Treat parse errors in pysa files as model verification errors (closes #431)

Summary: We currently throw an exception on syntax errors in pysa files. This means that `pyre query validate_taint_models()` returns an error with a different format than a regular model verification error. This is problematic for the VSCode plugin we are trying to implement, which relies on `pyre query` returning errors in a given format.

Reviewed By: dkgi

Differential Revision: D28950011

fbshipit-source-id: 0792108da6f301abddd4b88320a88bcfc4f5750b

Author: arthaud

source/interprocedural_analyses/taint/modelParser.ml

@@ -2371,17 +2371,21 @@ let create_model_from_attribute
 
 
 let create ~resolution ~path ~configuration ~rule_filter source =
+  let open Core.Result in
   let sources_to_keep, sinks_to_keep =
     compute_sources_and_sinks_to_keep ~configuration ~rule_filter
   in
   let signatures_and_queries, errors =
     String.split ~on:'\n' source
-    |> Parser.parse_exn
-    |> Source.create
-    |> Source.statements
-    |> List.map ~f:(parse_statement ~resolution ~path ~configuration)
-    |> List.partition_result
-    |> fun (results, errors) -> List.concat results, errors
+    |> Parser.parse
+    >>| Source.create
+    >>| Source.statements
+    >>| List.map ~f:(parse_statement ~resolution ~path ~configuration)
+    >>| List.partition_result
+    |> function
+    | Ok (results, errors) -> List.concat results, errors
+    | Error { Parser.Error.location; _ } ->
+        [], [model_verification_error ~path ~location ParseError]
   in
   let create_model_or_query = function
     | ParsedSignature parsed_signature ->

source/interprocedural_analyses/taint/modelVerificationError.ml

@@ -19,6 +19,7 @@ module T = struct
   [@@deriving sexp, compare, eq, show]
 
   type kind =
+    | ParseError
     | InvalidDefaultValue of {
         callable_name: string;
         name: string;
@@ -91,6 +92,7 @@ include T
 
 let description error =
   match error with
+  | ParseError -> "Syntax error."
   | InvalidDefaultValue { callable_name; name; expression } ->
       Format.sprintf
         "Default values of `%s`'s parameters must be `...`. Did you mean to write `%s: %s`?"
@@ -177,7 +179,7 @@ let description error =
       Format.sprintf
         "Invalid identifier: `%s`. Expected a fully-qualified name."
         (Expression.show expression)
-  | UnexpectedStatement _ -> "Unexpected statement"
+  | UnexpectedStatement _ -> "Unexpected statement."
   | ClassBodyNotEllipsis class_name ->
       Format.sprintf "Class model for `%s` must have a body of `...`." class_name
   | DefineBodyNotEllipsis model_name ->
@@ -241,6 +243,7 @@ let code { kind; _ } =
   | ClassBodyNotEllipsis _ -> 22
   | DefineBodyNotEllipsis _ -> 23
   | InvalidNameClause _ -> 24
+  | ParseError -> 25
 
 
 let display { kind = error; path; location } =

source/interprocedural_analyses/taint/modelVerificationError.mli

@@ -17,6 +17,7 @@ module T : sig
   [@@deriving sexp, compare, eq]
 
   type kind =
+    | ParseError
     | InvalidDefaultValue of {
         callable_name: string;
         name: string;

source/interprocedural_analyses/taint/test/modelTest.ml

@@ -1198,7 +1198,8 @@ let test_invalid_models context =
   let assert_valid_model ?source ?sources ~model_source () =
     assert_invalid_model ?source ?sources ~model_source ~expect:"no failure" ()
   in
-  assert_invalid_model ~model_source:"import foo" ~expect:"Unexpected statement" ();
+  assert_invalid_model ~model_source:"1 + import" ~expect:"Syntax error." ();
+  assert_invalid_model ~model_source:"import foo" ~expect:"Unexpected statement." ();
   assert_invalid_model
     ~model_source:"def test.sink(parameter: TaintSink[X, Unsupported]) -> TaintSource[A]: ..."
     ~expect: