Support Decimal 2.x (#519)

lib/postgrex/extensions/numeric.ex

@@ -28,7 +28,8 @@ defmodule Postgrex.Extensions.Numeric do
 
   ## Helpers
 
-  def encode_numeric(%Decimal{coef: coef}) when coef in [:qNaN, :sNaN] do
+  # TODO: remove qNaN and sNaN when we depend on Decimal 2.0
+  def encode_numeric(%Decimal{coef: coef}) when coef in [:NaN, :qNaN, :sNaN] do
     <<0::int16, 0::int16, 0xC000::uint16, 0::int16>>
   end
 
@@ -90,8 +91,10 @@ defmodule Postgrex.Extensions.Numeric do
     decode_numeric(ndigits, weight, sign, scale, tail)
   end
 
+  @nan Decimal.new("NaN")
+
   defp decode_numeric(0, _weight, 0xC000, _scale, "") do
-    Decimal.new(1, :qNaN, 0)
+    @nan
   end
 
   defp decode_numeric(_num_digits, weight, sign, scale, bin) do

mix.exs

@@ -31,7 +31,7 @@ defmodule Postgrex.Mixfile do
     [
       {:ex_doc, "~> 0.20", only: :docs},
       {:jason, "~> 1.0", optional: true},
-      {:decimal, "~> 1.5"},
+      {:decimal, "~> 1.5 or ~> 2.0"},
       {:db_connection, "~> 2.1"},
       {:connection, "~> 1.0"}
     ]

mix.lock

@@ -1,7 +1,7 @@
 %{
   "connection": {:hex, :connection, "1.0.4", "a1cae72211f0eef17705aaededacac3eb30e6625b04a6117c1b2db6ace7d5976", [:mix], [], "hexpm", "4a0850c9be22a43af9920a71ab17c051f5f7d45c209e40269a1938832510e4d9"},
   "db_connection": {:hex, :db_connection, "2.1.0", "122e2f62c4906bf2e49554f1e64db5030c19229aa40935f33088e7d543aa79d0", [:mix], [{:connection, "~> 1.0.2", [hex: :connection, repo: "hexpm", optional: false]}], "hexpm", "f398f3144db606de82ed42c2ddc69767f0607abdb796e8220de5f0fcf80f5ba4"},
-  "decimal": {:hex, :decimal, "1.6.0", "bfd84d90ff966e1f5d4370bdd3943432d8f65f07d3bab48001aebd7030590dcc", [:mix], [], "hexpm", "bbd124e240e3ff40f407d50fced3736049e72a73d547f69201484d3a624ab569"},
+  "decimal": {:hex, :decimal, "1.9.0", "83e8daf59631d632b171faabafb4a9f4242c514b0a06ba3df493951c08f64d07", [:mix], [], "hexpm", "b1f2343568eed6928f3e751cf2dffde95bfaa19dd95d09e8a9ea92ccfd6f7d85"},
   "earmark": {:hex, :earmark, "1.4.4", "4821b8d05cda507189d51f2caeef370cf1e18ca5d7dfb7d31e9cafe6688106a4", [:mix], [], "hexpm", "1f93aba7340574847c0f609da787f0d79efcab51b044bb6e242cae5aca9d264d"},
   "ex_doc": {:hex, :ex_doc, "0.22.1", "9bb6d51508778193a4ea90fa16eac47f8b67934f33f8271d5e1edec2dc0eee4c", [:mix], [{:earmark, "~> 1.4.0", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm", "d957de1b75cb9f78d3ee17820733dc4460114d8b1e11f7ee4fd6546e69b1db60"},
   "jason": {:hex, :jason, "1.1.1", "d3ccb840dfb06f2f90a6d335b536dd074db748b3e7f5b11ab61d239506585eb2", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "639645cfac325e34938167b272bae0791fea3a34cf32c29525abf1d323ed4c18"},