[nullsafe][annotation graph] Annotation graph: introduce ProvisionalAnnotation

Summary:
This is the basic building blocks for the future annotation graph. This
diff introduces the first abstraction to be iterated on.

Reviewed By: artempyanykh

Differential Revision: D24621414

fbshipit-source-id: 19acdf216

infer/man/man1/infer-full.txt

@@ -1633,6 +1633,11 @@ INTERNAL OPTIONS
            typechecker, use `--eradicate` for now. (Conversely:
            --no-nullsafe)
 
+       --nullsafe-annotation-graph
+           Activates: Nullsafe: an experimental mode for calculating the
+           dependency graph between potential annotations to add in the
+           source code. (Conversely: --no-nullsafe-annotation-graph)
+
        --nullsafe-disable-field-not-initialized-in-nonstrict-classes
            Activates: Nullsafe: In this mode field not initialized issues
            won't be reported unless the class is marked as @NullsafeStrict.

infer/src/base/Config.ml

@@ -1617,6 +1617,12 @@ and nullable_annotation =
   CLOpt.mk_string_opt ~long:"nullable-annotation-name" "Specify custom nullable annotation name"
 
 
+and nullsafe_annotation_graph =
+  CLOpt.mk_bool ~long:"nullsafe-annotation-graph"
+    "Nullsafe: an experimental mode for calculating the dependency graph between potential \
+     annotations to add in the source code."
+
+
 and nullsafe_disable_field_not_initialized_in_nonstrict_classes =
   CLOpt.mk_bool ~long:"nullsafe-disable-field-not-initialized-in-nonstrict-classes" ~default:false
     "Nullsafe: In this mode field not initialized issues won't be reported unless the class is \
@@ -2942,6 +2948,8 @@ and nelseg = !nelseg
 
 and nullable_annotation = !nullable_annotation
 
+and nullsafe_annotation_graph = !nullsafe_annotation_graph
+
 and nullsafe_disable_field_not_initialized_in_nonstrict_classes =
   !nullsafe_disable_field_not_initialized_in_nonstrict_classes
 

infer/src/base/Config.mli

@@ -393,6 +393,8 @@ val no_translate_libs : bool
 
 val nullable_annotation : string option
 
+val nullsafe_annotation_graph : bool
+
 val nullsafe_disable_field_not_initialized_in_nonstrict_classes : bool
 
 val nullsafe_optimistic_third_party_params_in_non_strict : bool

infer/src/nullsafe/AnnotatedNullability.ml

@@ -17,6 +17,7 @@ module F = Format
 (** See {!Nullability.t} for explanation *)
 type t =
   | Nullable of nullable_origin
+  | ProvisionallyNullable of ProvisionalAnnotation.t
   | ThirdPartyNonnull
   | UncheckedNonnull of unchecked_nonnull_origin
   | LocallyTrustedNonnull
@@ -45,6 +46,8 @@ and strict_nonnull_origin =
 let get_nullability = function
   | Nullable _ ->
       Nullability.Nullable
+  | ProvisionallyNullable _ ->
+      Nullability.Nullable
   | ThirdPartyNonnull ->
       Nullability.ThirdPartyNonnull
   | UncheckedNonnull _ ->
@@ -90,6 +93,8 @@ let pp fmt t =
   match t with
   | Nullable origin ->
       F.fprintf fmt "Nullable[%s]" (string_of_nullable_origin origin)
+  | ProvisionallyNullable _ ->
+      F.fprintf fmt "ProvisionallyNullable"
   | ThirdPartyNonnull ->
       F.fprintf fmt "ThirdPartyNonnull"
   | UncheckedNonnull origin ->

infer/src/nullsafe/AnnotatedNullability.mli

@@ -19,6 +19,7 @@ open! IStd
 (** See {!Nullability.t} for explanation *)
 type t =
   | Nullable of nullable_origin
+  | ProvisionallyNullable of ProvisionalAnnotation.t  (** Exist only for specical run modes *)
   | ThirdPartyNonnull
   | UncheckedNonnull of unchecked_nonnull_origin
   | LocallyTrustedNonnull

infer/src/nullsafe/AnnotatedSignature.ml

@@ -41,8 +41,8 @@ let get_non_virtual_params {params} =
 
 
 (* get nullability of method's return type given its annotations and information about its params *)
-let nullability_for_return ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party ret_type
-    ret_annotations ~has_propagates_nullable_in_param =
+let nullability_for_return ~proc_name ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party
+    ~is_provisional_annotation_mode ret_type ret_annotations ~has_propagates_nullable_in_param =
   let nullability =
     AnnotatedNullability.of_type_and_annotation ~is_callee_in_trust_list ~nullsafe_mode
       ~is_third_party ret_type ret_annotations
@@ -54,18 +54,37 @@ let nullability_for_return ~is_callee_in_trust_list ~nullsafe_mode ~is_third_par
   | _ when has_propagates_nullable_in_param ->
       (* if any params is propagates nullable, the return type can be only nullable *)
       AnnotatedNullability.Nullable AnnotatedNullability.HasPropagatesNullableInParam
+  | _ when is_provisional_annotation_mode ->
+      (* Not explicitly annotated with [@Nullable] - make it provisionally nullable  *)
+      AnnotatedNullability.ProvisionallyNullable (ProvisionalAnnotation.Method proc_name)
+  | _ ->
+      nullability
+
+
+let nullability_for_param ~proc_name ~param_num ~is_callee_in_trust_list ~nullsafe_mode
+    ~is_third_party ~is_provisional_annotation_mode param_type param_annotations =
+  let nullability =
+    AnnotatedNullability.of_type_and_annotation ~is_callee_in_trust_list ~nullsafe_mode
+      ~is_third_party param_type param_annotations
+  in
+  match nullability with
+  | AnnotatedNullability.Nullable _ ->
+      nullability
+  | _ when is_provisional_annotation_mode ->
+      AnnotatedNullability.ProvisionallyNullable
+        (ProvisionalAnnotation.Param {method_info= proc_name; num= param_num})
   | _ ->
       nullability
 
