Fix some exceptions reporting (#36)

Some erlang errors (bad arithmetic, no case clause matching, undefined
functions, etc.) along with throws and exists were not being recorded
properly.

This commit reports them well and handles the case in which the source
file and line are unknown.

Author: odarriba

lib/error_tracker.ex

@@ -94,26 +94,11 @@ defmodule ErrorTracker do
   * An exception struct: the module of the exception is stored along with
   the exception message.
 
-  * A `{kind, exception}` tuple in which the `exception` is a struct: it
-  behaves the same as when passing just the exception struct.
-
-  * A `{kind, reason}` tuple: it stores the kind and the message itself cast
-  to strings, which is useful for some errors like EXIT signals or custom error
-  messages.
+  * A `{kind, exception}` tuple in which case the information is converted to
+  an Elixir exception (if possible) and stored.
   """
   def report(exception, stacktrace, given_context \\ %{}) do
-    {kind, reason} =
-      case exception do
-        %struct{} = ex when is_exception(ex) ->
-          {to_string(struct), Exception.message(ex)}
-
-        {_kind, %struct{} = ex} when is_exception(ex) ->
-          {to_string(struct), Exception.message(ex)}
-
-        {kind, ex} ->
-          {to_string(kind), to_string(ex)}
-      end
-
+    {kind, reason} = normalize_exception(exception, stacktrace)
     {:ok, stacktrace} = ErrorTracker.Stacktrace.new(stacktrace)
     {:ok, error} = Error.new(kind, reason, stacktrace)
 
@@ -181,4 +166,18 @@ defmodule ErrorTracker do
   def get_context do
     Process.get(:error_tracker_context, %{})
   end
+
+  defp normalize_exception(%struct{} = ex, _stacktrace) when is_exception(ex) do
+    {to_string(struct), Exception.message(ex)}
+  end
+
+  defp normalize_exception({kind, ex}, stacktrace) do
+    case Exception.normalize(kind, ex, stacktrace) do
+      %struct{} = ex ->
+        {to_string(struct), Exception.message(ex)}
+
+      other ->
+        {to_string(kind), to_string(other)}
+    end
+  end
 end

lib/error_tracker/schemas/error.ex

@@ -29,10 +29,11 @@ defmodule ErrorTracker.Error do
   @doc false
   def new(kind, reason, stacktrace = %ErrorTracker.Stacktrace{}) do
     source = ErrorTracker.Stacktrace.source(stacktrace)
+    source_line = if source.file, do: "#{source.file}:#{source.line}", else: "nofile"
 
     params = [
       kind: to_string(kind),
-      source_line: "#{source.file}:#{source.line}",
+      source_line: source_line,
       source_function: "#{source.module}.#{source.function}/#{source.arity}"
     ]
 

lib/error_tracker/schemas/stacktrace.ex

@@ -27,7 +27,7 @@ defmodule ErrorTracker.Stacktrace do
           application: to_string(application),
           module: module |> to_string() |> String.replace_prefix("Elixir.", ""),
           function: to_string(function),
-          arity: arity,
+          arity: normalize_arity(arity),
           file: to_string(opts[:file]),
           line: opts[:line]
         }
@@ -39,6 +39,9 @@ defmodule ErrorTracker.Stacktrace do
     |> Ecto.Changeset.apply_action(:new)
   end
 
+  defp normalize_arity(a) when is_integer(a), do: a
+  defp normalize_arity(a) when is_list(a), do: length(a)
+
   defp line_changeset(line = %__MODULE__.Line{}, params) do
     Ecto.Changeset.cast(line, params, ~w[application module function arity file line]a)
   end

lib/error_tracker/web/live/show.html.heex

@@ -48,7 +48,7 @@
                 <td class="px-2 align-top"><pre>(<%= line.application || @app %>)</pre></td>
                 <td>
                   <pre><%= "#{sanitize_module(line.module)}.#{line.function}/#{line.arity}" %>
-                <%= "#{line.file}.#{line.line}" %></pre>
+                <%= if line.line, do: "#{line.file}:#{line.line}", else: "nofile" %></pre>
                 </td>
               </tr>
             </tbody>