[PATCH v2 00/10] Port tag.c to use ref-filter APIs

This is part of my GSoC project to unify git tag -l, git branch -l,
git for-each-ref
This patch series is continued from:
http://article.gmane.org/gmane.comp.version-control.git/273569

The previous RFC version is here:
http://thread.gmane.org/gmane.comp.version-control.git/272654

Changes in this version:
* Cleanup Documentation/tag
* Fixed grammatical errors
* Fixed a small merge conflict
* Other small changes

 Documentation/git-tag.txt |  39 ++++++++++---
 builtin/for-each-ref.c    |   3 +-
 builtin/tag.c             | 368
++++++++++++++++++++------------------------------------------------------------------------------------------------
 ref-filter.c              |  95 ++++++++++++++++++++++++++++--
 ref-filter.h              |   7 ++-
 t/t7004-tag.sh            |  51 +++++++++++++---
 6 files changed, 234 insertions(+), 329 deletions(-)

-- 
Regards,
Karthik Nayak

Add support for %(refname:shortalign=X) where X is a number.
This will print a shortened refname aligned to the left
followed by spaces for a total length of X characters.
If X is less than the shortened refname size, the entire
shortened refname is printed.

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 ref-filter.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/ref-filter.c b/ref-filter.c
index dd0709d..3098497 100644
--- a/ref-filter.c
+++ b/ref-filter.c

@@ -10,6 +10,7 @@
 #include "quote.h"
 #include "ref-filter.h"
 #include "revision.h"
+#include "utf8.h"
 
 typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME } cmp_type;
 

@@ -695,7 +696,23 @@ static void populate_value(struct ref_array_item *ref)
 			int num_ours, num_theirs;
 
 			formatp++;
-			if (!strcmp(formatp, "short"))
+			if (starts_with(formatp, "shortalign=")) {
+				const char *valp, *short_refname = NULL;
+				int val, len;
+
+				skip_prefix(formatp, "shortalign=", &valp);
+				val = atoi(valp);
+				refname = short_refname = shorten_unambiguous_ref(refname,
+										  warn_ambiguous_refs);
+				len = utf8_strwidth(refname);
+				if (val > len) {
+					struct strbuf buf = STRBUF_INIT;
+					strbuf_addstr(&buf, refname);
+					strbuf_addchars(&buf, ' ', val - len);
+					free((char *)short_refname);
+					refname = strbuf_detach(&buf, NULL);
+				}
+			} else if (!strcmp(formatp, "short"))
 				refname = shorten_unambiguous_ref(refname,
 						      warn_ambiguous_refs);
 			else if (!strcmp(formatp, "track") &&

-- 
2.4.5

Since 'ref-filter' only has an option to match path names
add an option for regular pattern matching.

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 builtin/for-each-ref.c |  1 +
 ref-filter.c           | 25 ++++++++++++++++++++++++-
 ref-filter.h           |  3 ++-
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index e4a4f8a..3ad6a64 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c

@@ -68,6 +68,7 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 	git_config(git_default_config, NULL);
 
 	filter.name_patterns = argv;
+	filter.match_as_path = 1;
 	filter_refs(&array, &filter, FILTER_REFS_ALL | FILTER_REFS_INCLUDE_BROKEN);
 	ref_array_sort(sorting, &array);
 

diff --git a/ref-filter.c b/ref-filter.c
index 1516cd1..0e19f44 100644
--- a/ref-filter.c
+++ b/ref-filter.c

@@ -956,6 +956,20 @@ static int commit_contains(struct ref_filter *filter, struct commit *commit)
 
 /*
  * Return 1 if the refname matches one of the patterns, otherwise 0.
+ * A pattern can be a literal prefix (e.g. a refname "refs/heads/master"
+ * matches a pattern "refs/heads/m") or a wildcard (e.g. the same ref
+ * matches "refs/heads/m*",too).
+ */
+static int match_pattern(const char **patterns, const char *refname)
+{
+	for (; *patterns; patterns++)
+		if (!wildmatch(*patterns, refname, 0, NULL))
+			return 1;
+	return 0;
+}
+
+/*
+ * Return 1 if the refname matches one of the patterns, otherwise 0.
  * A pattern can be path prefix (e.g. a refname "refs/heads/master"
  * matches a pattern "refs/heads/") or a wildcard (e.g. the same ref
  * matches "refs/heads/m*",too).

@@ -979,6 +993,15 @@ static int match_name_as_path(const char **pattern, const char *refname)
 	return 0;
 }
 
+static int filter_pattern_match(struct ref_filter *filter, const char *refname)
+{
+	if (!*filter->name_patterns)
+		return 1;
+	if (filter->match_as_path)
+		return match_name_as_path(filter->name_patterns, refname);
+	return match_pattern(filter->name_patterns, refname);
+}
+
 /*
  * Given a ref (sha1, refname), check if the ref belongs to the array
  * of sha1s. If the given ref is a tag, check if the given tag points

@@ -1047,7 +1070,7 @@ static int ref_filter_handler(const char *refname, const struct object_id *oid,
 		return 0;
 	}
 
-	if (*filter->name_patterns && !match_name_as_path(filter->name_patterns, refname))
+	if (!filter_pattern_match(filter, refname))
 		return 0;
 
 	if (filter->points_at.nr && !match_points_at(&filter->points_at, oid->hash, refname))

diff --git a/ref-filter.h b/ref-filter.h
index 5247475..633108c 100644
--- a/ref-filter.h
+++ b/ref-filter.h

@@ -54,7 +54,8 @@ struct ref_filter {
 	} merge;
 	struct commit *merge_commit;
 
-	unsigned int with_commit_tag_algo : 1;
+	unsigned int with_commit_tag_algo : 1,
+		match_as_path : 1;
 	unsigned int lines;
 };
 

-- 
2.4.5

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 Documentation/git-tag.txt | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 034d10d..4b04c2b 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt

@@ -14,7 +14,6 @@ SYNOPSIS
 'git tag' -d <tagname>...
 'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
 	[--column[=<options>] | --no-column] [<pattern>...]
-	[<pattern>...]
 'git tag' -v <tagname>...
 
 DESCRIPTION

-- 
2.4.5

Add support to sort by version using the "v:refname" and
"version:refname" option. This is achieved by using the
'version_cmp()' function as the comparing function for qsort.

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 ref-filter.c | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)

diff --git a/ref-filter.c b/ref-filter.c
index 1b088b1..1516cd1 100644
--- a/ref-filter.c
+++ b/ref-filter.c

@@ -11,8 +11,9 @@
 #include "ref-filter.h"
 #include "revision.h"
 #include "utf8.h"
+#include "version.h"
 
-typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME } cmp_type;
+typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME, FIELD_VER } cmp_type;
 
 static struct {
 	const char *name;

@@ -54,6 +55,8 @@ static struct {
 	{ "flag" },
 	{ "HEAD" },
 	{ "color" },
+	{ "version", FIELD_VER },
+	{ "v", FIELD_VER },
 };
 
 /*

@@ -630,7 +633,9 @@ static void populate_value(struct ref_array_item *ref)
 			name++;
 		}
 
-		if (starts_with(name, "refname"))
+		if (starts_with(name, "refname") ||
+		    starts_with(name, "version:") ||
+		    starts_with(name, "v:"))
 			refname = ref->refname;
 		else if (starts_with(name, "symref"))
 			refname = ref->symref ? ref->symref : "";

@@ -696,7 +701,13 @@ static void populate_value(struct ref_array_item *ref)
 			int num_ours, num_theirs;
 
 			formatp++;
-			if (starts_with(formatp, "shortalign=")) {
+			if (starts_with(name, "version") || starts_with(name, "v")) {
+				if (strcmp(formatp, "refname"))
+					die("unknown %.*s format %s",
+					    (int)(formatp - name), name, formatp);
+				v->s = refname;
+				continue;
+			} else if (starts_with(formatp, "shortalign=")) {
 				const char *valp, *short_refname = NULL;
 				int val, len;
 

@@ -1176,6 +1187,9 @@ static int cmp_ref_sorting(struct ref_sorting *s, struct ref_array_item *a, stru
 	case FIELD_STR:
 		cmp = strcmp(va->s, vb->s);
 		break;
+	case FIELD_VER:
+		cmp = versioncmp(va->s, vb->s);
+		break;
 	default:
 		if (va->ul < vb->ul)
 			cmp = -1;

-- 
2.4.5

Make 'tag.c' use 'ref-filter' data structures and make changes to
support the new data structures. This is a part of the process
of porting 'tag.c' to use 'ref-filter' APIs.

