Added support for adapters in guard handler

CHANGES.rst

@@ -6,6 +6,7 @@ Changelog
 
 **Added**
 
+- #1455 Added support for adapters in guard handler
 - #1436 Setting in setup for auto-reception of samples upon creation
 - #1433 Added Submitter column in Sample's analyses listing
 - #1441 Added Auto ID Behavior for Dexterity Contents

bika/lims/interfaces/__init__.py

@@ -954,3 +954,12 @@ class IInternalUse(Interface):
 class IDetachedPartition(Interface):
     """Marker interface for samples that have been detached from its primary
     """
+
+
+class IGuardAdapter(Interface):
+    """Marker interface for guard adapters
+    """
+
+    def guard(self, transition):
+        """Return False if you want to block the transition
+        """

bika/lims/workflow/__init__.py

@@ -28,7 +28,7 @@
 from bika.lims import logger
 from bika.lims.browser import ulocalized_time
 from bika.lims.decorators import synchronized
-from bika.lims.interfaces import IActionHandlerPool
+from bika.lims.interfaces import IActionHandlerPool, IGuardAdapter
 from bika.lims.interfaces import IJSONReadExtender
 from bika.lims.jsonapi import get_include_fields
 from bika.lims.utils import changeWorkflowState  # noqa
@@ -37,6 +37,7 @@
 from Products.Archetypes.config import UID_CATALOG
 from Products.CMFCore.utils import getToolByName
 from Products.CMFCore.WorkflowCore import WorkflowException
+from zope.component import getAdapters
 from zope.interface import implements
 from ZPublisher.HTTPRequest import HTTPRequest
 
@@ -386,6 +387,13 @@ def guard_handler(instance, transition_id):
     """
     if not instance:
         return True
+
+    # If adapters are found, core's guard will only be evaluated if, and only
+    # if, ALL "pre-guards" return True
+    for name, ad in getAdapters((instance,), IGuardAdapter):
+        if ad.guard(transition_id) is False:
+            return False
+
     clazz_name = instance.portal_type
     # Inspect if bika.lims.workflow.<clazzname>.<guards> module exists
     wf_module = _load_wf_module('{0}.guards'.format(clazz_name.lower()))