From 449afb84fffb5aff6581817cdf9f359f24cc9257 Mon Sep 17 00:00:00 2001
From: schneems <richard.schneeman+foo@gmail.com>
Date: Wed, 18 May 2022 12:06:06 -0700
Subject: [PATCH] [close #31] Annotate syntax error without require

As pointed out in #31 the current version of dead_end only works if the developer requires dead_end and then invokes `require`. This PR takes advantage of this change in Ruby 3.2 https://github.com/ruby/ruby/pull/5516 to modify the `SyntaxError` directly.

This behavior will only be fixed for Ruby 3.2+

Additionally we are still not able to handle the case where a program is streamed to ruby and does not exist on disk:

```
$ echo "def foo" | ruby
```

As the SyntaxError does not provide us with the contents of the script.

```
$ echo "def foo" | ruby
-:1: syntax error, unexpected end-of-input
def foo
```
---
 CHANGELOG.md             |  2 +
 lib/dead_end/core_ext.rb | 80 ++++++++++++++++++++++++++--------------
 2 files changed, 54 insertions(+), 28 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a27b3ca..35e59a5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## HEAD (unreleased)
 
+- Support Ruby 3.2 integration with SyntaxError (https://github.com/zombocom/dead_end/pull/139)
+
 ## 3.1.2
 
 - Fixed internal class AroundBlockScan, minor changes in outputs (https://github.com/zombocom/dead_end/pull/131)
diff --git a/lib/dead_end/core_ext.rb b/lib/dead_end/core_ext.rb
index 2886785..d91abcf 100644
--- a/lib/dead_end/core_ext.rb
+++ b/lib/dead_end/core_ext.rb
@@ -1,35 +1,59 @@
 # frozen_string_literal: true
 
-# Monkey patch kernel to ensure that all `require` calls call the same
-# method
-module Kernel
-  module_function
-
-  alias_method :dead_end_original_require, :require
-  alias_method :dead_end_original_require_relative, :require_relative
-  alias_method :dead_end_original_load, :load
-
-  def load(file, wrap = false)
-    dead_end_original_load(file)
-  rescue SyntaxError => e
-    DeadEnd.handle_error(e)
-  end
+if SyntaxError.new.respond_to?(:detailed_message)
+  require "stringio"
 
-  def require(file)
-    dead_end_original_require(file)
-  rescue SyntaxError => e
-    DeadEnd.handle_error(e)
-  end
+  SyntaxError.prepend Module.new {
+    def detailed_message(highlight: nil, **)
+      message = super
+
+      if (file = PathnameFromMessage.new(e.message, io: io).call.name)
+        io = StringIO.new
+        DeadEnd.call(
+          io: io,
+          source: file.read,
+          filename: file
+        )
+        annotation = io.string
+
+        annotation + message
+      else
+        message
+      end
+    end
+  }
+else
+  # Monkey patch kernel to ensure that all `require` calls call the same
+  # method
+  module Kernel
+    module_function
+
+    alias_method :dead_end_original_require, :require
+    alias_method :dead_end_original_require_relative, :require_relative
+    alias_method :dead_end_original_load, :load
+
+    def load(file, wrap = false)
+      dead_end_original_load(file)
+    rescue SyntaxError => e
+      DeadEnd.handle_error(e)
+    end
+
+    def require(file)
+      dead_end_original_require(file)
+    rescue SyntaxError => e
+      DeadEnd.handle_error(e)
+    end
 
-  def require_relative(file)
-    if Pathname.new(file).absolute?
-      dead_end_original_require file
-    else
-      relative_from = caller_locations(1..1).first
-      relative_from_path = relative_from.absolute_path || relative_from.path
-      dead_end_original_require File.expand_path("../#{file}", relative_from_path)
+    def require_relative(file)
+      if Pathname.new(file).absolute?
+        dead_end_original_require file
+      else
+        relative_from = caller_locations(1..1).first
+        relative_from_path = relative_from.absolute_path || relative_from.path
+        dead_end_original_require File.expand_path("../#{file}", relative_from_path)
+      end
+    rescue SyntaxError => e
+      DeadEnd.handle_error(e)
     end
-  rescue SyntaxError => e
-    DeadEnd.handle_error(e)
   end
 end