This is a temporary step before porting 'tag.c' to use 'ref-filter'
completely. As this is a temporary step, most of the code
introduced here will be removed when 'tag.c' is ported over to use
'ref-filter' APIs

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 builtin/tag.c | 106 +++++++++++++++++++++++++++++++---------------------------
 1 file changed, 57 insertions(+), 49 deletions(-)

diff --git a/builtin/tag.c b/builtin/tag.c
index 3b6a6cc..bbda0c6 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c

@@ -17,6 +17,7 @@
 #include "gpg-interface.h"
 #include "sha1-array.h"
 #include "column.h"
+#include "ref-filter.h"
 
 static const char * const git_tag_usage[] = {
 	N_("git tag [-a | -s | -u <key-id>] [-f] [-m <msg> | -F <file>] <tagname> [<head>]"),

@@ -34,15 +35,6 @@ static const char * const git_tag_usage[] = {
 
 static int tag_sort;
 
-struct tag_filter {
-	const char **patterns;
-	int lines;
-	int sort;
-	struct string_list tags;
-	struct commit_list *with_commit;
-};
-
-static struct sha1_array points_at;
 static unsigned int colopts;
 
 static int match_pattern(const char **patterns, const char *ref)

@@ -61,19 +53,20 @@ static int match_pattern(const char **patterns, const char *ref)
  * removed as we port tag.c to use the ref-filter APIs.
  */
 static const unsigned char *match_points_at(const char *refname,
-					    const unsigned char *sha1)
+					    const unsigned char *sha1,
+					    struct sha1_array *points_at)
 {
 	const unsigned char *tagged_sha1 = NULL;
 	struct object *obj;
 
-	if (sha1_array_lookup(&points_at, sha1) >= 0)
+	if (sha1_array_lookup(points_at, sha1) >= 0)
 		return sha1;
 	obj = parse_object(sha1);
 	if (!obj)
 		die(_("malformed object at '%s'"), refname);
 	if (obj->type == OBJ_TAG)
 		tagged_sha1 = ((struct tag *)obj)->tagged->sha1;
-	if (tagged_sha1 && sha1_array_lookup(&points_at, tagged_sha1) >= 0)
+	if (tagged_sha1 && sha1_array_lookup(points_at, tagged_sha1) >= 0)
 		return tagged_sha1;
 	return NULL;
 }

@@ -228,12 +221,24 @@ free_return:
 	free(buf);
 }
 
+static void ref_array_append(struct ref_array *array, const char *refname)
+{
+	size_t len = strlen(refname);
+	struct ref_array_item *ref = xcalloc(1, sizeof(struct ref_array_item) + len + 1);
+	memcpy(ref->refname, refname, len);
+	ref->refname[len] = '\0';
+	REALLOC_ARRAY(array->items, array->nr + 1);
+	array->items[array->nr++] = ref;
+}
+
 static int show_reference(const char *refname, const struct object_id *oid,
 			  int flag, void *cb_data)
 {
-	struct tag_filter *filter = cb_data;
+	struct ref_filter_cbdata *data = cb_data;
+	struct ref_array *array = data->array;
+	struct ref_filter *filter = data->filter;
 
-	if (match_pattern(filter->patterns, refname)) {
+	if (match_pattern(filter->name_patterns, refname)) {
 		if (filter->with_commit) {
 			struct commit *commit;
 

@@ -244,12 +249,12 @@ static int show_reference(const char *refname, const struct object_id *oid,
 				return 0;
 		}
 
-		if (points_at.nr && !match_points_at(refname, oid->hash))
+		if (filter->points_at.nr && !match_points_at(refname, oid->hash, &filter->points_at))
 			return 0;
 
 		if (!filter->lines) {
-			if (filter->sort)
-				string_list_append(&filter->tags, refname);
+			if (tag_sort)
+				ref_array_append(array, refname);
 			else
 				printf("%s\n", refname);
 			return 0;

@@ -264,36 +269,36 @@ static int show_reference(const char *refname, const struct object_id *oid,
 
 static int sort_by_version(const void *a_, const void *b_)
 {
-	const struct string_list_item *a = a_;
-	const struct string_list_item *b = b_;
-	return versioncmp(a->string, b->string);
+	const struct ref_array_item *a = *((struct ref_array_item **)a_);
+	const struct ref_array_item *b = *((struct ref_array_item **)b_);
+	return versioncmp(a->refname, b->refname);
 }
 
-static int list_tags(const char **patterns, int lines,
-		     struct commit_list *with_commit, int sort)
+static int list_tags(struct ref_filter *filter, int sort)
 {
-	struct tag_filter filter;
+	struct ref_array array;
+	struct ref_filter_cbdata data;
+
+	memset(&array, 0, sizeof(array));
+	data.array = &array;
+	data.filter = filter;
 
-	filter.patterns = patterns;
-	filter.lines = lines;
-	filter.sort = sort;
-	filter.with_commit = with_commit;
-	memset(&filter.tags, 0, sizeof(filter.tags));
-	filter.tags.strdup_strings = 1;
+	if (filter->lines == -1)
+		filter->lines = 0;
 
-	for_each_tag_ref(show_reference, (void *)&filter);
+	for_each_tag_ref(show_reference, &data);
 	if (sort) {
 		int i;
 		if ((sort & SORT_MASK) == VERCMP_SORT)
-			qsort(filter.tags.items, filter.tags.nr,
-			      sizeof(struct string_list_item), sort_by_version);
+			qsort(array.items, array.nr,
+			      sizeof(struct ref_array_item *), sort_by_version);
 		if (sort & REVERSE_SORT)
-			for (i = filter.tags.nr - 1; i >= 0; i--)
-				printf("%s\n", filter.tags.items[i].string);
+			for (i = array.nr - 1; i >= 0; i--)
+				printf("%s\n", array.items[i]->refname);
 		else
-			for (i = 0; i < filter.tags.nr; i++)
-				printf("%s\n", filter.tags.items[i].string);
-		string_list_clear(&filter.tags, 0);
+			for (i = 0; i < array.nr; i++)
+				printf("%s\n", array.items[i]->refname);
+		ref_array_clear(&array);
 	}
 	return 0;
 }

@@ -574,16 +579,16 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	const char *object_ref, *tag;
 	struct create_tag_options opt;
 	char *cleanup_arg = NULL;
-	int annotate = 0, force = 0, lines = -1;
+	int annotate = 0, force = 0;
 	int cmdmode = 0;
 	const char *msgfile = NULL, *keyid = NULL;
 	struct msg_arg msg = { 0, STRBUF_INIT };
-	struct commit_list *with_commit = NULL;
 	struct ref_transaction *transaction;
 	struct strbuf err = STRBUF_INIT;
+	struct ref_filter filter;
 	struct option options[] = {
 		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
-		{ OPTION_INTEGER, 'n', NULL, &lines, N_("n"),
+		{ OPTION_INTEGER, 'n', NULL, &filter.lines, N_("n"),
 				N_("print <n> lines of each tag message"),
 				PARSE_OPT_OPTARG, NULL, 1 },
 		OPT_CMDMODE('d', "delete", &cmdmode, N_("delete tags"), 'd'),

@@ -604,14 +609,14 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 
 		OPT_GROUP(N_("Tag listing options")),
 		OPT_COLUMN(0, "column", &colopts, N_("show tag list in columns")),
-		OPT_CONTAINS(&with_commit, N_("print only tags that contain the commit")),
-		OPT_WITH(&with_commit, N_("print only tags that contain the commit")),
+		OPT_CONTAINS(&filter.with_commit, N_("print only tags that contain the commit")),
+		OPT_WITH(&filter.with_commit, N_("print only tags that contain the commit")),
 		{
 			OPTION_CALLBACK, 0, "sort", &tag_sort, N_("type"), N_("sort tags"),
 			PARSE_OPT_NONEG, parse_opt_sort
 		},
 		{
-			OPTION_CALLBACK, 0, "points-at", &points_at, N_("object"),
+			OPTION_CALLBACK, 0, "points-at", &filter.points_at, N_("object"),
 			N_("print only tags of the object"), 0, parse_opt_object_name
 		},
 		OPT_END()

@@ -620,6 +625,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	git_config(git_tag_config, NULL);
 
 	memset(&opt, 0, sizeof(opt));
+	memset(&filter, 0, sizeof(filter));
+	filter.lines = -1;
 
 	argc = parse_options(argc, argv, prefix, options, git_tag_usage, 0);
 

@@ -636,7 +643,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 		usage_with_options(git_tag_usage, options);
 
 	finalize_colopts(&colopts, -1);
-	if (cmdmode == 'l' && lines != -1) {
+	if (cmdmode == 'l' && filter.lines != -1) {
 		if (explicitly_enable_column(colopts))
 			die(_("--column and -n are incompatible"));
 		colopts = 0;

@@ -649,18 +656,19 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 			copts.padding = 2;
 			run_column_filter(colopts, &copts);
 		}
-		if (lines != -1 && tag_sort)
+		if (filter.lines != -1 && tag_sort)
 			die(_("--sort and -n are incompatible"));
-		ret = list_tags(argv, lines == -1 ? 0 : lines, with_commit, tag_sort);
+		filter.name_patterns = argv;
+		ret = list_tags(&filter, tag_sort);
 		if (column_active(colopts))
 			stop_column_filter();
 		return ret;
 	}
-	if (lines != -1)
+	if (filter.lines != -1)
 		die(_("-n option is only allowed with -l."));
-	if (with_commit)
+	if (filter.with_commit)
 		die(_("--contains option is only allowed with -l."));
-	if (points_at.nr)
+	if (filter.points_at.nr)
 		die(_("--points-at option is only allowed with -l."));
 	if (cmdmode == 'd')
 		return for_each_tag_name(argv, delete_tag);

-- 
2.4.5

Add an option in 'filter_refs()' to use 'for_each_tag_ref()'
and filter refs. This type checking is done by adding a
'FILTER_REFS_TAGS' in 'ref-filter.h'

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 ref-filter.c | 2 ++
 ref-filter.h | 1 +
 2 files changed, 3 insertions(+)

diff --git a/ref-filter.c b/ref-filter.c
index 3098497..e690177 100644
--- a/ref-filter.c
+++ b/ref-filter.c

@@ -1152,6 +1152,8 @@ int filter_refs(struct ref_array *array, struct ref_filter *filter, unsigned int
 		ret = for_each_rawref(ref_filter_handler, &ref_cbdata);
 	else if (type & FILTER_REFS_ALL)
 		ret = for_each_ref(ref_filter_handler, &ref_cbdata);
+	else if (type & FILTER_REFS_TAGS)
+		ret = for_each_tag_ref(ref_filter_handler, &ref_cbdata);
 	else if (type)
 		die("filter_refs: invalid type");
 

diff --git a/ref-filter.h b/ref-filter.h
index 6bf27d8..449ddb8 100644
--- a/ref-filter.h
+++ b/ref-filter.h

@@ -15,6 +15,7 @@
 
 #define FILTER_REFS_INCLUDE_BROKEN 0x1
 #define FILTER_REFS_ALL 0x2
+#define FILTER_REFS_TAGS 0x4
 
 struct atom_value {
 	const char *s;

-- 
2.4.5

In 'tag.c' we can print N lines from the annotation of the tag
using the '-n<num>' option. Copy code from 'tag.c' to 'ref-filter'
and modify 'ref-filter' to support printing of N lines from the
annotation of tags.

