Fix xref compile hook on deps

If xref analysis is being run by a dependency during its compilation
phase, the xref provider will try to add that deps' parents to the check
job while the ebin/ directories for them do not exist. This causes a
crash.

This patch makes it so directories are only added if they are existing,
preventing failure on any compile hook for dependencies and allowing
successful compilation as a best effort.

4 files changed, 89 insertions, 0 deletions

diff --git a/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/rebar.config b/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/rebar.config
new file mode 100644
index 0000000..cf48edf
--- /dev/null
+++ b/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/rebar.config
@@ -0,0 +1,12 @@
+{erl_opts, [debug_info]}.
+{deps, []}.
+
+{xref_checks,[
+    undefined_function_calls,
+    undefined_functions,
+    locals_not_used,
+    deprecated_function_calls,
+    deprecated_functions
+]}.
+
+{provider_hooks, [{post, [{compile, xref}]}]}.
diff --git a/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1.app.src b/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1.app.src
new file mode 100644
index 0000000..b935082
--- /dev/null
+++ b/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1.app.src
@@ -0,0 +1,16 @@
+{application, rebar_issue1,
+ [{description, "An OTP application"},
+  {vsn, "0.1.0"},
+  {registered, []},
+  {mod, { rebar_issue1_app, []}},
+  {applications,
+   [kernel,
+    stdlib
+   ]},
+  {env,[]},
+  {modules, []},
+
+  {maintainers, []},
+  {licenses, []},
+  {links, []}
+ ]}.
diff --git a/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1_app.erl b/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1_app.erl
new file mode 100644
index 0000000..78c88c1
--- /dev/null
+++ b/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1_app.erl
@@ -0,0 +1,26 @@
+%%%-------------------------------------------------------------------
+%% @doc rebar_issue1 public API
+%% @end
+%%%-------------------------------------------------------------------
+
+-module(rebar_issue1_app).
+
+-behaviour(application).
+
+%% Application callbacks
+-export([start/2, stop/1]).
+
+%%====================================================================
+%% API
+%%====================================================================
+
+start(_StartType, _StartArgs) ->
+    rebar_issue1_sup:start_link().
+
+%%--------------------------------------------------------------------
+stop(_State) ->
+    ok.
+
+%%====================================================================
+%% Internal functions
+%%====================================================================
diff --git a/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1_sup.erl b/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1_sup.erl
new file mode 100644
index 0000000..6e5a9f8
--- /dev/null
+++ b/test/rebar_xref_SUITE_data/recursive/apps/rebar_issue1/src/rebar_issue1_sup.erl
@@ -0,0 +1,35 @@
+%%%-------------------------------------------------------------------
+%% @doc rebar_issue1 top level supervisor.
+%% @end
+%%%-------------------------------------------------------------------
+
+-module(rebar_issue1_sup).
+
+-behaviour(supervisor).
+
+%% API
+-export([start_link/0]).
+
+%% Supervisor callbacks
+-export([init/1]).
+
+-define(SERVER, ?MODULE).
+
+%%====================================================================
+%% API functions
+%%====================================================================
+
+start_link() ->
+    supervisor:start_link({local, ?SERVER}, ?MODULE, []).
+
+%%====================================================================
+%% Supervisor callbacks
+%%====================================================================
+
+%% Child :: {Id,StartFunc,Restart,Shutdown,Type,Modules}
+init([]) ->
+    {ok, { {one_for_all, 0, 1}, []} }.
+
+%%====================================================================
+%% Internal functions
+%%====================================================================