[PATCH 2/5] ref-filter: add `short` option for 'tree' and 'parent'

["Hariom Verma via GitGitGadget" <gitgitgadget@gmail.com>]

From: Hariom Verma <hariom18599@gmail.com>

Sometimes while using 'parent' and 'tree' atom, user might
want to see abbrev hash instead of full 40 character hash.

'objectname' and 'refname' already supports printing abbrev hash.
It might be convenient for users to have the same option for printing
'parent' and 'tree' hash.

Let's introduce `short` option to 'parent' and 'tree' atom.

`tree:short` - for abbrev tree hash
`parent:short` - for abbrev parent hash

Mentored-by: Christian Couder <chriscool@tuxfamily.org>
Mentored-by: Heba Waly <heba.waly@gmail.com>
Signed-off-by: Hariom Verma <hariom18599@gmail.com>
---
 ref-filter.c            | 12 ++++++++----
 t/t6300-for-each-ref.sh |  4 ++++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/ref-filter.c b/ref-filter.c
index 8563088eb1..d5d5ff6a9d 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -983,21 +983,25 @@ static void grab_commit_values(struct atom_value *val, int deref, struct object
 			continue;
 		if (deref)
 			name++;
-		if (!strcmp(name, "tree")) {
+		if (!strcmp(name, "tree"))
 			v->s = xstrdup(oid_to_hex(get_commit_tree_oid(commit)));
-		}
+		else if (!strcmp(name, "tree:short"))
+			v->s = xstrdup(find_unique_abbrev(get_commit_tree_oid(commit), DEFAULT_ABBREV));
 		else if (!strcmp(name, "numparent")) {
 			v->value = commit_list_count(commit->parents);
 			v->s = xstrfmt("%lu", (unsigned long)v->value);
 		}
-		else if (!strcmp(name, "parent")) {
+		else if (starts_with(name, "parent")) {
 			struct commit_list *parents;
 			struct strbuf s = STRBUF_INIT;
 			for (parents = commit->parents; parents; parents = parents->next) {
 				struct commit *parent = parents->item;
 				if (parents != commit->parents)
 					strbuf_addch(&s, ' ');
-				strbuf_addstr(&s, oid_to_hex(&parent->object.oid));
+				if (!strcmp(name, "parent"))
+					strbuf_addstr(&s, oid_to_hex(&parent->object.oid));
+				else if (!strcmp(name, "parent:short"))
+					strbuf_add_unique_abbrev(&s, &parent->object.oid, DEFAULT_ABBREV);
 			}
 			v->s = strbuf_detach(&s, NULL);
 		}
diff --git a/t/t6300-for-each-ref.sh b/t/t6300-for-each-ref.sh
index b8a2cb8439..533827d297 100755
--- a/t/t6300-for-each-ref.sh
+++ b/t/t6300-for-each-ref.sh
@@ -97,7 +97,9 @@ 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 tree:short $(git rev-parse --short refs/heads/master^{tree})
 test_atom head parent ''
+test_atom head parent:short ''
 test_atom head numparent 0
 test_atom head object ''
 test_atom head type ''
@@ -148,7 +150,9 @@ 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 tree:short ''
 test_atom tag parent ''
+test_atom tag parent:short ''
 test_atom tag numparent ''
 test_atom tag object $(git rev-parse refs/tags/testtag^0)
 test_atom tag type 'commit'
-- 
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