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 builtin/for-each-ref.c |  2 +-
 builtin/tag.c          |  4 ++++
 ref-filter.c           | 48 +++++++++++++++++++++++++++++++++++++++++++++++-
 ref-filter.h           |  3 ++-
 4 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index 40f343b..e4a4f8a 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c

@@ -74,7 +74,7 @@ int cmd_for_each_ref(int argc, const char **argv, const char *prefix)
 	if (!maxcount || array.nr < maxcount)
 		maxcount = array.nr;
 	for (i = 0; i < maxcount; i++)
-		show_ref_array_item(array.items[i], format, quote_style);
+		show_ref_array_item(array.items[i], format, quote_style, 0);
 	ref_array_clear(&array);
 	return 0;
 }

diff --git a/builtin/tag.c b/builtin/tag.c
index 071d001..3b6a6cc 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c

@@ -185,6 +185,10 @@ static enum contains_result contains(struct commit *candidate,
 	return contains_test(candidate, want);
 }
 
+/*
+ * Currently dupplicated in ref-filter, will eventually be removed as
+ * we port tag.c to use ref-filter APIs.
+ */
 static void show_tag_lines(const struct object_id *oid, int lines)
 {
 	int i;

diff --git a/ref-filter.c b/ref-filter.c
index e690177..1b088b1 100644
--- a/ref-filter.c
+++ b/ref-filter.c

@@ -1273,7 +1273,48 @@ static void emit(const char *cp, const char *ep)
 	}
 }
 
-void show_ref_array_item(struct ref_array_item *info, const char *format, int quote_style)
+/* Print 'lines' no of lines of a given oid */
+static void show_tag_lines(const struct object_id *oid, int lines)
+{
+	int i;
+	unsigned long size;
+	enum object_type type;
+	char *buf, *sp, *eol;
+	size_t len;
+
+	buf = read_sha1_file(oid->hash, &type, &size);
+	if (!buf)
+		die_errno("unable to read object %s", oid_to_hex(oid));
+	if (type != OBJ_COMMIT && type != OBJ_TAG)
+		goto free_return;
+	if (!size)
+		die("an empty %s object %s?",
+		    typename(type), oid_to_hex(oid));
+
+	/* skip header */
+	sp = strstr(buf, "\n\n");
+	if (!sp)
+		goto free_return;
+
+	/* only take up to "lines" lines, and strip the signature from a tag */
+	if (type == OBJ_TAG)
+		size = parse_signature(buf, size);
+	for (i = 0, sp += 2; i < lines && sp < buf + size; i++) {
+		if (i)
+			printf("\n    ");
+		eol = memchr(sp, '\n', size - (sp - buf));
+		len = eol ? eol - sp : size - (sp - buf);
+		fwrite(sp, len, 1, stdout);
+		if (!eol)
+			break;
+		sp = eol + 1;
+	}
+free_return:
+	free(buf);
+}
+
+void show_ref_array_item(struct ref_array_item *info, const char *format,
+			 int quote_style, unsigned int lines)
 {
 	const char *cp, *sp, *ep;
 

@@ -1299,6 +1340,11 @@ void show_ref_array_item(struct ref_array_item *info, const char *format, int qu
 		resetv.s = color;
 		print_value(&resetv, quote_style);
 	}
+	if (lines > 0) {
+		struct object_id oid;
+		hashcpy(oid.hash, info->objectname);
+		show_tag_lines(&oid, lines);
+	}
 	putchar('\n');
 }
 

diff --git a/ref-filter.h b/ref-filter.h
index 449ddb8..5247475 100644
--- a/ref-filter.h
+++ b/ref-filter.h

@@ -55,6 +55,7 @@ struct ref_filter {
 	struct commit *merge_commit;
 
 	unsigned int with_commit_tag_algo : 1;
+	unsigned int lines;
 };
 
 struct ref_filter_cbdata {

@@ -87,7 +88,7 @@ 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);
 /*  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);
+void show_ref_array_item(struct ref_array_item *info, const char *format, int quote_style, unsigned int lines);
 /*  Callback function for parsing the sort option */
 int parse_opt_ref_sorting(const struct option *opt, const char *arg, int unset);
 /*  Default sort option based on refname */

-- 
2.4.5

Make 'tag.c' use 'ref-filter' APIs for iterating through refs
sorting and printing of refs. This removes most of the code
used in 'tag.c' replacing it with calls to the 'ref-filter'
library.

Make 'tag.c' use the 'filter_refs()' function provided by
'ref-filter' to filter out tags based on the options set.

For printing tags we use 'show_ref_array_item()' function
provided by 'ref-filter'.

We improve the sorting option provided by 'tag.c' by using the
sorting options provided by 'ref-filter'. This causes the test
'invalid sort parameter on command line' in t7004 to fail, as
'ref-filter' throws an error for all sorting fields which are
incorrect. The test is changed to reflect the same.

Modify documentation for the same.

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
  Documentation/git-tag.txt |  16 ++-
  builtin/tag.c             | 343 
++++++----------------------------------------
  t/t7004-tag.sh            |   8 +-
  3 files changed, 50 insertions(+), 317 deletions(-)

diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 4b04c2b..02fb363 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt

@@ -13,7 +13,7 @@ SYNOPSIS
  	<tagname> [<commit> | <object>]
  'git tag' -d <tagname>...
  'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
-	[--column[=<options>] | --no-column] [<pattern>...]
+	[--column[=<options>] | --no-column] [--sort=<key>] [<pattern>...]
  'git tag' -v <tagname>...

  DESCRIPTION

@@ -94,14 +94,16 @@ OPTIONS
  	using fnmatch(3)).  Multiple patterns may be given; if any of
  	them matches, the tag is shown.

---sort=<type>::
-	Sort in a specific order. Supported type is "refname"
-	(lexicographic order), "version:refname" or "v:refname" (tag
+--sort=<key>::
+	Sort based on the key given.  Prefix `-` to sort in
+	descending order of the value. You may use the --sort=<key> option
+	multiple times, in which case the last key becomes the primary
+	key. Also supports "version:refname" or "v:refname" (tag
  	names are treated as versions). The "version:refname" sort
  	order can also be affected by the
-	"versionsort.prereleaseSuffix" configuration variable. Prepend
-	"-" to reverse sort order. When this option is not given, the
-	sort order defaults to the value configured for the 'tag.sort'
+	"versionsort.prereleaseSuffix" configuration variable.
+	The keys supported are the same as those in `git for-each-ref`.
+	Sort order defaults to the value configured for the 'tag.sort'
  	variable if it exists, or lexicographic order otherwise. See
  	linkgit:git-config[1].

diff --git a/builtin/tag.c b/builtin/tag.c
index bbda0c6..36f8019 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c

@@ -28,278 +28,34 @@ static const char * const git_tag_usage[] = {
  	NULL
  };

-#define STRCMP_SORT     0	/* must be zero */
-#define VERCMP_SORT     1
-#define SORT_MASK       0x7fff
-#define REVERSE_SORT    0x8000
-
-static int tag_sort;
-
  static unsigned int colopts;

-static int match_pattern(const char **patterns, const char *ref)
-{
-	/* no pattern means match everything */
-	if (!*patterns)
-		return 1;
-	for (; *patterns; patterns++)
-		if (!wildmatch(*patterns, ref, 0, NULL))
-			return 1;
-	return 0;
-}
-
-/*
- * This is currently duplicated in ref-filter.c, and will eventually be
- * removed as we port tag.c to use the ref-filter APIs.
- */
-static const unsigned char *match_points_at(const char *refname,
-					    const unsigned char *sha1,
-					    struct sha1_array *points_at)
-{
-	const unsigned char *tagged_sha1 = NULL;
-	struct object *obj;
-
-	if (sha1_array_lookup(points_at, sha1) >= 0)
-		return sha1;
-	obj = parse_object(sha1);
-	if (!obj)
-		die(_("malformed object at '%s'"), refname);
-	if (obj->type == OBJ_TAG)
-		tagged_sha1 = ((struct tag *)obj)->tagged->sha1;
-	if (tagged_sha1 && sha1_array_lookup(points_at, tagged_sha1) >= 0)
-		return tagged_sha1;
-	return NULL;
-}
-
-static int in_commit_list(const struct commit_list *want, struct commit *c)
-{
-	for (; want; want = want->next)
-		if (!hashcmp(want->item->object.sha1, c->object.sha1))
-			return 1;
-	return 0;
-}
-
-/*
- * The entire code segment for supporting the --contains option has been
- * copied over to ref-filter.{c,h}. This will be deleted evetually when
- * we port tag.c to use ref-filter APIs.
- */
-enum contains_result {
-	CONTAINS_UNKNOWN = -1,
-	CONTAINS_NO = 0,
-	CONTAINS_YES = 1
-};
-
-/*
- * Test whether the candidate or one of its parents is contained in the 

list.
- * Do not recurse to find out, though, but return -1 if inconclusive.
- */
-static enum contains_result contains_test(struct commit *candidate,
-			    const struct commit_list *want)
-{
-	/* was it previously marked as containing a want commit? */
-	if (candidate->object.flags & TMP_MARK)
-		return 1;
-	/* or marked as not possibly containing a want commit? */
-	if (candidate->object.flags & UNINTERESTING)
-		return 0;
-	/* or are we it? */
-	if (in_commit_list(want, candidate)) {
-		candidate->object.flags |= TMP_MARK;
-		return 1;
-	}
-
-	if (parse_commit(candidate) < 0)
-		return 0;
-
-	return -1;
-}
-
-/*
- * Mimicking the real stack, this stack lives on the heap, avoiding stack
- * overflows.
- *
- * At each recursion step, the stack items points to the commits whose
- * ancestors are to be inspected.
- */
-struct stack {
-	int nr, alloc;
-	struct stack_entry {
-		struct commit *commit;
-		struct commit_list *parents;
-	} *stack;
-};
-
-static void push_to_stack(struct commit *candidate, struct stack *stack)
-{
-	int index = stack->nr++;
-	ALLOC_GROW(stack->stack, stack->nr, stack->alloc);
-	stack->stack[index].commit = candidate;
-	stack->stack[index].parents = candidate->parents;
-}
-
-static enum contains_result contains(struct commit *candidate,
-		const struct commit_list *want)
-{
-	struct stack stack = { 0, 0, NULL };
-	int result = contains_test(candidate, want);
-
-	if (result != CONTAINS_UNKNOWN)
-		return result;
-
-	push_to_stack(candidate, &stack);
-	while (stack.nr) {
-		struct stack_entry *entry = &stack.stack[stack.nr - 1];
-		struct commit *commit = entry->commit;
-		struct commit_list *parents = entry->parents;
-
-		if (!parents) {
-			commit->object.flags |= UNINTERESTING;
-			stack.nr--;
-		}
-		/*
-		 * If we just popped the stack, parents->item has been marked,
-		 * therefore contains_test will return a meaningful 0 or 1.
-		 */
-		else switch (contains_test(parents->item, want)) {
-		case CONTAINS_YES:
-			commit->object.flags |= TMP_MARK;
-			stack.nr--;
-			break;
-		case CONTAINS_NO:
-			entry->parents = parents->next;
-			break;
-		case CONTAINS_UNKNOWN:
-			push_to_stack(parents->item, &stack);
-			break;
-		}
-	}
-	free(stack.stack);
-	return contains_test(candidate, want);
-}
-
-/*
- * Currently dupplicated in ref-filter, will eventually be removed as
- * we port tag.c to use ref-filter APIs.
- */
-static void show_tag_lines(const struct object_id *oid, int lines)
-{
-	int i;
-	unsigned long size;
-	enum object_type type;
-	char *buf, *sp, *eol;
-	size_t len;
-
-	buf = read_sha1_file(oid->hash, &type, &size);
-	if (!buf)
-		die_errno("unable to read object %s", oid_to_hex(oid));
-	if (type != OBJ_COMMIT && type != OBJ_TAG)
-		goto free_return;
-	if (!size)
-		die("an empty %s object %s?",
-		    typename(type), oid_to_hex(oid));
-
-	/* skip header */
-	sp = strstr(buf, "\n\n");
-	if (!sp)
-		goto free_return;
-
-	/* only take up to "lines" lines, and strip the signature from a tag */
-	if (type == OBJ_TAG)
-		size = parse_signature(buf, size);
-	for (i = 0, sp += 2; i < lines && sp < buf + size; i++) {
-		if (i)
-			printf("\n    ");
-		eol = memchr(sp, '\n', size - (sp - buf));
-		len = eol ? eol - sp : size - (sp - buf);
-		fwrite(sp, len, 1, stdout);
-		if (!eol)
-			break;
-		sp = eol + 1;
-	}
-free_return:
-	free(buf);
-}
-
-static void ref_array_append(struct ref_array *array, const char *refname)
-{
-	size_t len = strlen(refname);
-	struct ref_array_item *ref = xcalloc(1, sizeof(struct ref_array_item) 
+ len + 1);
-	memcpy(ref->refname, refname, len);
-	ref->refname[len] = '\0';
-	REALLOC_ARRAY(array->items, array->nr + 1);
-	array->items[array->nr++] = ref;
-}
-
-static int show_reference(const char *refname, const struct object_id *oid,
-			  int flag, void *cb_data)
-{
-	struct ref_filter_cbdata *data = cb_data;
-	struct ref_array *array = data->array;
-	struct ref_filter *filter = data->filter;
-
-	if (match_pattern(filter->name_patterns, refname)) {
-		if (filter->with_commit) {
-			struct commit *commit;
-
-			commit = lookup_commit_reference_gently(oid->hash, 1);
-			if (!commit)
-				return 0;
-			if (!contains(commit, filter->with_commit))
-				return 0;
-		}
-
-		if (filter->points_at.nr && !match_points_at(refname, oid->hash, 
&filter->points_at))
-			return 0;
-
-		if (!filter->lines) {
-			if (tag_sort)
-				ref_array_append(array, refname);
-			else
-				printf("%s\n", refname);
-			return 0;
-		}
-		printf("%-15s ", refname);
-		show_tag_lines(oid, filter->lines);
-		putchar('\n');
-	}
-
-	return 0;
-}
-
-static int sort_by_version(const void *a_, const void *b_)
-{
-	const struct ref_array_item *a = *((struct ref_array_item **)a_);
-	const struct ref_array_item *b = *((struct ref_array_item **)b_);
-	return versioncmp(a->refname, b->refname);
-}
-
-static int list_tags(struct ref_filter *filter, int sort)
+static int list_tags(struct ref_filter *filter, struct ref_sorting 
*sorting)
  {
  	struct ref_array array;
-	struct ref_filter_cbdata data;
+	char *format;
+	int i;

  	memset(&array, 0, sizeof(array));
-	data.array = &array;
-	data.filter = filter;

  	if (filter->lines == -1)
  		filter->lines = 0;

-	for_each_tag_ref(show_reference, &data);
-	if (sort) {
-		int i;
-		if ((sort & SORT_MASK) == VERCMP_SORT)
-			qsort(array.items, array.nr,
-			      sizeof(struct ref_array_item *), sort_by_version);
-		if (sort & REVERSE_SORT)
-			for (i = array.nr - 1; i >= 0; i--)
-				printf("%s\n", array.items[i]->refname);
-		else
-			for (i = 0; i < array.nr; i++)
-				printf("%s\n", array.items[i]->refname);
-		ref_array_clear(&array);
-	}
+	if (filter->lines)
+		format = "%(refname:shortalign=16)";
+	else
+		format = "%(refname:short)";
+
+	verify_ref_format(format);
+	if (!sorting)
+		sorting = ref_default_sorting();
+	filter_refs(&array, filter, FILTER_REFS_TAGS);
+	ref_array_sort(sorting, &array);
+
+	for (i = 0; i < array.nr; i++)
+		show_ref_array_item(array.items[i], format, QUOTE_NONE, filter->lines);
+	ref_array_clear(&array);
+
  	return 0;
  }

@@ -366,35 +122,23 @@ static const char tag_template_nocleanup[] =
  	"Lines starting with '%c' will be kept; you may remove them"
  	" yourself if you want to.\n");

-/*
- * Parse a sort string, and return 0 if parsed successfully. Will return
- * non-zero when the sort string does not parse into a known type. If 

var is
- * given, the error message becomes a warning and includes information 
about
- * the configuration value.
- */
-static int parse_sort_string(const char *var, const char *arg, int *sort)
+/* Parse arg given and add it the ref_sorting array */
+static int parse_sorting_string(const char *arg, struct ref_sorting 
**sorting_tail)
  {
-	int type = 0, flags = 0;
-
-	if (skip_prefix(arg, "-", &arg))
-		flags |= REVERSE_SORT;
+	struct ref_sorting *s;
+	int len;

-	if (skip_prefix(arg, "version:", &arg) || skip_prefix(arg, "v:", &arg))
-		type = VERCMP_SORT;
-	else
-		type = STRCMP_SORT;
+	s = xcalloc(1, sizeof(*s));
+	s->next = *sorting_tail;
+	*sorting_tail = s;

-	if (strcmp(arg, "refname")) {
-		if (!var)
-			return error(_("unsupported sort specification '%s'"), arg);
-		else {
-			warning(_("unsupported sort specification '%s' in variable '%s'"),
-				var, arg);
-			return -1;
-		}
-	}
+	if (*arg == '-') {
+		s->reverse = 1;
+		arg++;
+ 	}

