branch: honor --abbrev/--no-abbrev in --list mode

When the "branch --list" command was converted to use the --format
facility from the ref-filter API, we forgot to honor the --abbrev
setting in the default output format and instead used a hardcoded
"7".

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/branch.c

@@ -335,9 +335,18 @@ static char *build_format(struct ref_filter *filter, int maxwidth, const char *r
 		    branch_get_color(BRANCH_COLOR_CURRENT));
 
 	if (filter->verbose) {
+		struct strbuf obname = STRBUF_INIT;
+
+		if (filter->abbrev < 0)
+			strbuf_addf(&obname, "%%(objectname:short)");
+		else if (!filter->abbrev)
+			strbuf_addf(&obname, "%%(objectname)");
+		else
+			strbuf_addf(&obname, "%%(objectname:short=%d)", filter->abbrev);
+
 		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) ");
+		strbuf_addf(&local, " %s ", obname.buf);
 
 		if (filter->verbose > 1)
 			strbuf_addf(&local, "%%(if)%%(upstream)%%(then)[%s%%(upstream:short)%s%%(if)%%(upstream:track)"
@@ -346,10 +355,12 @@ static char *build_format(struct ref_filter *filter, int maxwidth, const char *r
 		else
 			strbuf_addf(&local, "%%(if)%%(upstream:track)%%(then)%%(upstream:track) %%(end)%%(contents:subject)");
 
-		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)",
+		strbuf_addf(&remote, "%s%%(align:%d,left)%s%%(refname:lstrip=2)%%(end)%s"
+			    "%%(if)%%(symref)%%(then) -> %%(symref:short)"
+			    "%%(else) %s %%(contents:subject)%%(end)",
 			    branch_get_color(BRANCH_COLOR_REMOTE), maxwidth, quote_literal_for_format(remote_prefix),
-			    branch_get_color(BRANCH_COLOR_RESET));
+			    branch_get_color(BRANCH_COLOR_RESET), obname.buf);
+		strbuf_release(&obname);
 	} else {
 		strbuf_addf(&local, "%%(refname:lstrip=2)%s%%(if)%%(symref)%%(then) -> %%(symref:short)%%(end)",
 			    branch_get_color(BRANCH_COLOR_RESET));

t/t3200-branch.sh

@@ -207,6 +207,31 @@ test_expect_success 'git branch --list -d t should fail' '
 	test_path_is_missing .git/refs/heads/t
 '
 
+test_expect_success 'git branch --list -v with --abbrev' '
+	test_when_finished "git branch -D t" &&
+	git branch t &&
+	git branch -v --list t >actual.default &&
+	git branch -v --list --abbrev t >actual.abbrev &&
+	test_cmp actual.default actual.abbrev &&
+
+	git branch -v --list --no-abbrev t >actual.noabbrev &&
+	git branch -v --list --abbrev=0 t >actual.0abbrev &&
+	test_cmp actual.noabbrev actual.0abbrev &&
+
+	git branch -v --list --abbrev=36 t >actual.36abbrev &&
+	# how many hexdigits are used?
+	read name objdefault rest <actual.abbrev &&
+	read name obj36 rest <actual.36abbrev &&
+	objfull=$(git rev-parse --verify t) &&
+
+	# are we really getting abbreviations?
+	test "$obj36" != "$objdefault" &&
+	expr "$obj36" : "$objdefault" >/dev/null &&
+	test "$objfull" != "$obj36" &&
+	expr "$objfull" : "$obj36" >/dev/null
+
+'
+
 test_expect_success 'git branch --column' '
 	COLUMNS=81 git branch --column=column >actual &&
 	cat >expected <<\EOF &&