[nullsafe][annotation graph] Don't fail while dealing with synthetic fields

Summary:
Sometimes there are annotations that don't correspond to the user facing
code.
Previously we would fail, now process them gracefully.

Reviewed By: artempyanykh

Differential Revision: D24890895

fbshipit-source-id: e64a866ec

infer/src/nullsafe/AnnotationGraph.ml

@@ -99,10 +99,6 @@ let get_fix_annotation = function
 
 let update_by_violation nodes provisional_violation =
   let fix_annotation = get_fix_annotation provisional_violation in
-  Option.iter fix_annotation ~f:(fun annotation ->
-      if not (AnnotationMap.mem annotation nodes) then
-        Logging.die InternalError "Did not find a node for %a in the graph" ProvisionalAnnotation.pp
-          annotation ) ;
   let offending_annotations = get_offending_annotations provisional_violation in
   List.iter offending_annotations ~f:(fun annotation ->
       match AnnotationMap.find_opt annotation nodes with
@@ -112,17 +108,31 @@ let update_by_violation nodes provisional_violation =
             (* If that provisional annotation becomes real [@Nullable], that would raise an issue fixable by the other annotation.
                Add the new edge in the graph.
             *)
+            if AnnotationMap.mem fix_annotation nodes then
               annotation_point.dependent_points <-
                 List.dedup_and_sort
                   (fix_annotation :: annotation_point.dependent_points)
                   ~compare:ProvisionalAnnotation.compare
+            else (
+              (* This is an edge case sitation. There is a corresponding ProvisionalAnnotation for this Java class, but
+                 it is not in the list of the known provisional annotations for the class.
+                 This can happen for e.g. syntethic fields / autogenerated code or other not yet supporte cases.
+                 Conservatively record this situation as an unfixable violation.
+              *)
+              Logging.debug Analysis Medium
+                "Did not find a node for %a in the graph: recording a violation instead"
+                ProvisionalAnnotation.pp fix_annotation ;
+              annotation_point.num_violations <- annotation_point.num_violations + 1 )
         | None ->
             (* If that provisional annotation becomes real [@Nullable], that would lead to a violation
              * (not related to other provisional annotations).
              *)
             annotation_point.num_violations <- annotation_point.num_violations + 1 )
       | None ->
-          Logging.die InternalError "Did not find a node for %a in the graph"
+          (* This is not a real annotation point. This can happen for synthetic fields etc.
+           *)
+          Logging.debug Analysis Medium
+            "Did not find a node for %a in the graph: not processing this annotation"
             ProvisionalAnnotation.pp annotation )