-	*sort = (type | flags);
+	len = strlen(arg);
+	s->atom = parse_ref_filter_atom(arg, arg+len);

  	return 0;
  }

@@ -402,11 +146,12 @@ static int parse_sort_string(const char *var, 

const char *arg, int *sort)
  static int git_tag_config(const char *var, const char *value, void *cb)
  {
  	int status;
+	struct ref_sorting **sorting_tail = (struct ref_sorting **)cb;

  	if (!strcmp(var, "tag.sort")) {
  		if (!value)
  			return config_error_nonbool(var);
-		parse_sort_string(var, value, &tag_sort);
+		parse_sorting_string(value, sorting_tail);
  		return 0;
  	}

@@ -564,13 +309,6 @@ static int strbuf_check_tag_ref(struct strbuf *sb, 

const char *name)
  	return check_refname_format(sb->buf, 0);
  }

-static int parse_opt_sort(const struct option *opt, const char *arg, 
int unset)
-{
-	int *sort = opt->value;
-
-	return parse_sort_string(NULL, arg, sort);
-}
-
  int cmd_tag(int argc, const char **argv, const char *prefix)
  {
  	struct strbuf buf = STRBUF_INIT;

@@ -586,6 +324,7 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  	struct ref_transaction *transaction;
  	struct strbuf err = STRBUF_INIT;
  	struct ref_filter filter;
+	static struct ref_sorting *sorting = NULL, **sorting_tail = &sorting;
  	struct option options[] = {
  		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
  		{ OPTION_INTEGER, 'n', NULL, &filter.lines, N_("n"),

@@ -611,10 +350,8 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  		OPT_COLUMN(0, "column", &colopts, N_("show tag list in columns")),
  		OPT_CONTAINS(&filter.with_commit, N_("print only tags that contain 
the commit")),
  		OPT_WITH(&filter.with_commit, N_("print only tags that contain the 
commit")),
-		{
-			OPTION_CALLBACK, 0, "sort", &tag_sort, N_("type"), N_("sort tags"),
-			PARSE_OPT_NONEG, parse_opt_sort
-		},
+		OPT_CALLBACK(0 , "sort", sorting_tail, N_("key"),
+			     N_("field name to sort on"), &parse_opt_ref_sorting),
  		{
  			OPTION_CALLBACK, 0, "points-at", &filter.points_at, N_("object"),
  			N_("print only tags of the object"), 0, parse_opt_object_name

@@ -622,7 +359,7 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  		OPT_END()
  	};

-	git_config(git_tag_config, NULL);
+	git_config(git_tag_config, sorting_tail);

  	memset(&opt, 0, sizeof(opt));
  	memset(&filter, 0, sizeof(filter));

@@ -648,6 +385,8 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  			die(_("--column and -n are incompatible"));
  		colopts = 0;
  	}
+	if (!sorting)
+		sorting = ref_default_sorting();
  	if (cmdmode == 'l') {
  		int ret;
  		if (column_active(colopts)) {

@@ -656,10 +395,8 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  			copts.padding = 2;
  			run_column_filter(colopts, &copts);
  		}
-		if (filter.lines != -1 && tag_sort)
-			die(_("--sort and -n are incompatible"));
  		filter.name_patterns = argv;
-		ret = list_tags(&filter, tag_sort);
+		ret = list_tags(&filter, sorting);
  		if (column_active(colopts))
  			stop_column_filter();
  		return ret;

diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index d1ff5c9..51a233f 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh

@@ -1450,13 +1450,7 @@ test_expect_success 'invalid sort parameter on 

command line' '

  test_expect_success 'invalid sort parameter in configuratoin' '
  	git config tag.sort "v:notvalid" &&
-	git tag -l "foo*" >actual &&
-	cat >expect <<-\EOF &&
-	foo1.10
-	foo1.3
-	foo1.6
-	EOF
-	test_cmp expect actual
+	test_must_fail git tag -l "foo*" >actual
  '

  test_expect_success 'version sort with prerelease reordering' '
-- 
2.4.5

Make 'tag.c' use 'ref-filter' APIs for iterating through refs
sorting and printing of refs. This removes most of the code
used in 'tag.c' replacing it with calls to the 'ref-filter'
library.

Make 'tag.c' use the 'filter_refs()' function provided by
'ref-filter' to filter out tags based on the options set.

For printing tags we use 'show_ref_array_item()' function
provided by 'ref-filter'.

We improve the sorting option provided by 'tag.c' by using the
sorting options provided by 'ref-filter'. This causes the test
'invalid sort parameter on command line' in t7004 to fail, as
'ref-filter' throws an error for all sorting fields which are
incorrect. The test is changed to reflect the same.

Modify documentation for the same.

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
  Documentation/git-tag.txt |  16 ++-
  builtin/tag.c             | 343 
++++++----------------------------------------
  t/t7004-tag.sh            |   8 +-
  3 files changed, 50 insertions(+), 317 deletions(-)

diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 4b04c2b..02fb363 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt

@@ -13,7 +13,7 @@ SYNOPSIS
  	<tagname> [<commit> | <object>]
  'git tag' -d <tagname>...
  'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
-	[--column[=<options>] | --no-column] [<pattern>...]
+	[--column[=<options>] | --no-column] [--sort=<key>] [<pattern>...]
  'git tag' -v <tagname>...

  DESCRIPTION

@@ -94,14 +94,16 @@ OPTIONS
  	using fnmatch(3)).  Multiple patterns may be given; if any of
  	them matches, the tag is shown.

---sort=<type>::
-	Sort in a specific order. Supported type is "refname"
-	(lexicographic order), "version:refname" or "v:refname" (tag
+--sort=<key>::
+	Sort based on the key given.  Prefix `-` to sort in
+	descending order of the value. You may use the --sort=<key> option
+	multiple times, in which case the last key becomes the primary
+	key. Also supports "version:refname" or "v:refname" (tag
  	names are treated as versions). The "version:refname" sort
  	order can also be affected by the
-	"versionsort.prereleaseSuffix" configuration variable. Prepend
-	"-" to reverse sort order. When this option is not given, the
-	sort order defaults to the value configured for the 'tag.sort'
+	"versionsort.prereleaseSuffix" configuration variable.
+	The keys supported are the same as those in `git for-each-ref`.
+	Sort order defaults to the value configured for the 'tag.sort'
  	variable if it exists, or lexicographic order otherwise. See
  	linkgit:git-config[1].

diff --git a/builtin/tag.c b/builtin/tag.c
index bbda0c6..36f8019 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c

@@ -28,278 +28,34 @@ static const char * const git_tag_usage[] = {
  	NULL
  };

-#define STRCMP_SORT     0	/* must be zero */
-#define VERCMP_SORT     1
-#define SORT_MASK       0x7fff
-#define REVERSE_SORT    0x8000
-
-static int tag_sort;
-
  static unsigned int colopts;

-static int match_pattern(const char **patterns, const char *ref)
-{
-	/* no pattern means match everything */
-	if (!*patterns)
-		return 1;
-	for (; *patterns; patterns++)
-		if (!wildmatch(*patterns, ref, 0, NULL))
-			return 1;
-	return 0;
-}
-
-/*
- * This is currently duplicated in ref-filter.c, and will eventually be
- * removed as we port tag.c to use the ref-filter APIs.
- */
-static const unsigned char *match_points_at(const char *refname,
-					    const unsigned char *sha1,
-					    struct sha1_array *points_at)
-{
-	const unsigned char *tagged_sha1 = NULL;
-	struct object *obj;
-
-	if (sha1_array_lookup(points_at, sha1) >= 0)
-		return sha1;
-	obj = parse_object(sha1);
-	if (!obj)
-		die(_("malformed object at '%s'"), refname);
-	if (obj->type == OBJ_TAG)
-		tagged_sha1 = ((struct tag *)obj)->tagged->sha1;
-	if (tagged_sha1 && sha1_array_lookup(points_at, tagged_sha1) >= 0)
-		return tagged_sha1;
-	return NULL;
-}
-
-static int in_commit_list(const struct commit_list *want, struct commit *c)
-{
-	for (; want; want = want->next)
-		if (!hashcmp(want->item->object.sha1, c->object.sha1))
-			return 1;
-	return 0;
-}
-
-/*
- * The entire code segment for supporting the --contains option has been
- * copied over to ref-filter.{c,h}. This will be deleted evetually when
- * we port tag.c to use ref-filter APIs.
- */
-enum contains_result {
-	CONTAINS_UNKNOWN = -1,
-	CONTAINS_NO = 0,
-	CONTAINS_YES = 1
-};
-
-/*
- * Test whether the candidate or one of its parents is contained in the 

