Added chicken and egg recursion detection

src/core/sheerka/Sheerka.py

@@ -249,11 +249,12 @@ class Sheerka(Concept):
             if not self.skip_builtins_in_db:
                 self.sdp.save_result(self, execution_context)
 
-            # hack to save valid concept definition
-            if not self.during_restore:
-                if len(ret) == 1 and ret[0].status and self.isinstance(ret[0].value, BuiltinConcepts.NEW_CONCEPT):
-                    with open(CONCEPTS_FILE, "a") as f:
-                        f.write(text + "\n")
+        # hack to save valid concept definition
+        # if not self.during_restore:
+        #     if len(ret) == 1 and ret[0].status and self.isinstance(ret[0].value, BuiltinConcepts.NEW_CONCEPT):
+        #         with open(CONCEPTS_FILE, "a") as f:
+        #             f.write(text + "\n")
+
         return ret
 
     def execute(self, execution_context, return_values, execution_steps, logger=None):
@@ -364,19 +365,26 @@ class Sheerka(Concept):
             concept_key = str(concept_key)
 
         # first search in cache
-        result = self.cache_by_key[concept_key] if concept_key in self.cache_by_key else \
-            self.sdp.get_safe(self.CONCEPTS_ENTRY, concept_key)
+        if concept_key in self.cache_by_key:
+            result = self.cache_by_key[concept_key]
+        else:
+            result = self.sdp.get_safe(self.CONCEPTS_ENTRY, concept_key)
+            if result is None:
+                metadata = [("key", concept_key), ("id", concept_id)] if concept_id else ("key", concept_key)
+                result = self._get_unknown(metadata)
 
-        if result and (concept_id is None or not isinstance(result, list)):
+            self.cache_by_key[concept_key] = result
+            for r in (result if isinstance(result, list) else [result]):
+                if r.id:
+                    self.cache_by_id[r.id] = r
+
+        if not (isinstance(result, list) and concept_id):
             return result
 
-        if isinstance(result, list):
-            if concept_id:
-                for c in result:
-                    if c.id == concept_id:
-                        return c
-            else:
-                return result
+        # result is a list, but we have the concept_id to discriminate
+        for c in result:
+            if c.id == concept_id:
+                return c
 
         metadata = [("key", concept_key), ("id", concept_id)] if concept_id else ("key", concept_key)
         return self._get_unknown(metadata)
@@ -386,10 +394,15 @@ class Sheerka(Concept):
             return ErrorConcept("Concept id is undefined.")
 
         # first search in cache
-        result = self.cache_by_id[concept_id] if concept_id in self.cache_by_id else \
-            self.sdp.get_safe(self.CONCEPTS_BY_ID_ENTRY, concept_id)
+        if concept_id in self.cache_by_id:
+            result = self.cache_by_id[concept_id]
+        else:
+            result = self.sdp.get_safe(self.CONCEPTS_BY_ID_ENTRY, concept_id)
+            if result is None:
+                result = self._get_unknown(('id', concept_id))
+            self.cache_by_id[concept_id] = result
 
-        return result or self._get_unknown(('id', concept_id))
+        return result
 
     def get_concepts_definitions(self, context):
         if self.concepts_definitions_cache: