for-each-ref: add new option to include root refs

The git-for-each-ref(1) command doesn't provide a way to print root refs
i.e pseudorefs and HEAD with the regular "refs/" prefixed refs.

This commit adds a new option "--include-root-refs" to
git-for-each-ref(1). When used this would also print pseudorefs and HEAD
for the current worktree.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-for-each-ref.txt

@@ -10,7 +10,7 @@ SYNOPSIS
 [verse]
 'git for-each-ref' [--count=<count>] [--shell|--perl|--python|--tcl]
 		   [(--sort=<key>)...] [--format=<format>]
-		   [ --stdin | <pattern>... ]
+		   [--include-root-refs] [ --stdin | <pattern>... ]
 		   [--points-at=<object>]
 		   [--merged[=<object>]] [--no-merged[=<object>]]
 		   [--contains[=<object>]] [--no-contains[=<object>]]
@@ -105,6 +105,9 @@ TAB %(refname)`.
 	any excluded pattern(s) are shown. Matching is done using the
 	same rules as `<pattern>` above.
 
+--include-root-refs::
+	List root refs (HEAD and pseudorefs) apart from regular refs.
+
 FIELD NAMES
 -----------
 

builtin/for-each-ref.c

@@ -20,10 +20,10 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 {
 	struct ref_sorting *sorting;
 	struct string_list sorting_options = STRING_LIST_INIT_DUP;
-	int icase = 0;
+	int icase = 0, include_root_refs = 0, from_stdin = 0;
 	struct ref_filter filter = REF_FILTER_INIT;
 	struct ref_format format = REF_FORMAT_INIT;
-	int from_stdin = 0;
+	unsigned int flags = FILTER_REFS_REGULAR;
 	struct strvec vec = STRVEC_INIT;
 
 	struct option opts[] = {
@@ -53,6 +53,7 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 		OPT_NO_CONTAINS(&filter.no_commit, N_("print only refs which don't contain the commit")),
 		OPT_BOOL(0, "ignore-case", &icase, N_("sorting and filtering are case insensitive")),
 		OPT_BOOL(0, "stdin", &from_stdin, N_("read reference patterns from stdin")),
+		OPT_BOOL(0, "include-root-refs", &include_root_refs, N_("also include HEAD ref and pseudorefs")),
 		OPT_END(),
 	};
 
@@ -96,8 +97,11 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 		filter.name_patterns = argv;
 	}
 
+	if (include_root_refs)
+		flags |= FILTER_REFS_ROOT_REFS;
+
 	filter.match_as_path = 1;
-	filter_and_format_refs(&filter, FILTER_REFS_REGULAR, sorting, &format);
+	filter_and_format_refs(&filter, flags, sorting, &format);
 
 	ref_filter_clear(&filter);
 	ref_sorting_release(sorting);

ref-filter.c

@@ -2622,6 +2622,12 @@ static int for_each_fullref_in_pattern(struct ref_filter *filter,
 				       each_ref_fn cb,
 				       void *cb_data)
 {
+	if (filter->kind == FILTER_REFS_KIND_MASK) {
+		/* In this case, we want to print all refs including root refs. */
+		return refs_for_each_include_root_refs(get_main_ref_store(the_repository),
+						       cb, cb_data);
+	}
+
 	if (!filter->match_as_path) {
 		/*
 		 * in this case, the patterns are applied after
@@ -2744,6 +2750,9 @@ static int ref_kind_from_refname(const char *refname)
 			return ref_kind[i].kind;
 	}
 
+	if (is_pseudoref(get_main_ref_store(the_repository), refname))
+		return FILTER_REFS_PSEUDOREFS;
+
 	return FILTER_REFS_OTHERS;
 }
 
@@ -2775,7 +2784,16 @@ static struct ref_array_item *apply_ref_filter(const char *refname, const struct
 
