[PATCH 1/2] fetch: add a failing test for prunning with overlapping refspecs

["Carlos Martín Nieto" <cmn@elego.de>]

From: Carlos Martín Nieto <cmn@dwim.me>

When a remote has multiple fetch refspecs and these overlap in the
target namespace, fetch may prune a remote-tracking branch which still
exists in the remote. The test uses a popular form of this, by putting
pull requests as stored in a popular hosting platform alongside "real"
remote-tracking branches.

The fetch command makes a decision of whether to prune based
on the first matching refspec, which in this case is insufficient, as it
covers the pull request names. This pair of refspecs does work as
expected if the more "specific" refspec is the first in the list.

Signed-off-by: Carlos Martín Nieto <cmn@elego.de>
---

This setup is used by GitHub for Windows, but nobody has noticed this
break because it puts the PR refspec in the system config, which makes
that one the first. I was alerted to this by someone who had done this
setup manually and thus added the PR refspec after the default one.

 t/t5510-fetch.sh | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index 1f0f8e6..4949e3d 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -113,6 +113,26 @@ test_expect_success 'fetch --prune with a namespace keeps other namespaces' '
 	git rev-parse origin/master
 '
 
+test_expect_failure 'fetch --prune handles overlapping refspecs' '
+	cd "$D" &&
+	git update-ref refs/pull/42/head master &&
+	git clone . prune-overlapping &&
+	cd prune-overlapping &&
+	git config --add remote.origin.fetch refs/pull/*/head:refs/remotes/origin/pr/* &&
+
+	git fetch --prune origin &&
+	git rev-parse origin/master &&
+	git rev-parse origin/pr/42 &&
+
+	git config --unset-all remote.origin.fetch
+	git config remote.origin.fetch refs/pull/*/head:refs/remotes/origin/pr/* &&
+	git config --add remote.origin.fetch refs/heads/*:refs/remotes/origin/* &&
+
+	git fetch --prune origin &&
+	git rev-parse origin/master &&
+	git rev-parse origin/pr/42
+'
+
 test_expect_success 'fetch --prune --tags does not delete the remote-tracking branches' '
 	cd "$D" &&
 	git clone . prune-tags &&
-- 
1.9.0.rc3.244.g3497008