feat: default value for formulas (#119)

* init

* init

* imporve comment

* sgdijsdlgj

Author: Kyle Mumma

proto/sentry_protos/snuba/v1/endpoint_time_series.proto

@@ -65,6 +65,12 @@ message Expression {
     Op op = 1;
     Expression left = 2;
     Expression right = 3;
+    // optional, if the formula evalutates to null this value is returned
+    // formula can evaluate to null if an attribute is missing for example
+    oneof default_value {
+      double default_value_double = 4;
+      int64 default_value_int64 = 5;
+    }
   }
 }
 

proto/sentry_protos/snuba/v1/endpoint_trace_item_table.proto

@@ -97,6 +97,12 @@ message Column {
     Op op = 1;
     Column left = 2;
     Column right = 3;
+    // optional, if the formula evalutates to null this value is returned
+    // formula can evaluate to null if an attribute is missing for example
+    oneof default_value {
+      double default_value_double = 4;
+      int64 default_value_int64 = 5;
+    }
   }
 }
 

py/tests/test_snuba_v1.py

@@ -130,6 +130,7 @@ def test_example_time_series():
                         ),
                         label="p90",
                     ),
+                    default_value_double=1.0,
                 ),
                 label="p50 / p90"
             ),