 
 (* Given annotations for method signature, extract nullability information
    for return type and params *)
-let extract_nullability ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party ret_type
-    ret_annotations param_annotated_types =
+let extract_nullability ~proc_name ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party
+    ~is_provisional_annotation_mode ret_type ret_annotations param_annotated_types =
   let params_nullability =
-    List.map param_annotated_types ~f:(fun (typ, annotations) ->
-        AnnotatedNullability.of_type_and_annotation ~is_callee_in_trust_list ~nullsafe_mode
-          ~is_third_party typ annotations )
+    List.mapi param_annotated_types ~f:(fun param_num (param_type, param_annotations) ->
+        nullability_for_param ~proc_name ~param_num ~is_callee_in_trust_list ~nullsafe_mode
+          ~is_third_party ~is_provisional_annotation_mode param_type param_annotations )
   in
   let has_propagates_nullable_in_param =
     List.exists params_nullability ~f:(function
@@ -75,13 +94,13 @@ let extract_nullability ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party
           false )
   in
   let return_nullability =
-    nullability_for_return ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party ret_type
-      ret_annotations ~has_propagates_nullable_in_param
+    nullability_for_return ~proc_name ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party
+      ret_type ~is_provisional_annotation_mode ret_annotations ~has_propagates_nullable_in_param
   in
   (return_nullability, params_nullability)
 
 
-let get ~is_callee_in_trust_list ~nullsafe_mode
+let get_impl ~is_callee_in_trust_list ~nullsafe_mode ~is_provisional_annotation_mode
     ( {ProcAttributes.proc_name; ret_type; method_annotation= {return= ret_annotation}} as
     proc_attributes ) : t =
   let proc_name =
@@ -98,8 +117,8 @@ let get ~is_callee_in_trust_list ~nullsafe_mode
     List.map params_with_annotations ~f:(fun ((_, typ), annotations) -> (typ, annotations))
   in
   let return_nullability, params_nullability =
-    extract_nullability ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party ret_type
-      ret_annotation param_annotated_types
+    extract_nullability ~proc_name ~is_callee_in_trust_list ~nullsafe_mode ~is_third_party
+      ~is_provisional_annotation_mode ret_type ret_annotation param_annotated_types
   in
   let ret =
     { ret_annotation_deprecated= ret_annotation
@@ -116,6 +135,8 @@ let get ~is_callee_in_trust_list ~nullsafe_mode
   {nullsafe_mode; kind; ret; params}
 
 
+let get = get_impl ~is_provisional_annotation_mode:false
+
 let get_for_class_under_analysis tenv proc_attributes =
   (* Signature makes special meaning when the method is inside the class we are currently analysing.
      Various non-nullable levels (as dictated by nullsafe mode of the class)
@@ -125,7 +146,8 @@ let get_for_class_under_analysis tenv proc_attributes =
      We achieve it via passing Strict mode to the signature extractor.
   *)
   let result =
-    get ~is_callee_in_trust_list:false ~nullsafe_mode:NullsafeMode.Strict proc_attributes
+    get_impl ~is_callee_in_trust_list:false ~nullsafe_mode:NullsafeMode.Strict proc_attributes
+      ~is_provisional_annotation_mode:Config.nullsafe_annotation_graph
   in
   (* Don't forget about the original mode *)
   let nullsafe_mode = NullsafeMode.of_procname tenv proc_attributes.ProcAttributes.proc_name in

infer/src/nullsafe/ProvisionalAnnotation.ml

@@ -0,0 +1,13 @@
+(*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *)
+open! IStd
+
+type t =
+  | Field of {field_name: string}
+  | Method of Procname.Java.t
+  | Param of {method_info: Procname.Java.t; num: int}
+[@@deriving compare]

infer/src/nullsafe/ProvisionalAnnotation.mli

@@ -0,0 +1,18 @@
+(*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *)
+open! IStd
+
+(** Provisional annotation is an imaginary [@Nullable] annotation that is added to a class element.
+    * (It implies the corresponding element is NOT annotated as [@Nullable] in the source code.) *
+    The purpose of provisional annotation is to compute Nullability graph: what would happen if such
+    and such * element was annotated as [@Nullable]. *)
+
+type t =
+  | Field of {field_name: string}
+  | Method of Procname.Java.t
+  | Param of {method_info: Procname.Java.t; num: int}
+[@@deriving compare]

infer/src/nullsafe/typeOrigin.ml

@@ -64,6 +64,8 @@ let get_nullability = function
     | AnnotatedNullability.Nullable _ ->
         (* Annotated as Nullable explicitly or implicitly *)
         Nullability.Nullable
+    | AnnotatedNullability.ProvisionallyNullable _ ->
+        Nullability.Nullable
     | AnnotatedNullability.UncheckedNonnull _
     | AnnotatedNullability.ThirdPartyNonnull
     | AnnotatedNullability.LocallyTrustedNonnull
@@ -134,6 +136,10 @@ let get_method_ret_description pname call_loc
     match nullability with
     | AnnotatedNullability.Nullable _ ->
         "nullable"
+    | AnnotatedNullability.ProvisionallyNullable _ ->
+        (* There should not be scenario where this is explained to the end user. *)
+        Logging.die InternalError
+          "get_method_ret_description: Unexpected nullability: ProvisionallyNullable"
     | AnnotatedNullability.ThirdPartyNonnull
     | AnnotatedNullability.UncheckedNonnull _
     | AnnotatedNullability.LocallyTrustedNonnull