Code.with_diagnostics/2 formats paths as relative (#12590)

* Code.with_diagnostics/2 formats paths as relative

* Fix in :elixir_errors instead

* Fix it in parallel checker too

Author: sabiwara

lib/elixir/lib/kernel/parallel_compiler.ex

@@ -632,11 +632,11 @@ defmodule Kernel.ParallelCompiler do
         spawn_workers(queue, spawned, waiting, files, result, warnings, errors, state)
 
       {:diagnostic, %{severity: :warning} = diagnostic} ->
-        warnings = [diagnostic | warnings]
+        warnings = [Module.ParallelChecker.format_diagnostic_file(diagnostic) | warnings]
         wait_for_messages(queue, spawned, waiting, files, result, warnings, errors, state)
 
       {:diagnostic, %{severity: :error} = diagnostic} ->
-        errors = [diagnostic | errors]
+        errors = [Module.ParallelChecker.format_diagnostic_file(diagnostic) | errors]
         wait_for_messages(queue, spawned, waiting, files, result, warnings, errors, state)
 
       {:file_ok, child_pid, ref, file, lexical} ->

lib/elixir/lib/module/parallel_checker.ex

@@ -169,6 +169,7 @@ defmodule Module.ParallelChecker do
   defp collect_results(count, diagnostics) do
     receive do
       {:diagnostic, diagnostic} ->
+        diagnostic = format_diagnostic_file(diagnostic)
         collect_results(count, [diagnostic | diagnostics])
 
       {__MODULE__, _module, new_diagnostics} ->
@@ -287,6 +288,11 @@ defmodule Module.ParallelChecker do
     end
   end
 
+  @doc false
+  def format_diagnostic_file(%{file: file} = diagnostic) do
+    %{diagnostic | file: file && Path.absname(file)}
+  end
+
   ## Warning helpers
 
   defp group_warnings(warnings) do

lib/elixir/src/elixir_errors.erl

@@ -38,7 +38,7 @@ print_diagnostic(#{severity := Severity, message := Message, stacktrace := Stack
 emit_diagnostic(Severity, Position, File, Message, Stacktrace) ->
   Diagnostic = #{
     severity => Severity,
-    file => if File =:= nil -> nil; true -> filename:absname(File) end,
+    file => File,
     position => Position,
     message => unicode:characters_to_binary(Message),
     stacktrace => Stacktrace

lib/elixir/test/elixir/code_test.exs

@@ -198,6 +198,27 @@ defmodule CodeTest do
       :code.purge(CodeTest.CheckerWarning)
       :code.delete(CodeTest.CheckerWarning)
     end
+
+    test "formats diagnostic file paths as relatives" do
+      {_, diagnostics} =
+        Code.with_diagnostics(fn ->
+          try do
+            Code.eval_string("x", [])
+          rescue
+            e -> e
+          end
+        end)
+
+      assert [
+               %{
+                 message: "undefined variable \"x\"",
+                 position: 1,
+                 file: "nofile",
+                 stacktrace: [],
+                 severity: :error
+               }
+             ] = diagnostics
+    end
   end
 
   describe "eval_quoted/1" do