list.
- * Do not recurse to find out, though, but return -1 if inconclusive.
- */
-static enum contains_result contains_test(struct commit *candidate,
-			    const struct commit_list *want)
-{
-	/* was it previously marked as containing a want commit? */
-	if (candidate->object.flags & TMP_MARK)
-		return 1;
-	/* or marked as not possibly containing a want commit? */
-	if (candidate->object.flags & UNINTERESTING)
-		return 0;
-	/* or are we it? */
-	if (in_commit_list(want, candidate)) {
-		candidate->object.flags |= TMP_MARK;
-		return 1;
-	}
-
-	if (parse_commit(candidate) < 0)
-		return 0;
-
-	return -1;
-}
-
-/*
- * Mimicking the real stack, this stack lives on the heap, avoiding stack
- * overflows.
- *
- * At each recursion step, the stack items points to the commits whose
- * ancestors are to be inspected.
- */
-struct stack {
-	int nr, alloc;
-	struct stack_entry {
-		struct commit *commit;
-		struct commit_list *parents;
-	} *stack;
-};
-
-static void push_to_stack(struct commit *candidate, struct stack *stack)
-{
-	int index = stack->nr++;
-	ALLOC_GROW(stack->stack, stack->nr, stack->alloc);
-	stack->stack[index].commit = candidate;
-	stack->stack[index].parents = candidate->parents;
-}
-
-static enum contains_result contains(struct commit *candidate,
-		const struct commit_list *want)
-{
-	struct stack stack = { 0, 0, NULL };
-	int result = contains_test(candidate, want);
-
-	if (result != CONTAINS_UNKNOWN)
-		return result;
-
-	push_to_stack(candidate, &stack);
-	while (stack.nr) {
-		struct stack_entry *entry = &stack.stack[stack.nr - 1];
-		struct commit *commit = entry->commit;
-		struct commit_list *parents = entry->parents;
-
-		if (!parents) {
-			commit->object.flags |= UNINTERESTING;
-			stack.nr--;
-		}
-		/*
-		 * If we just popped the stack, parents->item has been marked,
-		 * therefore contains_test will return a meaningful 0 or 1.
-		 */
-		else switch (contains_test(parents->item, want)) {
-		case CONTAINS_YES:
-			commit->object.flags |= TMP_MARK;
-			stack.nr--;
-			break;
-		case CONTAINS_NO:
-			entry->parents = parents->next;
-			break;
-		case CONTAINS_UNKNOWN:
-			push_to_stack(parents->item, &stack);
-			break;
-		}
-	}
-	free(stack.stack);
-	return contains_test(candidate, want);
-}
-
-/*
- * Currently dupplicated in ref-filter, will eventually be removed as
- * we port tag.c to use ref-filter APIs.
- */
-static void show_tag_lines(const struct object_id *oid, int lines)
-{
-	int i;
-	unsigned long size;
-	enum object_type type;
-	char *buf, *sp, *eol;
-	size_t len;
-
-	buf = read_sha1_file(oid->hash, &type, &size);
-	if (!buf)
-		die_errno("unable to read object %s", oid_to_hex(oid));
-	if (type != OBJ_COMMIT && type != OBJ_TAG)
-		goto free_return;
-	if (!size)
-		die("an empty %s object %s?",
-		    typename(type), oid_to_hex(oid));
-
-	/* skip header */
-	sp = strstr(buf, "\n\n");
-	if (!sp)
-		goto free_return;
-
-	/* only take up to "lines" lines, and strip the signature from a tag */
-	if (type == OBJ_TAG)
-		size = parse_signature(buf, size);
-	for (i = 0, sp += 2; i < lines && sp < buf + size; i++) {
-		if (i)
-			printf("\n    ");
-		eol = memchr(sp, '\n', size - (sp - buf));
-		len = eol ? eol - sp : size - (sp - buf);
-		fwrite(sp, len, 1, stdout);
-		if (!eol)
-			break;
-		sp = eol + 1;
-	}
-free_return:
-	free(buf);
-}
-
-static void ref_array_append(struct ref_array *array, const char *refname)
-{
-	size_t len = strlen(refname);
-	struct ref_array_item *ref = xcalloc(1, sizeof(struct ref_array_item) 
+ len + 1);
-	memcpy(ref->refname, refname, len);
-	ref->refname[len] = '\0';
-	REALLOC_ARRAY(array->items, array->nr + 1);
-	array->items[array->nr++] = ref;
-}
-
-static int show_reference(const char *refname, const struct object_id *oid,
-			  int flag, void *cb_data)
-{
-	struct ref_filter_cbdata *data = cb_data;
-	struct ref_array *array = data->array;
-	struct ref_filter *filter = data->filter;
-
-	if (match_pattern(filter->name_patterns, refname)) {
-		if (filter->with_commit) {
-			struct commit *commit;
-
-			commit = lookup_commit_reference_gently(oid->hash, 1);
-			if (!commit)
-				return 0;
-			if (!contains(commit, filter->with_commit))
-				return 0;
-		}
-
-		if (filter->points_at.nr && !match_points_at(refname, oid->hash, 
&filter->points_at))
-			return 0;
-
-		if (!filter->lines) {
-			if (tag_sort)
-				ref_array_append(array, refname);
-			else
-				printf("%s\n", refname);
-			return 0;
-		}
-		printf("%-15s ", refname);
-		show_tag_lines(oid, filter->lines);
-		putchar('\n');
-	}
-
-	return 0;
-}
-
-static int sort_by_version(const void *a_, const void *b_)
-{
-	const struct ref_array_item *a = *((struct ref_array_item **)a_);
-	const struct ref_array_item *b = *((struct ref_array_item **)b_);
-	return versioncmp(a->refname, b->refname);
-}
-
-static int list_tags(struct ref_filter *filter, int sort)
+static int list_tags(struct ref_filter *filter, struct ref_sorting 
*sorting)
  {
  	struct ref_array array;
-	struct ref_filter_cbdata data;
+	char *format;
+	int i;

  	memset(&array, 0, sizeof(array));
-	data.array = &array;
-	data.filter = filter;

  	if (filter->lines == -1)
  		filter->lines = 0;

-	for_each_tag_ref(show_reference, &data);
-	if (sort) {
-		int i;
-		if ((sort & SORT_MASK) == VERCMP_SORT)
-			qsort(array.items, array.nr,
-			      sizeof(struct ref_array_item *), sort_by_version);
-		if (sort & REVERSE_SORT)
-			for (i = array.nr - 1; i >= 0; i--)
-				printf("%s\n", array.items[i]->refname);
-		else
-			for (i = 0; i < array.nr; i++)
-				printf("%s\n", array.items[i]->refname);
-		ref_array_clear(&array);
-	}
+	if (filter->lines)
+		format = "%(refname:shortalign=16)";
+	else
+		format = "%(refname:short)";
+
+	verify_ref_format(format);
+	if (!sorting)
+		sorting = ref_default_sorting();
+	filter_refs(&array, filter, FILTER_REFS_TAGS);
+	ref_array_sort(sorting, &array);
+
+	for (i = 0; i < array.nr; i++)
+		show_ref_array_item(array.items[i], format, QUOTE_NONE, filter->lines);
+	ref_array_clear(&array);
+
  	return 0;
  }

@@ -366,35 +122,23 @@ static const char tag_template_nocleanup[] =
  	"Lines starting with '%c' will be kept; you may remove them"
  	" yourself if you want to.\n");

-/*
- * Parse a sort string, and return 0 if parsed successfully. Will return
- * non-zero when the sort string does not parse into a known type. If 

var is
- * given, the error message becomes a warning and includes information 
about
- * the configuration value.
- */
-static int parse_sort_string(const char *var, const char *arg, int *sort)
+/* Parse arg given and add it the ref_sorting array */
+static int parse_sorting_string(const char *arg, struct ref_sorting 
**sorting_tail)
  {
-	int type = 0, flags = 0;
-
-	if (skip_prefix(arg, "-", &arg))
-		flags |= REVERSE_SORT;
+	struct ref_sorting *s;
+	int len;

-	if (skip_prefix(arg, "version:", &arg) || skip_prefix(arg, "v:", &arg))
-		type = VERCMP_SORT;
-	else
-		type = STRCMP_SORT;
+	s = xcalloc(1, sizeof(*s));
+	s->next = *sorting_tail;
+	*sorting_tail = s;

-	if (strcmp(arg, "refname")) {
-		if (!var)
-			return error(_("unsupported sort specification '%s'"), arg);
-		else {
-			warning(_("unsupported sort specification '%s' in variable '%s'"),
-				var, arg);
-			return -1;
-		}
-	}
+	if (*arg == '-') {
+		s->reverse = 1;
+		arg++;
+ 	}

-	*sort = (type | flags);
+	len = strlen(arg);
+	s->atom = parse_ref_filter_atom(arg, arg+len);

  	return 0;
  }

@@ -402,11 +146,12 @@ static int parse_sort_string(const char *var, 

const char *arg, int *sort)
  static int git_tag_config(const char *var, const char *value, void *cb)
  {
  	int status;
+	struct ref_sorting **sorting_tail = (struct ref_sorting **)cb;

  	if (!strcmp(var, "tag.sort")) {
  		if (!value)
  			return config_error_nonbool(var);
-		parse_sort_string(var, value, &tag_sort);
+		parse_sorting_string(value, sorting_tail);
  		return 0;
  	}

@@ -564,13 +309,6 @@ static int strbuf_check_tag_ref(struct strbuf *sb, 

const char *name)
  	return check_refname_format(sb->buf, 0);
  }

-static int parse_opt_sort(const struct option *opt, const char *arg, 
int unset)
-{
-	int *sort = opt->value;
-
-	return parse_sort_string(NULL, arg, sort);
-}
-
  int cmd_tag(int argc, const char **argv, const char *prefix)
  {
  	struct strbuf buf = STRBUF_INIT;

@@ -586,6 +324,7 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  	struct ref_transaction *transaction;
  	struct strbuf err = STRBUF_INIT;
  	struct ref_filter filter;
+	static struct ref_sorting *sorting = NULL, **sorting_tail = &sorting;
  	struct option options[] = {
  		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
  		{ OPTION_INTEGER, 'n', NULL, &filter.lines, N_("n"),

