num_theirs, NULL))
 			return;
@@ -943,8 +1231,56 @@ static void fill_remote_ref_details(struct used_atom *atom, const char *refname,
 			*s = ">";
 		else
 			*s = "<>";
-	} else /* RR_NORMAL */
-		*s = refname;
+	} else
+		die("BUG: unhandled RR_* enum");
+}
+
+char *get_head_description(void)
+{
+	struct strbuf desc = STRBUF_INIT;
+	struct wt_status_state state;
+	memset(&state, 0, sizeof(state));
+	wt_status_get_state(&state, 1);
+	if (state.rebase_in_progress ||
+	    state.rebase_interactive_in_progress)
+		strbuf_addf(&desc, _("(no branch, rebasing %s)"),
+			    state.branch);
+	else if (state.bisect_in_progress)
+		strbuf_addf(&desc, _("(no branch, bisect started on %s)"),
+			    state.branch);
+	else if (state.detached_from) {
+		if (state.detached_at)
+			/* TRANSLATORS: make sure this matches
+			   "HEAD detached at " in wt-status.c */
+			strbuf_addf(&desc, _("(HEAD detached at %s)"),
+				state.detached_from);
+		else
+			/* TRANSLATORS: make sure this matches
+			   "HEAD detached from " in wt-status.c */
+			strbuf_addf(&desc, _("(HEAD detached from %s)"),
+				state.detached_from);
+	}
+	else
+		strbuf_addstr(&desc, _("(no branch)"));
+	free(state.branch);
+	free(state.onto);
+	free(state.detached_from);
+	return strbuf_detach(&desc, NULL);
+}
+
+static const char *get_symref(struct used_atom *atom, struct ref_array_item *ref)
+{
+	if (!ref->symref)
+		return "";
+	else
+		return show_ref(&atom->u.refname, ref->symref);
+}
+
+static const char *get_refname(struct used_atom *atom, struct ref_array_item *ref)
+{
+	if (ref->kind & FILTER_REFS_DETACHED_HEAD)
+		return get_head_description();
+	return show_ref(&atom->u.refname, ref->refname);
 }
 
 /*
@@ -975,10 +1311,10 @@ static void populate_value(struct ref_array_item *ref)
 		struct atom_value *v = &ref->value[i];
 		int deref = 0;
 		const char *refname;
-		const char *formatp;
 		struct branch *branch = NULL;
 
 		v->handler = append_atom;
+		v->atom = atom;
 
 		if (*name == '*') {
 			deref = 1;
@@ -986,9 +1322,9 @@ static void populate_value(struct ref_array_item *ref)
 		}
 
 		if (starts_with(name, "refname"))
-			refname = ref->refname;
+			refname = get_refname(atom, ref);
 		else if (starts_with(name, "symref"))
-			refname = ref->symref ? ref->symref : "";
+			refname = get_symref(atom, ref);
 		else if (starts_with(name, "upstream")) {
 			const char *branch_name;
 			/* only local branches may have an upstream */
@@ -1043,30 +1379,27 @@ static void populate_value(struct ref_array_item *ref)
 				v->s = " ";
 			continue;
 		} else if (starts_with(name, "align")) {
-			v->u.align = atom->u.align;
 			v->handler = align_atom_handler;
 			continue;
 		} else if (!strcmp(name, "end")) {
 			v->handler = end_atom_handler;
 			continue;
+		} else if (starts_with(name, "if")) {
+			const char *s;
+
+			if (skip_prefix(name, "if:", &s))
+				v->s = xstrdup(s);
+			v->handler = if_atom_handler;
+			continue;
+		} else if (!strcmp(name, "then")) {
+			v->handler = then_atom_handler;
+			continue;
+		} else if (!strcmp(name, "else")) {
+			v->handler = else_atom_handler;
+			continue;
 		} else
 			continue;
 