 	/* Obtain the current ref kind from filter_ref_kind() and ignore unwanted refs. */
 	kind = filter_ref_kind(filter, refname);
-	if (!(kind & filter->kind))
+
+	/*
+	 * Generally HEAD refs are printed with special description denoting a rebase,
+	 * detached state and so forth. This is useful when only printing the HEAD ref
+	 * But when it is being printed along with other pseudorefs, it makes sense to
+	 * keep the formatting consistent. So we mask the type to act like a pseudoref.
+	 */
+	if (filter->kind == FILTER_REFS_KIND_MASK && kind == FILTER_REFS_DETACHED_HEAD)
+		kind = FILTER_REFS_PSEUDOREFS;
+	else if (!(kind & filter->kind))
 		return NULL;
 
 	if (!filter_pattern_match(filter, refname))
@@ -3043,7 +3061,13 @@ static int do_filter_refs(struct ref_filter *filter, unsigned int type, each_ref
 			ret = for_each_fullref_in("refs/tags/", fn, cb_data);
 		else if (filter->kind & FILTER_REFS_REGULAR)
 			ret = for_each_fullref_in_pattern(filter, fn, cb_data);
-		if (!ret && (filter->kind & FILTER_REFS_DETACHED_HEAD))
+
+		/*
+		 * When printing all ref types, HEAD is already included,
+		 * so we don't want to print HEAD again.
+		 */
+		if (!ret && (filter->kind != FILTER_REFS_KIND_MASK) &&
+		    (filter->kind & FILTER_REFS_DETACHED_HEAD))
 			head_ref(fn, cb_data);
 	}
 

ref-filter.h

@@ -22,7 +22,10 @@
 #define FILTER_REFS_REGULAR        (FILTER_REFS_TAGS | FILTER_REFS_BRANCHES | \
 				    FILTER_REFS_REMOTES | FILTER_REFS_OTHERS)
 #define FILTER_REFS_DETACHED_HEAD  0x0020
-#define FILTER_REFS_KIND_MASK      (FILTER_REFS_REGULAR | FILTER_REFS_DETACHED_HEAD)
+#define FILTER_REFS_PSEUDOREFS     0x0040
+#define FILTER_REFS_ROOT_REFS      (FILTER_REFS_DETACHED_HEAD | FILTER_REFS_PSEUDOREFS)
+#define FILTER_REFS_KIND_MASK      (FILTER_REFS_REGULAR | FILTER_REFS_DETACHED_HEAD | \
+				    FILTER_REFS_PSEUDOREFS)
 
 struct atom_value;
 struct ref_sorting;

refs/reftable-backend.c

@@ -364,12 +364,15 @@ static int reftable_ref_iterator_advance(struct ref_iterator *ref_iterator)
 			break;
 
 		/*
-		 * The files backend only lists references contained in
+		 * The files backend only lists references contained in "refs/" unless
-		 * "refs/". We emulate the same behaviour here and thus skip
+		 * the root refs are to be included. We emulate the same behaviour here.
-		 * all references that don't start with this prefix.
 		 */
-		if (!starts_with(iter->ref.refname, "refs/"))
+		if (!starts_with(iter->ref.refname, "refs/") &&
+		    !(iter->flags & DO_FOR_EACH_INCLUDE_ROOT_REFS &&
+		     (is_pseudoref(&iter->refs->base, iter->ref.refname) ||
+		      is_headref(&iter->refs->base, iter->ref.refname)))) {
 			continue;
+		}
 
 		if (iter->prefix &&
 		    strncmp(iter->prefix, iter->ref.refname, strlen(iter->prefix))) {

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

@@ -31,6 +31,37 @@ test_expect_success 'setup some history and refs' '
 	git update-ref refs/odd/spot main
 '
 
+test_expect_success '--include-root-refs pattern prints pseudorefs' '
+	cat >expect <<-\EOF &&
+	HEAD
+	ORIG_HEAD
+	refs/heads/main
+	refs/heads/side
+	refs/odd/spot
+	refs/tags/annotated-tag
+	refs/tags/doubly-annotated-tag
+	refs/tags/doubly-signed-tag
+	refs/tags/four
+	refs/tags/one
+	refs/tags/signed-tag
+	refs/tags/three
+	refs/tags/two
+	EOF
+	git update-ref ORIG_HEAD main &&
+	git for-each-ref --format="%(refname)" --include-root-refs >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--include-root-refs with other patterns' '
+	cat >expect <<-\EOF &&
+	HEAD
+	ORIG_HEAD
+	EOF
+	git update-ref ORIG_HEAD main &&
+	git for-each-ref --format="%(refname)" --include-root-refs "*HEAD" >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'filtering with --points-at' '
 	cat >expect <<-\EOF &&
 	refs/heads/main