Fix: bt2: autodisc: remove thread error while inserting status in map

If something fails in `bt_bt2_auto_discover_source_components`, we
append an error cause and we go to the error label.  This function
returns a bt_value map containing the return status code and the auto-discovery results, if it was successful.
So we then run into:

	if (result) {
		insert_entry_status = bt_value_map_insert_signed_integer_entry(result, "status", status);
		if (insert_entry_status != BT_VALUE_MAP_INSERT_ENTRY_STATUS_OK) {
			BT_VALUE_PUT_REF_AND_RESET(result);
			PyErr_NoMemory();
		}
	}

However, since there is an error on the current thread, we fail this
precondition:

    06-30 11:27:11.697 3948806 3948806 F LIB/ASSERT-COND bt_lib_assert_cond_failed@assert-cond.c:64 Babeltrace 2 library precondition not satisfied.
    06-30 11:27:11.697 3948806 3948806 F LIB/ASSERT-COND bt_lib_assert_cond_failed@assert-cond.c:66 ------------------------------------------------------------------------
    06-30 11:27:11.697 3948806 3948806 F LIB/ASSERT-COND bt_lib_assert_cond_failed@assert-cond.c:67 Condition ID: `pre:value-map-insert-signed-integer-entry:no-error`.
    06-30 11:27:11.697 3948806 3948806 F LIB/ASSERT-COND bt_lib_assert_cond_failed@assert-cond.c:69 Function: bt_value_map_insert_signed_integer_entry().
    06-30 11:27:11.697 3948806 3948806 F LIB/ASSERT-COND bt_lib_assert_cond_failed@assert-cond.c:70 ------------------------------------------------------------------------
    06-30 11:27:11.697 3948806 3948806 F LIB/ASSERT-COND bt_lib_assert_cond_failed@assert-cond.c:71 Error is:
    06-30 11:27:11.697 3948806 3948806 F LIB/ASSERT-COND bt_lib_assert_cond_failed@assert-cond.c:73 API function called while current thread has an error: function=bt_value_map_insert_signed_integer_entry
    06-30 11:27:11.697 3948806 3948806 F LIB/ASSERT-COND bt_lib_assert_cond_failed@assert-cond.c:76 Aborting...

Change the function to temporarily remove the current thread error,
while inserting the status in the map.  In the unlikely event where the
insertion fail because of a memory error, then we just release the error
and it gets lost.

Cherry-pick note
----------------

Just like the previous commit, the error string expected by the test had
to be updated.

Change-Id: I1b54fb7c8cb0f719fee867e7385dd6a3949cbde4
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/8512
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>
(cherry picked from commit 827e42e017fc5f525aa39a3851bf2e7e50e887aa)
Reviewed-on: https://review.lttng.org/c/babeltrace/+/9512
Tested-by: jenkins <jenkins@lttng.org>

diff --git a/src/bindings/python/bt2/bt2/native_bt_autodisc.i.h b/src/bindings/python/bt2/bt2/native_bt_autodisc.i.h
index 612c9328fd8c6a60a05a528e08a735d2318e0600..f44417b6a8bf919867739c795c2315334e5988ca 100644 (file)
--- a/src/bindings/python/bt2/bt2/native_bt_autodisc.i.h
+++ b/src/bindings/python/bt2/bt2/native_bt_autodisc.i.h
@@ -61,6 +61,7 @@ bt_value *bt_bt2_auto_discover_source_components(const bt_value *inputs,
        bt_value *components_list = NULL;
        bt_value *component_info = NULL;
        bt_value_map_insert_entry_status insert_entry_status;
+       const bt_error *error = NULL;
 
        BT_ASSERT(bt_value_get_type(inputs) == BT_VALUE_TYPE_ARRAY);
        for (i = 0; i < bt_value_array_get_length(inputs); i++) {
@@ -195,11 +196,23 @@ error:
 
 end:
        if (result) {
+               /*
+                * If an error happened, we must clear the error temporarily
+                * while we insert the status in the map.
+                */
+               error = bt_current_thread_take_error();
                insert_entry_status = bt_value_map_insert_signed_integer_entry(result, "status", status);
-               if (insert_entry_status != BT_VALUE_MAP_INSERT_ENTRY_STATUS_OK) {
+               if (insert_entry_status == BT_VALUE_MAP_INSERT_ENTRY_STATUS_OK) {
+                       if (error) {
+                               bt_current_thread_move_error(error);
+                               error = NULL;
+                       }
+               } else {
                        BT_VALUE_PUT_REF_AND_RESET(result);
                        PyErr_NoMemory();
                }
+
+
        }
 
        auto_source_discovery_fini(&auto_disc);
@@ -207,5 +220,9 @@ end:
        bt_value_put_ref(components_list);
        bt_value_put_ref(component_info);
 
+       if (error) {
+               bt_error_release(error);
+       }
+
        return result;
 }

diff --git a/tests/bindings/python/bt2/test_trace_collection_message_iterator.py b/tests/bindings/python/bt2/test_trace_collection_message_iterator.py
index 82c05faaaa256e0bea531d29f376e7f9f01bbccf..ec4a0486a8dd0d22f9e742853007275ac3d58ba3 100644 (file)
--- a/tests/bindings/python/bt2/test_trace_collection_message_iterator.py
+++ b/tests/bindings/python/bt2/test_trace_collection_message_iterator.py
@@ -39,6 +39,10 @@ _AUTO_SOURCE_DISCOVERY_PARAMS_LOG_LEVEL_PATH = os.path.join(
     _BT_TESTS_DATADIR, 'auto-source-discovery', 'params-log-level'
 )
 
+_METADATA_SYNTAX_ERROR_TRACE_PATH = os.path.join(
+    _BT_CTF_TRACES_PATH, "fail", "metadata-syntax-error"
+)
+
 
 class _SomeSource(
     bt2._UserSourceComponent, message_iterator_class=bt2._UserMessageIterator
@@ -722,5 +726,15 @@ class TestAutoDiscoverSourceComponentSpecsParamsObjLogLevel(
         self.assertEqual(msgs[1].stream.name, "TestSourceB: deore")
 
 
+class TestAutoDiscoverFailures(unittest.TestCase):
+    def test_metadata_syntax_error(self):
+        with self.assertRaisesRegex(
+            bt2._Error,
+            'Component class\'s "query" method failed',
+        ):
+            specs = [bt2.AutoSourceComponentSpec(_METADATA_SYNTAX_ERROR_TRACE_PATH)]
+            bt2.TraceCollectionMessageIterator(specs)
+
+
 if __name__ == '__main__':
     unittest.main()