lib: clear error in clock_snapshots_are_monotonic_one

When bt_clock_snapshot_get_ns_from_origin is called in
clock_snapshots_are_monotonic_one, it can return OVERFLOW_ERROR, in
which case it also sets the current thread error.
clock_snapshots_are_monotonic_one doesn't report an error status to its
caller (it's not its goal), so it should not leave the error there.

This is exercised when running Python test
ClockSnapshotTestCase.test_clock_class.

Change-Id: I0f15c2607c299fabc3a89e6a292d97d8d5815fc4
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/2360
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>

diff --git a/src/lib/graph/iterator.c b/src/lib/graph/iterator.c
index 121e4bd9a8ed4ca70eb4d6971b83d0d9cd97ea27..40acd76dec671af0546b41db2f5517fce99a0bb1 100644 (file)
--- a/src/lib/graph/iterator.c
+++ b/src/lib/graph/iterator.c
@@ -643,8 +643,15 @@ bool clock_snapshots_are_monotonic_one(
                goto end;
        }
 
-       clock_snapshot_status = bt_clock_snapshot_get_ns_from_origin(clock_snapshot, &ns_from_origin);
+       clock_snapshot_status = bt_clock_snapshot_get_ns_from_origin(
+               clock_snapshot, &ns_from_origin);
        if (clock_snapshot_status != BT_FUNC_STATUS_OK) {
+               /*
+                * bt_clock_snapshot_get_ns_from_origin can return
+                * OVERFLOW_ERROR.  We don't really want to report an error to
+                * our caller, so just clear it.
+                */
+               bt_current_thread_clear_error();
                goto end;
        }