Merge pull request #1608 from fsprojects/repo-assist/fix-json-decimal-float-1230-a945dd1e3b1536f6

[Repo Assist] Fix JsonConversions.AsDecimal to handle JsonValue.Float

Author: dsyme

src/FSharp.Data.Json.Core/JsonConversions.fs

@@ -47,6 +47,11 @@ type JsonConversions =
     static member AsDecimal cultureInfo =
         function
         | JsonValue.Number n -> Some n
+        | JsonValue.Float f when not (Double.IsInfinity f) && not (Double.IsNaN f) ->
+            try
+                Some(decimal f)
+            with :? OverflowException ->
+                None
         | JsonValue.String s -> TextConversions.AsDecimal cultureInfo s
         | _ -> None
 

tests/FSharp.Data.Tests/JsonProvider.fs

@@ -816,6 +816,18 @@ let ``ParseList return result list`` () =
   let prov = NumericFields.ParseList(""" [{"a":123}, {"a":987}] """)
   prov |> Array.map (fun v -> v.A) |> Array.sort |> should equal [|123M; 987M|]
 
+// Regression test for https://github.com/fsprojects/FSharp.Data/issues/1230
+// When a JSON array sample mixes decimal and exponential-notation numbers, the inferred
+// type is decimal (because the exponential value is stored as JsonValue.Float and inferred
+// as integer, which is then unified with decimal).  At runtime, any exponential-notation
+// number in the actual JSON must also be convertible to decimal.
+type ExponentialDecimalProvider = JsonProvider<"""{"mydata": [1, 2.34567E5, 3.14]}""">
+
+[<Test>]
+let ``Decimal inferred from mixed-notation array can parse exponential notation at runtime`` () =
+    let result = ExponentialDecimalProvider.Parse("""{"mydata": [2, 3.45678E5, 9.01]}""")
+    result.Mydata |> should equal [| 2M; 345678M; 9.01M |]
+
 
 type ServiceResponse = JsonProvider<"""[
 { "code": 0, "value": {"generic payload": "yes"}, "message": null},