Fix null pointer dereferences after dynamic_cast (rewritten)

src/opentimelineio/algo/editAlgorithm.cpp

@@ -181,9 +181,21 @@ overwrite(
             composition->insert_child(insert_index, item);
             if (!isEqual(second_duration.value(), 0.0))
             {
-                auto second_item = dynamic_cast<Item*>(items.front()->clone());
-                trimmed_range    = second_item->trimmed_range();
-                source_range     = TimeRange(
+                auto cloned_item = items.front()->clone(error_status);
+                if (!cloned_item)
+                {
+                    // error_status was already set within clone()
+                    return;
+                }
+                auto second_item = dynamic_cast<Item*>(cloned_item);
+                if (!second_item)
+                {
+                    if (error_status)
+                        *error_status = ErrorStatus::TYPE_MISMATCH;
+                    return;
+                }
+                trimmed_range = second_item->trimmed_range();
+                source_range  = TimeRange(
                     trimmed_range.start_time() + first_duration
                         + range.duration(),
                     second_duration);
@@ -362,7 +374,19 @@ insert(
         // Clone the item for the second partially overwritten item.
         if (!isEqual(second_source_range.duration().value(), 0.0))
         {
-            auto second_item = dynamic_cast<Item*>(item->clone());
+            auto cloned_item = item->clone(error_status);
+            if (!cloned_item)
+            {
+                // error_status was already set within clone()
+                return;
+            }
+            auto second_item = dynamic_cast<Item*>(cloned_item);
+            if (!second_item)
+            {
+                if (error_status)
+                    *error_status = ErrorStatus::TYPE_MISMATCH;
+                return;
+            }
             second_item->set_source_range(second_source_range);
             composition->insert_child(insert_index + 1, second_item);
         }
@@ -530,7 +554,19 @@ slice(
     item->set_source_range(first_source_range);
 
     // Clone the item for the second slice.
-    auto            second_item = dynamic_cast<Item*>(item->clone());
+    auto cloned_item = item->clone(error_status);
+    if (!cloned_item)
+    {
+        // error_status was already set within clone()
+        return;
+    }
+    auto second_item = dynamic_cast<Item*>(cloned_item);
+    if (!second_item)
+    {
+        if (error_status)
+            *error_status = ErrorStatus::TYPE_MISMATCH;
+        return;
+    }
     const TimeRange second_source_range(
         first_source_range.start_time() + first_source_range.duration(),
         range.duration() - first_source_range.duration());
@@ -793,7 +829,19 @@ fill(
         case ReferencePoint::Sequence: {
             RationalTime       start_time     = clip_range.start_time();
             const RationalTime gap_start_time = gap_range.start_time();
-            auto               track_item = dynamic_cast<Item*>(item->clone());
+            auto               cloned_item    = item->clone(error_status);
+            if (!cloned_item)
+            {
+                // error_status was already set within clone()
+                return;
+            }
+            auto track_item = dynamic_cast<Item*>(cloned_item);
+            if (!track_item)
+            {
+                if (error_status)
+                    *error_status = ErrorStatus::TYPE_MISMATCH;
+                return;
+            }
 
             // Check if start time is less than gap's start time (trim it if so)
             if (start_time < gap_start_time)

tests/test_editAlgorithm.cpp

@@ -2131,6 +2131,126 @@ main(int argc, char** argv)
               TimeRange(RationalTime(0.0, 24.0), RationalTime(10.0, 24.0)) });
     });
 