-		formatp = strchr(name, ':');
-		if (formatp) {
-			const char *arg;
-
-			formatp++;
-			if (!strcmp(formatp, "short"))
-				refname = shorten_unambiguous_ref(refname,
-						      warn_ambiguous_refs);
-			else if (skip_prefix(formatp, "strip=", &arg))
-				refname = strip_ref_components(refname, arg);
-			else
-				die(_("unknown %.*s format %s"),
-				    (int)(formatp - name), name, formatp);
-		}
-
 		if (!deref)
 			v->s = refname;
 		else
@@ -1635,10 +1968,10 @@ static void append_literal(const char *cp, const char *ep, struct ref_formatting
 	}
 }
 
-void show_ref_array_item(struct ref_array_item *info, const char *format, int quote_style)
+void format_ref_array_item(struct ref_array_item *info, const char *format,
+			   int quote_style, struct strbuf *final_buf)
 {
 	const char *cp, *sp, *ep;
-	struct strbuf *final_buf;
 	struct ref_formatting_state state = REF_FORMATTING_STATE_INIT;
 
 	state.quote_style = quote_style;
@@ -1668,9 +2001,17 @@ void show_ref_array_item(struct ref_array_item *info, const char *format, int qu
 	}
 	if (state.stack->prev)
 		die(_("format: %%(end) atom missing"));
-	final_buf = &state.stack->output;
-	fwrite(final_buf->buf, 1, final_buf->len, stdout);
+	strbuf_addbuf(final_buf, &state.stack->output);
 	pop_stack_element(&state.stack);
+}
+
+void show_ref_array_item(struct ref_array_item *info, const char *format, int quote_style)
+{
+	struct strbuf final_buf = STRBUF_INIT;
+
+	format_ref_array_item(info, format, quote_style, &final_buf);
+	fwrite(final_buf.buf, 1, final_buf.len, stdout);
+	strbuf_release(&final_buf);
 	putchar('\n');
 }
 

ref-filter.h

@@ -100,6 +100,9 @@ int parse_ref_filter_atom(const char *atom, const char *ep);
 int verify_ref_format(const char *format);
 /*  Sort the given ref_array as per the ref_sorting provided */
 void ref_array_sort(struct ref_sorting *sort, struct ref_array *array);
+/*  Based on the given format and quote_style, fill the strbuf */
+void format_ref_array_item(struct ref_array_item *info, const char *format,
+			   int quote_style, struct strbuf *final_buf);
 /*  Print the ref using the given format and quote_style */
 void show_ref_array_item(struct ref_array_item *info, const char *format, int quote_style);
 /*  Callback function for parsing the sort option */
@@ -108,6 +111,10 @@ int parse_opt_ref_sorting(const struct option *opt, const char *arg, int unset);
 struct ref_sorting *ref_default_sorting(void);
 /*  Function to parse --merged and --no-merged options */
 int parse_opt_merge_filter(const struct option *opt, const char *arg, int unset);
+/*  Get the current HEAD's description */
+char *get_head_description(void);
+/*  Set up translated strings in the output. */
+void setup_ref_filter_porcelain_msg(void);
 
 /*
  * Print a single ref, outside of any ref-filter. Note that the

t/t3203-branch-output.sh

@@ -194,7 +194,7 @@ test_expect_success 'local-branch symrefs shortened properly' '
 	git symbolic-ref refs/heads/ref-to-remote refs/remotes/origin/branch-one &&
 	cat >expect <<-\EOF &&
 	  ref-to-branch -> branch-one
-	  ref-to-remote -> refs/remotes/origin/branch-one
+	  ref-to-remote -> origin/branch-one
 	EOF
 	git branch >actual.raw &&
 	grep ref-to <actual.raw >actual &&
@@ -225,4 +225,18 @@ test_expect_success 'sort branches, ignore case' '
 	)
 '
 
