raise PublishXmlValidationError in validate layers visibility

openpype/hosts/tvpaint/plugins/publish/help/validate_layers_visibility.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<root>
+<error id="main">
+<title>Layers visiblity</title>
+<description>## All layers are not visible
+
+All layers for subset "{instance_name}" are hidden.
+
+### Layer names for **{instance_name}**
+
+{layer_names}
+
+*Check layer names for all subsets in list on left side.*
+
+### How to repair?
+
+Make sure that at least one layer in the scene is visible or disable the subset before hitting publish button after refresh.
+</description>
+</error>
+</root>

openpype/hosts/tvpaint/plugins/publish/validate_layers_visibility.py

@@ -1,6 +1,8 @@
 import pyblish.api
+from openpype.pipeline import PublishXmlValidationError
 
 
+# TODO @iLLiCiTiT add repair action to disable instances?
 class ValidateLayersVisiblity(pyblish.api.InstancePlugin):
     """Validate existence of renderPass layers."""
 
@@ -9,8 +11,26 @@ class ValidateLayersVisiblity(pyblish.api.InstancePlugin):
     families = ["review", "renderPass", "renderLayer"]
 
     def process(self, instance):
+        layer_names = set()
         for layer in instance.data["layers"]:
+            layer_names.add(layer["name"])
             if layer["visible"]:
                 return
 
-        raise AssertionError("All layers of instance are not visible.")
+        instance_label = (
+            instance.data.get("label") or instance.data["name"]
+        )
+
+        raise PublishXmlValidationError(
+            self,
+            "All layers of instance \"{}\" are not visible.".format(
+                instance_label
+            ),
+            formatting_data={
+                "instance_name": instance_label,
+                "layer_names": "<br/>".join([
+                    "- {}".format(layer_name)
+                    for layer_name in layer_names
+                ])
+            }
+        )