t5500: add tests of fetch-pack --all --depth=N $URL $REF

Document some bugs in "git fetch-pack":

1. If "git fetch-pack" is called with "--all", "--depth", and an
explicit existing non-tag reference to fetch, then it falsely reports
that the reference was not found, even though it was fetched
correctly.

2. If "git fetch-pack" is called with "--all", "--depth", and an
explicit existing tag reference to fetch, then it segfaults in
filter_refs() because return_refs is used without having been
initialized.

Signed-off-by: Michael Haggerty <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: mhagger

t/t5500-fetch-pack.sh

@@ -427,4 +427,19 @@ test_expect_success 'test missing ref before existing' '
 	test_cmp expect-error error-me
 '
 
+test_expect_failure 'test --all, --depth, and explicit head' '
+	(
+		cd client &&
+		git fetch-pack --no-progress --all --depth=1 .. refs/heads/A
+	) >out-adh 2>error-adh
+'
+
+test_expect_failure 'test --all, --depth, and explicit tag' '
+	git tag OLDTAG refs/heads/B~5 &&
+	(
+		cd client &&
+		git fetch-pack --no-progress --all --depth=1 .. refs/tags/OLDTAG
+	) >out-adt 2>error-adt
+'
+
 test_done