+test_expect_success 'git branch --format option' '
+	cat >expect <<-\EOF &&
+	Refname is (HEAD detached from fromtag)
+	Refname is refs/heads/ambiguous
+	Refname is refs/heads/branch-one
+	Refname is refs/heads/branch-two
+	Refname is refs/heads/master
+	Refname is refs/heads/ref-to-branch
+	Refname is refs/heads/ref-to-remote
+	EOF
+	git branch --format="Refname is %(refname)" >actual &&
+	test_cmp expect actual
+'
+
 test_done

t/t6040-tracking-info.sh

@@ -44,7 +44,7 @@ b1 [ahead 1, behind 1] d
 b2 [ahead 1, behind 1] d
 b3 [behind 1] b
 b4 [ahead 2] f
-b5 g
+b5 [gone] g
 b6 c
 EOF
 

t/t6300-for-each-ref.sh

@@ -38,6 +38,7 @@ test_atom() {
 	case "$1" in
 		head) ref=refs/heads/master ;;
 		 tag) ref=refs/tags/testtag ;;
+		 sym) ref=refs/heads/sym ;;
 		   *) ref=$1 ;;
 	esac
 	printf '%s\n' "$3" >expected
@@ -50,16 +51,40 @@ test_atom() {
 
 test_atom head refname refs/heads/master
 test_atom head refname:short master
+test_atom head refname:lstrip=1 heads/master
+test_atom head refname:lstrip=2 master
+test_atom head refname:lstrip=-1 master
+test_atom head refname:lstrip=-2 heads/master
+test_atom head refname:rstrip=1 refs/heads
+test_atom head refname:rstrip=2 refs
+test_atom head refname:rstrip=-1 refs
+test_atom head refname:rstrip=-2 refs/heads
 test_atom head refname:strip=1 heads/master
 test_atom head refname:strip=2 master
+test_atom head refname:strip=-1 master
+test_atom head refname:strip=-2 heads/master
 test_atom head upstream refs/remotes/origin/master
 test_atom head upstream:short origin/master
+test_atom head upstream:lstrip=2 origin/master
+test_atom head upstream:lstrip=-2 origin/master
+test_atom head upstream:rstrip=2 refs/remotes
+test_atom head upstream:rstrip=-2 refs/remotes
+test_atom head upstream:strip=2 origin/master
+test_atom head upstream:strip=-2 origin/master
 test_atom head push refs/remotes/myfork/master
 test_atom head push:short myfork/master
+test_atom head push:lstrip=1 remotes/myfork/master
+test_atom head push:lstrip=-1 master
+test_atom head push:rstrip=1 refs/remotes/myfork
+test_atom head push:rstrip=-1 refs
+test_atom head push:strip=1 remotes/myfork/master
+test_atom head push:strip=-1 master
 test_atom head objecttype commit
 test_atom head objectsize 171
 test_atom head objectname $(git rev-parse refs/heads/master)
 test_atom head objectname:short $(git rev-parse --short refs/heads/master)
+test_atom head objectname:short=1 $(git rev-parse --short=1 refs/heads/master)
+test_atom head objectname:short=10 $(git rev-parse --short=10 refs/heads/master)
 test_atom head tree $(git rev-parse refs/heads/master^{tree})
 test_atom head parent ''
 test_atom head numparent 0
@@ -99,6 +124,8 @@ test_atom tag objecttype tag
 test_atom tag objectsize 154
 test_atom tag objectname $(git rev-parse refs/tags/testtag)
 test_atom tag objectname:short $(git rev-parse --short refs/tags/testtag)
+test_atom head objectname:short=1 $(git rev-parse --short=1 refs/heads/master)
+test_atom head objectname:short=10 $(git rev-parse --short=10 refs/heads/master)
 test_atom tag tree ''
 test_atom tag parent ''
 test_atom tag numparent ''
@@ -134,16 +161,6 @@ test_expect_success 'Check invalid atoms names are errors' '
 	test_must_fail git for-each-ref --format="%(INVALID)" refs/heads
 '
 
-test_expect_success 'arguments to :strip must be positive integers' '
-	test_must_fail git for-each-ref --format="%(refname:strip=0)" &&
-	test_must_fail git for-each-ref --format="%(refname:strip=-1)" &&
-	test_must_fail git for-each-ref --format="%(refname:strip=foo)"
-'
-
-test_expect_success 'stripping refnames too far gives an error' '
-	test_must_fail git for-each-ref --format="%(refname:strip=3)"
-'
-
 test_expect_success 'Check format specifiers are ignored in naming date atoms' '
 	git for-each-ref --format="%(authordate)" refs/heads &&
 	git for-each-ref --format="%(authordate:default) %(authordate)" refs/heads &&
@@ -164,6 +181,12 @@ test_expect_success 'Check invalid format specifiers are errors' '
 	test_must_fail git for-each-ref --format="%(authordate:INVALID)" refs/heads
 '
 