@@ -611,10 +350,8 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  		OPT_COLUMN(0, "column", &colopts, N_("show tag list in columns")),
  		OPT_CONTAINS(&filter.with_commit, N_("print only tags that contain 
the commit")),
  		OPT_WITH(&filter.with_commit, N_("print only tags that contain the 
commit")),
-		{
-			OPTION_CALLBACK, 0, "sort", &tag_sort, N_("type"), N_("sort tags"),
-			PARSE_OPT_NONEG, parse_opt_sort
-		},
+		OPT_CALLBACK(0 , "sort", sorting_tail, N_("key"),
+			     N_("field name to sort on"), &parse_opt_ref_sorting),
  		{
  			OPTION_CALLBACK, 0, "points-at", &filter.points_at, N_("object"),
  			N_("print only tags of the object"), 0, parse_opt_object_name

@@ -622,7 +359,7 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  		OPT_END()
  	};

-	git_config(git_tag_config, NULL);
+	git_config(git_tag_config, sorting_tail);

  	memset(&opt, 0, sizeof(opt));
  	memset(&filter, 0, sizeof(filter));

@@ -648,6 +385,8 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  			die(_("--column and -n are incompatible"));
  		colopts = 0;
  	}
+	if (!sorting)
+		sorting = ref_default_sorting();
  	if (cmdmode == 'l') {
  		int ret;
  		if (column_active(colopts)) {

@@ -656,10 +395,8 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  			copts.padding = 2;
  			run_column_filter(colopts, &copts);
  		}
-		if (filter.lines != -1 && tag_sort)
-			die(_("--sort and -n are incompatible"));
  		filter.name_patterns = argv;
-		ret = list_tags(&filter, tag_sort);
+		ret = list_tags(&filter, sorting);
  		if (column_active(colopts))
  			stop_column_filter();
  		return ret;

diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index d1ff5c9..51a233f 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh

@@ -1450,13 +1450,7 @@ test_expect_success 'invalid sort parameter on 

command line' '

  test_expect_success 'invalid sort parameter in configuratoin' '
  	git config tag.sort "v:notvalid" &&
-	git tag -l "foo*" >actual &&
-	cat >expect <<-\EOF &&
-	foo1.10
-	foo1.3
-	foo1.6
-	EOF
-	test_cmp expect actual
+	test_must_fail git tag -l "foo*" >actual
  '

  test_expect_success 'version sort with prerelease reordering' '
-- 
2.4.5

Implement the '--format' option provided by 'ref-filter'.
This lets the user list tags as per desired format similar
to the implementation in 'git for-each-ref'.

Add tests and documentation for the same.

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
  Documentation/git-tag.txt | 16 +++++++++++++++-
  builtin/tag.c             | 11 +++++++----
  t/t7004-tag.sh            | 16 ++++++++++++++++
  3 files changed, 38 insertions(+), 5 deletions(-)

diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 02fb363..16e396c 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt

@@ -13,7 +13,8 @@ SYNOPSIS
  	<tagname> [<commit> | <object>]
  'git tag' -d <tagname>...
  'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
-	[--column[=<options>] | --no-column] [--sort=<key>] [<pattern>...]
+	[--column[=<options>] | --no-column] [--sort=<key>] [--format=<format>]
+	[<pattern>...]
  'git tag' -v <tagname>...

  DESCRIPTION

@@ -155,6 +156,19 @@ This option is only applicable when listing tags 

without annotation lines.
  	The object that the new tag will refer to, usually a commit.
  	Defaults to HEAD.

+<format>::
+	A string that interpolates `%(fieldname)` from the
+	object pointed at by a ref being shown.  If `fieldname`
+	is prefixed with an asterisk (`*`) and the ref points
+	at a tag object, the value for the field in the object
+	tag refers is used.  When unspecified, defaults to
+	`%(objectname) SPC %(objecttype) TAB %(refname)`.
+	It also interpolates `%%` to `%`, and `%xx` where `xx`
+	are hex digits interpolates to character with hex code
+	`xx`; for example `%00` interpolates to `\0` (NUL),
+	`%09` to `\t` (TAB) and `%0a` to `\n` (LF).
+	The fields are same as those in `git for-each-ref`.
+

  CONFIGURATION
  -------------

diff --git a/builtin/tag.c b/builtin/tag.c
index 36f8019..601b293 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c

@@ -30,10 +30,9 @@ static const char * const git_tag_usage[] = {

  static unsigned int colopts;

-static int list_tags(struct ref_filter *filter, struct ref_sorting 

*sorting)
+static int list_tags(struct ref_filter *filter, struct ref_sorting 
*sorting, const char *format)
  {
  	struct ref_array array;
-	char *format;
  	int i;

  	memset(&array, 0, sizeof(array));

@@ -43,7 +42,7 @@ static int list_tags(struct ref_filter *filter, struct 

ref_sorting *sorting)

  	if (filter->lines)
  		format = "%(refname:shortalign=16)";
-	else
+	else if (!format)
  		format = "%(refname:short)";

  	verify_ref_format(format);

@@ -325,6 +324,7 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  	struct strbuf err = STRBUF_INIT;
  	struct ref_filter filter;
  	static struct ref_sorting *sorting = NULL, **sorting_tail = &sorting;
+	const char *format = NULL;
  	struct option options[] = {
  		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
  		{ OPTION_INTEGER, 'n', NULL, &filter.lines, N_("n"),

@@ -356,6 +356,7 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  			OPTION_CALLBACK, 0, "points-at", &filter.points_at, N_("object"),
  			N_("print only tags of the object"), 0, parse_opt_object_name
  		},
+		OPT_STRING(  0 , "format", &format, N_("format"), N_("format to use 
for the output")),
  		OPT_END()
  	};

@@ -395,8 +396,10 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  			copts.padding = 2;
  			run_column_filter(colopts, &copts);
  		}
+		if (format && (filter.lines != -1))
+			die(_("--format and -n are incompatible"));
  		filter.name_patterns = argv;
-		ret = list_tags(&filter, sorting);
+		ret = list_tags(&filter, sorting, format);
  		if (column_active(colopts))
  			stop_column_filter();
  		return ret;

diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index 51a233f..e8cebb6 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh

@@ -1507,4 +1507,20 @@ EOF"
  	test_cmp expect actual
  '

+test_expect_success '--format cannot be used with -n' '
+	test_must_fail git tag -l -n4 --format="%(refname)"
+'
+
+test_expect_success '--format should list tags as per format given' '
+	cat >expect <<-\EOF &&
+	foo1.10
+	foo1.3
+	foo1.6
+	foo1.6-rc1
+	foo1.6-rc2
+	EOF
+	git tag -l --format="%(refname)" "foo*" >actual &&
+	test_cmp expect actual
+'
+
  test_done

-- 
2.4.5

Using 'ref-filter' APIs implement the '--merged' and '--no-merged'
options into 'tag.c'. The '--merged' option lets the user to only
list tags merged into the named commit. The '--no-merged' option
lets the user to only list tags not merged into the named commit.
If no object is provided it assumes HEAD as the object.

Add documentation and tests for the same.

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
  Documentation/git-tag.txt | 10 +++++++++-
  builtin/tag.c             |  6 +++++-
  t/t7004-tag.sh            | 27 +++++++++++++++++++++++++++
  3 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 16e396c..74ed157 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt

@@ -14,7 +14,7 @@ SYNOPSIS
  'git tag' -d <tagname>...
  'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
  	[--column[=<options>] | --no-column] [--sort=<key>] [--format=<format>]
-	[<pattern>...]
+	[(--merged | --no-merged) [<commit>]] [<pattern>...]
  'git tag' -v <tagname>...

  DESCRIPTION

@@ -169,6 +169,14 @@ This option is only applicable when listing tags 

without annotation lines.
  	`%09` to `\t` (TAB) and `%0a` to `\n` (LF).
  	The fields are same as those in `git for-each-ref`.

