test_cmp expect actual
'
+. "$TEST_DIRECTORY"/lib-httpd.sh
+start_httpd
+
+REPO="$HTTPD_DOCUMENT_ROOT_PATH/repo"
+
+test_expect_success 'shallow fetches check connectivity before writing shallow file' '
+ rm -rf "$REPO" client &&
+
+ git init "$REPO" &&
+ test_commit -C "$REPO" one &&
+ test_commit -C "$REPO" two &&
+ test_commit -C "$REPO" three &&
+
+ git init client &&
+
+ # Use protocol v2 to ensure that shallow information is sent exactly
+ # once by the server, since we are planning to manipulate it.
+ git -C "$REPO" config protocol.version 2 &&
+ git -C client config protocol.version 2 &&
+
+ git -C client fetch --depth=2 "$HTTPD_URL/one_time_sed/repo" master:a_branch &&
+
+ # Craft a situation in which the server sends back an unshallow request
+ # with an empty packfile. This is done by refetching with a shorter
+ # depth (to ensure that the packfile is empty), and overwriting the
+ # shallow line in the response with the unshallow line we want.
+ printf "s/0034shallow %s/0036unshallow %s/" \
+ "$(git -C "$REPO" rev-parse HEAD)" \
+ "$(git -C "$REPO" rev-parse HEAD^)" \
+ >"$HTTPD_ROOT_PATH/one-time-sed" &&
+ test_must_fail git -C client fetch --depth=1 "$HTTPD_URL/one_time_sed/repo" \
+ master:a_branch &&
+
+ # Ensure that the one-time-sed script was used.
+ ! test -e "$HTTPD_ROOT_PATH/one-time-sed" &&
+
+ # Ensure that the resulting repo is consistent, despite our failure to
+ # fetch.
+ git -C client fsck
+'
+
+stop_httpd
+
test_done