+test_expect_success 'arguments to %(objectname:short=) must be positive integers' '
+	test_must_fail git for-each-ref --format="%(objectname:short=0)" &&
+	test_must_fail git for-each-ref --format="%(objectname:short=-1)" &&
+	test_must_fail git for-each-ref --format="%(objectname:short=foo)"
+'
+
 test_date () {
 	f=$1 &&
 	committer_date=$2 &&
@@ -362,6 +385,8 @@ test_expect_success 'setup for upstream:track[short]' '
 
 test_atom head upstream:track '[ahead 1]'
 test_atom head upstream:trackshort '>'
+test_atom head upstream:track,nobracket 'ahead 1'
+test_atom head upstream:nobracket,track 'ahead 1'
 test_atom head push:track '[ahead 1]'
 test_atom head push:trackshort '>'
 
@@ -372,7 +397,7 @@ test_expect_success 'Check that :track[short] cannot be used with other atoms' '
 
 test_expect_success 'Check that :track[short] works when upstream is invalid' '
 	cat >expected <<-\EOF &&
-
+	[gone]
 
 	EOF
 	test_when_finished "git config branch.master.merge refs/heads/master" &&
@@ -554,6 +579,7 @@ test_expect_success 'Verify sort with multiple keys' '
 	test_cmp expected actual
 '
 
+
 test_expect_success 'do not dereference NULL upon %(HEAD) on unborn branch' '
 	test_when_finished "git checkout master" &&
 	git for-each-ref --format="%(HEAD) %(refname:short)" refs/heads/ >actual &&
@@ -588,4 +614,52 @@ test_expect_success 'basic atom: head contents:trailers' '
 	test_cmp expect actual.clean
 '
 
+test_expect_success 'Add symbolic ref for the following tests' '
+	git symbolic-ref refs/heads/sym refs/heads/master
+'
+
+cat >expected <<EOF
+refs/heads/master
+EOF
+
+test_expect_success 'Verify usage of %(symref) atom' '
+	git for-each-ref --format="%(symref)" refs/heads/sym >actual &&
+	test_cmp expected actual
+'
+
+cat >expected <<EOF
+heads/master
+EOF
+
+test_expect_success 'Verify usage of %(symref:short) atom' '
+	git for-each-ref --format="%(symref:short)" refs/heads/sym >actual &&
+	test_cmp expected actual
+'
+
+cat >expected <<EOF
+master
+heads/master
+EOF
+
+test_expect_success 'Verify usage of %(symref:lstrip) atom' '
+	git for-each-ref --format="%(symref:lstrip=2)" refs/heads/sym > actual &&
+	git for-each-ref --format="%(symref:lstrip=-2)" refs/heads/sym >> actual &&
+	test_cmp expected actual &&
+
+	git for-each-ref --format="%(symref:strip=2)" refs/heads/sym > actual &&
+	git for-each-ref --format="%(symref:strip=-2)" refs/heads/sym >> actual &&
+	test_cmp expected actual
+'
+
+cat >expected <<EOF
+refs
+refs/heads
+EOF
+
+test_expect_success 'Verify usage of %(symref:rstrip) atom' '
+	git for-each-ref --format="%(symref:rstrip=2)" refs/heads/sym > actual &&
+	git for-each-ref --format="%(symref:rstrip=-2)" refs/heads/sym >> actual &&
+	test_cmp expected actual
+'
+
 test_done

t/t6302-for-each-ref-filter.sh

@@ -327,4 +327,98 @@ test_expect_success 'reverse version sort' '
 	test_cmp expect actual
 '
 