+    tests.add_test("regression: slice fails gracefully", [] {
+        SerializableObject::Retainer<Clip> big_clip = new Clip(
+            "big clip",
+            nullptr,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(24.0, 24.0)));
+        big_clip->metadata()["cycle"] = big_clip;
+
+        SerializableObject::Retainer<Track> track = new Track();
+        track->append_child(big_clip);
+
+        OTIO_NS::ErrorStatus error_status;
+
+        algo::slice(track, RationalTime(12.0, 24.0), false, &error_status);
+
+        assert(is_error(error_status));
+        assert(error_status.outcome == OTIO_NS::ErrorStatus::TYPE_MISMATCH);
+    });
+
+    tests.add_test("regression: overwrite fails gracefully", [] {
+        SerializableObject::Retainer<Clip> big_clip = new Clip(
+            "big clip",
+            nullptr,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(24.0, 24.0)));
+        big_clip->metadata()["cycle"] = big_clip;
+
+        SerializableObject::Retainer<Clip> small_clip = new Clip(
+            "small clip",
+            nullptr,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(5.0, 24.0)));
+        small_clip->metadata()["cycle"] = small_clip;
+
+        SerializableObject::Retainer<Track> track = new Track();
+        track->append_child(big_clip);
+
+        OTIO_NS::ErrorStatus error_status;
+
+        algo::overwrite(
+            small_clip,
+            track,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(12.0, 24.0)),
+            true,
+            nullptr,
+            &error_status);
+
+        assert(is_error(error_status));
+        assert(error_status.outcome == OTIO_NS::ErrorStatus::TYPE_MISMATCH);
+    });
+
+    tests.add_test("regression: insert fails gracefully", [] {
+        SerializableObject::Retainer<Clip> big_clip = new Clip(
+            "big clip",
+            nullptr,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(24.0, 24.0)));
+        big_clip->metadata()["cycle"] = big_clip;
+
+        SerializableObject::Retainer<Clip> small_clip = new Clip(
+            "small clip",
+            nullptr,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(5.0, 24.0)));
+        small_clip->metadata()["cycle"] = small_clip;
+
+        SerializableObject::Retainer<Track> track = new Track();
+        track->append_child(big_clip);
+
+        OTIO_NS::ErrorStatus error_status;
+
+        algo::insert(
+            small_clip,
+            track,
+            RationalTime(12.0, 24.0),
+            true,
+            nullptr,
+            &error_status);
+
+        assert(is_error(error_status));
+        assert(error_status.outcome == OTIO_NS::ErrorStatus::TYPE_MISMATCH);
+    });
+
+    tests.add_test("regression: fill fails gracefully", [] {
+        SerializableObject::Retainer<Clip> big_clip = new Clip(
+            "big clip",
+            nullptr,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(24.0, 24.0)));
+        big_clip->metadata()["cycle"] = big_clip;
+
+        SerializableObject::Retainer<Clip> small_clip = new Clip(
+            "small clip",
+            nullptr,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(5.0, 24.0)));
+        small_clip->metadata()["cycle"] = small_clip;
+
+        SerializableObject::Retainer<Clip> small_clip2 = new Clip(
+            "small clip 2",
+            nullptr,
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(5.0, 24.0)));
+        small_clip2->metadata()["cycle"] = small_clip2;
+
+        SerializableObject::Retainer<Gap> gap = new Gap(
+            TimeRange(RationalTime(0.0, 24.0), RationalTime(20.0, 24.0)),
+            "gap");
+
+        SerializableObject::Retainer<Track> track = new Track();
+        // two small clips with a gap between them
+        track->append_child(small_clip);
+        track->append_child(gap);
+        track->append_child(small_clip2);
+
+        OTIO_NS::ErrorStatus error_status;
+
+        algo::fill(
+            big_clip,
+            track,
+            RationalTime(12.0, 24.0),
+            ReferencePoint::Sequence,
+            &error_status);
+
+        assert(is_error(error_status));
+        assert(error_status.outcome == OTIO_NS::ErrorStatus::TYPE_MISMATCH);
+    });
+
     tests.run(argc, argv);
     return 0;
 }

tests/test_serialization.cpp

@@ -110,6 +110,39 @@ main(int argc, char** argv)
 })CONTENT");
     });
 
+    tests.add_test("clone", [] {
+        auto json     = R"CONTENT({
+  "OTIO_SCHEMA": "SerializableObjectWithMetadata.1",
+  "metadata": {
+    "a": 1,
+    "b": "two",
+    "c": [
+      3,
+      4,
+      5
+    ],
+    "d": {
+      "hello": "nested"
+    }
+  },
+  "name": ""
+})CONTENT";
+        auto original = SerializableObjectWithMetadata::from_json_string(json);
+        auto cloned   = original->clone();
+        assert(cloned != nullptr);
+        OTIO_NS::ErrorStatus err;
+        auto                 cloned_json = cloned->to_json_string(&err, {}, 2);
+        assertFalse(is_error(err));
+        assertEqual(json, cloned_json.c_str());
+    });
+
+    tests.add_test("clone with cycle returns nullptr", [] {
+        auto original                 = new SerializableObjectWithMetadata();
+        original->metadata()["cycle"] = original;
+        auto cloned                   = original->clone();
+        assert(cloned == nullptr);
+    });
+
     tests.run(argc, argv);
     return 0;
 }