fetch: reduce duplicate in ref update status lines with placeholder

In the "remote -> local" line, if either ref is a substring of the
other, the common part in the other string is replaced with "*". For
example

    abc                -> origin/abc
    refs/pull/123/head -> pull/123

become

    abc         -> origin/*
    refs/*/head -> pull/123

Activated with fetch.output=compact.

For the record, this output is not perfect. A single giant ref can
push all refs very far to the right and likely be wrapped around. We
may have a few options:

 - exclude these long lines smarter

 - break the line after "->", exclude it from column width calculation

 - implement a new format, { -> origin/}foo, which makes the problem
   go away at the cost of a bit harder to read

 - reverse all the arrows so we have "* <- looong-ref", again still
   hard to read.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 16 insertions, 1 deletions

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index f50497eaa..603277655 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -693,7 +693,7 @@ test_expect_success 'fetch aligned output' '
 	test_commit looooooooooooong-tag &&
 	(
 		cd full-output &&
-		git fetch origin 2>&1 | \
+		git -c fetch.output=full fetch origin 2>&1 | \
 			grep -e "->" | cut -c 22- >../actual
 	) &&
 	cat >expect <<-\EOF &&
@@ -703,4 +703,19 @@ test_expect_success 'fetch aligned output' '
 	test_cmp expect actual
 '
 
+test_expect_success 'fetch compact output' '
+	git clone . compact &&
+	test_commit extraaa &&
+	(
+		cd compact &&
+		git -c fetch.output=compact fetch origin 2>&1 | \
+			grep -e "->" | cut -c 22- >../actual
+	) &&
+	cat >expect <<-\EOF &&
+	master     -> origin/*
+	extraaa    -> *
+	EOF
+	test_cmp expect actual
+'
+
 test_done