+test_expect_success 'improper usage of %(if), %(then), %(else) and %(end) atoms' '
+	test_must_fail git for-each-ref --format="%(if)" &&
+	test_must_fail git for-each-ref --format="%(then) %(end)" &&
+	test_must_fail git for-each-ref --format="%(else) %(end)" &&
+	test_must_fail git for-each-ref --format="%(if) %(else) %(end)" &&
+	test_must_fail git for-each-ref --format="%(if) %(then) %(then) %(end)" &&
+	test_must_fail git for-each-ref --format="%(then) %(else) %(end)" &&
+	test_must_fail git for-each-ref --format="%(if) %(else) %(end)" &&
+	test_must_fail git for-each-ref --format="%(if) %(then) %(else)" &&
+	test_must_fail git for-each-ref --format="%(if) %(else) %(then) %(end)" &&
+	test_must_fail git for-each-ref --format="%(if) %(then) %(else) %(else) %(end)" &&
+	test_must_fail git for-each-ref --format="%(if) %(end)"
+'
+
+test_expect_success 'check %(if)...%(then)...%(end) atoms' '
+	git for-each-ref --format="%(refname)%(if)%(authorname)%(then) Author: %(authorname)%(end)" >actual &&
+	cat >expect <<-\EOF &&
+	refs/heads/master Author: A U Thor
+	refs/heads/side Author: A U Thor
+	refs/odd/spot Author: A U Thor
+	refs/tags/annotated-tag
+	refs/tags/doubly-annotated-tag
+	refs/tags/doubly-signed-tag
+	refs/tags/foo1.10 Author: A U Thor
+	refs/tags/foo1.3 Author: A U Thor
+	refs/tags/foo1.6 Author: A U Thor
+	refs/tags/four Author: A U Thor
+	refs/tags/one Author: A U Thor
+	refs/tags/signed-tag
+	refs/tags/three Author: A U Thor
+	refs/tags/two Author: A U Thor
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'check %(if)...%(then)...%(else)...%(end) atoms' '
+	git for-each-ref --format="%(if)%(authorname)%(then)%(authorname)%(else)No author%(end): %(refname)" >actual &&
+	cat >expect <<-\EOF &&
+	A U Thor: refs/heads/master
+	A U Thor: refs/heads/side
+	A U Thor: refs/odd/spot
+	No author: refs/tags/annotated-tag
+	No author: refs/tags/doubly-annotated-tag
+	No author: refs/tags/doubly-signed-tag
+	A U Thor: refs/tags/foo1.10
+	A U Thor: refs/tags/foo1.3
+	A U Thor: refs/tags/foo1.6
+	A U Thor: refs/tags/four
+	A U Thor: refs/tags/one
+	No author: refs/tags/signed-tag
+	A U Thor: refs/tags/three
+	A U Thor: refs/tags/two
+	EOF
+	test_cmp expect actual
+'
+test_expect_success 'ignore spaces in %(if) atom usage' '
+	git for-each-ref --format="%(refname:short): %(if)%(HEAD)%(then)Head ref%(else)Not Head ref%(end)" >actual &&
+	cat >expect <<-\EOF &&
+	master: Head ref
+	side: Not Head ref
+	odd/spot: Not Head ref
+	annotated-tag: Not Head ref
+	doubly-annotated-tag: Not Head ref
+	doubly-signed-tag: Not Head ref
+	foo1.10: Not Head ref
+	foo1.3: Not Head ref
+	foo1.6: Not Head ref
+	four: Not Head ref
+	one: Not Head ref
+	signed-tag: Not Head ref
+	three: Not Head ref
+	two: Not Head ref
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'check %(if:equals=<string>)' '
+	git for-each-ref --format="%(if:equals=master)%(refname:short)%(then)Found master%(else)Not master%(end)" refs/heads/ >actual &&
+	cat >expect <<-\EOF &&
+	Found master
+	Not master
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'check %(if:notequals=<string>)' '
+	git for-each-ref --format="%(if:notequals=master)%(refname:short)%(then)Not master%(else)Found master%(end)" refs/heads/ >actual &&
+	cat >expect <<-\EOF &&
+	Found master
+	Not master
+	EOF
+	test_cmp expect actual
+'
+
 test_done