+--merged [<commit>]::
+	Only list tags whose tips are reachable from the
+	specified commit (HEAD if not specified).
+
+--no-merged [<commit>]::
+	Only list tags whose tips are not reachable from the
+	specified commit (HEAD if not specified).
+

  CONFIGURATION
  -------------

diff --git a/builtin/tag.c b/builtin/tag.c
index 601b293..abd42a0 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c

@@ -23,7 +23,7 @@ static const char * const git_tag_usage[] = {
  	N_("git tag [-a | -s | -u <key-id>] [-f] [-m <msg> | -F <file>] 

<tagname> [<head>]"),
  	N_("git tag -d <tagname>..."),
  	N_("git tag -l [-n[<num>]] [--contains <commit>] [--points-at <object>]"
-		"\n\t\t[<pattern>...]"),
+		"\n\t\t[--merged [<commit>]] [--no-merged [<commit>]] [<pattern>...]"),
  	N_("git tag -v <tagname>..."),
  	NULL
  };

@@ -350,6 +350,8 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  		OPT_COLUMN(0, "column", &colopts, N_("show tag list in columns")),
  		OPT_CONTAINS(&filter.with_commit, N_("print only tags that contain 
the commit")),
  		OPT_WITH(&filter.with_commit, N_("print only tags that contain the 
commit")),
+		OPT_MERGED(&filter, N_("print only tags that are merged")),
+		OPT_NO_MERGED(&filter, N_("print only tags that are not merged")),
  		OPT_CALLBACK(0 , "sort", sorting_tail, N_("key"),
  			     N_("field name to sort on"), &parse_opt_ref_sorting),
  		{

@@ -410,6 +412,8 @@ int cmd_tag(int argc, const char **argv, const char 

*prefix)
  		die(_("--contains option is only allowed with -l."));
  	if (filter.points_at.nr)
  		die(_("--points-at option is only allowed with -l."));
+	if (filter.merge_commit)
+		die(_("--merged and --no-merged option are only allowed with -l"));
  	if (cmdmode == 'd')
  		return for_each_tag_name(argv, delete_tag);
  	if (cmdmode == 'v')

diff --git a/t/t7004-tag.sh b/t/t7004-tag.sh
index e8cebb6..873aad3 100755
--- a/t/t7004-tag.sh
+++ b/t/t7004-tag.sh

@@ -1523,4 +1523,31 @@ test_expect_success '--format should list tags as 

per format given' '
  	test_cmp expect actual
  '

+test_expect_success 'setup --merged test tags' '
+	git tag mergetest-1 HEAD~2 &&
+	git tag mergetest-2 HEAD~1 &&
+	git tag mergetest-3 HEAD
+'
+
+test_expect_success '--merged cannot be used in non-list mode' '
+	test_must_fail git tag --merged=mergetest-2 foo
+'
+
+test_expect_success '--merged shows merged tags' '
+	cat >expect <<-\EOF &&
+	mergetest-1
+	mergetest-2
+	EOF
+	git tag -l --merged=mergetest-2 mergetest-* >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--no-merged show unmerged tags' '
+	cat >expect <<-\EOF &&
+	mergetest-3
+	EOF
+	git tag -l --no-merged=mergetest-2 mergetest-* >actual &&
+	test_cmp expect actual
+'
+
  test_done
-- 
2.4.5

On Thu, Jul 9, 2015 at 12:27 PM, Karthik Nayak [off-list ref] wrote:

As this patch could be applied directly to master and to maint maybe
you could send it at the top of this patch series or alone outside of
this patch series.

On Thu, Jul 9, 2015 at 5:49 PM, Christian Couder
[off-list ref] wrote:

On Thu, Jul 9, 2015 at 12:27 PM, Karthik Nayak [off-list ref] wrote:

quoted

Mentored-by: Christian Couder [off-list ref]
Mentored-by: Matthieu Moy [off-list ref]
Signed-off-by: Karthik Nayak <redacted>
---
 Documentation/git-tag.txt | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Documentation/git-tag.txt b/Documentation/git-tag.txt
index 034d10d..4b04c2b 100644
--- a/Documentation/git-tag.txt
+++ b/Documentation/git-tag.txt

@@ -14,7 +14,6 @@ SYNOPSIS
 'git tag' -d <tagname>...
 'git tag' [-n[<num>]] -l [--contains <commit>] [--points-at <object>]
        [--column[=<options>] | --no-column] [<pattern>...]
-       [<pattern>...]
 'git tag' -v <tagname>...

As this patch could be applied directly to master and to maint maybe
you could send it at the top of this patch series or alone outside of
this patch series.

I'll do that :)

-- 
Regards,
Karthik Nayak

On Thu, Jul 9, 2015 at 5:58 PM, Karthik Nayak [off-list ref] wrote:

-static int show_reference(const char *refname, const struct object_id *oid,
-                         int flag, void *cb_data)
-{

...

-
-       if (match_pattern(filter->name_patterns, refname)) {

....

-               printf("%-15s ", refname);
-               show_tag_lines(oid, filter->lines);
-               putchar('\n');
-       }
-
-       return 0;
-}

...

+       if (filter->lines)
+               format = "%(refname:shortalign=16)";
+       else
+               format = "%(refname:short)";

I can see this is a faithful conversion, but this looks line an
opportunity to avoid this special limit 15/16. Even on git.git "git
tag -l -n1" already breaks alignment with *.msysgit.* tags (ok maybe
msysgit, not purely git.git) When you get to "branch -l", it
calculates the max-width automatically so you probably need
"%(refname:shortalign)" any way. "shortalign" (i.e. create the "align"
version for every modifier) does not look good because it could double
the number of modifiers and let's not thinking about truncation
options or right alignment..
-- 
Duy

On Sun, Jul 12, 2015 at 3:15 PM, Duy Nguyen [off-list ref] wrote:

On Thu, Jul 9, 2015 at 5:58 PM, Karthik Nayak [off-list ref] wrote:

quoted

-static int show_reference(const char *refname, const struct object_id *oid,
-                         int flag, void *cb_data)
-{

...

quoted

-
-       if (match_pattern(filter->name_patterns, refname)) {

....

quoted

-               printf("%-15s ", refname);
-               show_tag_lines(oid, filter->lines);
-               putchar('\n');
-       }
-
-       return 0;
-}

...

quoted

+       if (filter->lines)
+               format = "%(refname:shortalign=16)";
+       else
+               format = "%(refname:short)";

I can see this is a faithful conversion, but this looks line an
opportunity to avoid this special limit 15/16. Even on git.git "git
tag -l -n1" already breaks alignment with *.msysgit.* tags (ok maybe
msysgit, not purely git.git) When you get to "branch -l", it
calculates the max-width automatically so you probably need
"%(refname:shortalign)" any way. "shortalign" (i.e. create the "align"
version for every modifier) does not look good because it could double
the number of modifiers and let's not thinking about truncation
options or right alignment..

What I was thinking of was getting rid of the whole "align" feature where
you provide a value to which it would align.

Something like:  --format="%(item:modifieralign)" which would use something
on the lines of what the max-width calculator in branch -l uses, to get the max
alignment size. But the problem is that ref-filter goes through the refs using
a function which has no connections with the atoms used. So a more practical
solution would be --format="%(item:modifieralign=X)" where we could provide a
means of calculating X via ref-filter. Something like this in tag.c:

int max_width = get_max_width("<item to get max_width of>");
use this max_width to then do a
--format="%(item:modifieralign=X)", where X = max_width

What do you think?

-- 
Regards,
Karthik Nayak

On Mon, Jul 13, 2015 at 2:36 AM, Karthik Nayak [off-list ref] wrote:

What I was thinking of was getting rid of the whole "align" feature where
you provide a value to which it would align.

Something like:  --format="%(item:modifieralign)" which would use something
on the lines of what the max-width calculator in branch -l uses, to get the max
alignment size. But the problem is that ref-filter goes through the refs using
a function which has no connections with the atoms used. So a more practical
solution would be --format="%(item:modifieralign=X)" where we could provide a
means of calculating X via ref-filter. Something like this in tag.c:

int max_width = get_max_width("<item to get max_width of>");
use this max_width to then do a
--format="%(item:modifieralign=X)", where X = max_width

What do you think?

This is where separate "alignment atoms" (instead of alignment
modifiers) make sense. Suppose you introduce another function, let's
say print_all() for now, to wrap the "for (i < maxcount)" loop at the
end of for-each-ref, you would have total control over display and
formatting. populate_value() generates empty strings for these
alignment atoms (because they don't really have true values). Those
alignment atoms are recognized in print_all() and
show_ref_array_item(). In print_all(), if it sees max width needs to
be calculated (because the user does not specify the width), it can
call populate_value() for an atom for all rows. show_ref_array_item()
does the padding and even truncating if needed. This pattern is
similar to how print_columns() works, first we collect data of the
whole "table", then we place them line by line.

It sounds good to me. But it may not be the best option, I don't know.
And it may create unnecessary work. So you and your mentors decide.
-- 
Duy

On Mon, Jul 13, 2015 at 4:16 PM, Duy Nguyen [off-list ref] wrote:

On Mon, Jul 13, 2015 at 2:36 AM, Karthik Nayak [off-list ref] wrote:

quoted

What I was thinking of was getting rid of the whole "align" feature where
you provide a value to which it would align.

Something like:  --format="%(item:modifieralign)" which would use something
on the lines of what the max-width calculator in branch -l uses, to get the max
alignment size. But the problem is that ref-filter goes through the refs using
a function which has no connections with the atoms used. So a more practical
solution would be --format="%(item:modifieralign=X)" where we could provide a
means of calculating X via ref-filter. Something like this in tag.c:

int max_width = get_max_width("<item to get max_width of>");
use this max_width to then do a
--format="%(item:modifieralign=X)", where X = max_width

What do you think?

This is where separate "alignment atoms" (instead of alignment
modifiers) make sense. Suppose you introduce another function, let's
say print_all() for now, to wrap the "for (i < maxcount)" loop at the
end of for-each-ref, you would have total control over display and
formatting. populate_value() generates empty strings for these
alignment atoms (because they don't really have true values). Those
alignment atoms are recognized in print_all() and
show_ref_array_item(). In print_all(), if it sees max width needs to
be calculated (because the user does not specify the width), it can
call populate_value() for an atom for all rows. show_ref_array_item()
does the padding and even truncating if needed. This pattern is
similar to how print_columns() works, first we collect data of the
whole "table", then we place them line by line.

It sounds good to me. But it may not be the best option, I don't know.
And it may create unnecessary work. So you and your mentors decide.
--
Duy

Sounds good, but what you're saying goes on the lines of interdependence of
atoms, since we would have separate atoms. Not sure we want to do that right
now.

-- 
Regards,
Karthik Nayak