Merge branch 'sa/dialyzer-server-loop-fix' into dev

* sa/dialyzer-server-loop-fix:
  Fix server loop detection

OTP-9489

1 files changed, 42 insertions, 0 deletions

diff --git a/lib/dialyzer/test/small_SUITE_data/src/no_return_bug.erl b/lib/dialyzer/test/small_SUITE_data/src/no_return_bug.erl
new file mode 100644
index 0000000000..5c24902590
--- /dev/null
+++ b/lib/dialyzer/test/small_SUITE_data/src/no_return_bug.erl
@@ -0,0 +1,42 @@
+%% Dialyzer couldn't infer that monitor_diskspace would go in an infinite loop
+%% instead of crashing due to the existence of list comprehensions that have a
+%% normal success typing. These were added to the monitor_diskspace's SCC and
+%% dialyzer_typesig didn't try to assign unit() to monitor_diskspace, as it
+%% required all the members of the SCC to return none().
+%%
+%% Testcase was submitted in erlang-questions mailing list by Prashanth Mundkur
+%% (http://erlang.org/pipermail/erlang-questions/2011-May/058063.html)
+
+-module(no_return_bug).
+-export([diskspace/1, monitor_diskspace/2, refresh_tags/1, monitor_launch/0]).
+
+-type diskinfo() :: {non_neg_integer(), non_neg_integer()}.
+
+-spec diskspace(nonempty_string()) -> {'ok', diskinfo()} | {'error', term()}.
+diskspace(Path) ->
+    case Path of
+        "a" -> {ok, {0,0}};
+        _ -> {error, error}
+    end.
+
+-spec monitor_diskspace(nonempty_string(),
+                        [{diskinfo(), nonempty_string()}]) ->
+                               no_return().
+monitor_diskspace(Root, Vols) ->
+    Df = fun(VolName) ->
+                 diskspace(filename:join([Root, VolName]))
+         end,
+    NewVols = [{Space, VolName}
+               || {VolName, {ok, Space}}
+                      <- [{VolName, Df(VolName)}
+                          || {_OldSpace, VolName} <- Vols]],
+    monitor_diskspace(Root, NewVols).
+
+-spec refresh_tags(nonempty_string()) -> no_return().
+refresh_tags(Root) ->
+    {ok, _} = diskspace(Root),
+    refresh_tags(Root).
+
+monitor_launch() ->
+    spawn_link(fun() -> refresh_tags("abc") end),
+    spawn_link(fun() -> monitor_diskspace("root", [{{0,0}, "a"}]) end).