From ade8128a18ec3a053306e364e31687739de8c568 Mon Sep 17 00:00:00 2001
From: Alyssa Ross <hi@alyssa.is>
Date: Wed, 1 Feb 2017 18:30:55 +0000
Subject: [PATCH] formulary: handle ScriptError in formula

I added a new `FormulaUnreadableError` subclass of
`FormulaUnavailableError` so existing `rescue`s of
`FormulaUnavailableError` handle this as well.

The new subclass will output the name of the formula with the error
(because this isn't always obvious from the original exception message)
followed by the original error message.

Fixes #1927.
---
 Library/Homebrew/exceptions.rb           | 13 +++++++++++++
 Library/Homebrew/formulary.rb            |  6 +++++-
 Library/Homebrew/test/exceptions_test.rb |  5 +++++
 3 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/exceptions.rb b/Library/Homebrew/exceptions.rb
index c5d888d644..77da4489e8 100644
--- a/Library/Homebrew/exceptions.rb
+++ b/Library/Homebrew/exceptions.rb
@@ -131,6 +131,19 @@ class FormulaClassUnavailableError < FormulaUnavailableError
   end
 end
 
+class FormulaUnreadableError < FormulaUnavailableError
+  attr_reader :formula_error
+
+  def initialize(name, error)
+    super(name)
+    @formula_error = error
+  end
+
+  def to_s
+    "#{name}: " + formula_error.to_s
+  end
+end
+
 class TapFormulaAmbiguityError < RuntimeError
   attr_reader :name, :paths, :formulae
 
diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index 25df57cdc2..cf85ba03f6 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -22,7 +22,11 @@ class Formulary
 
     mod = Module.new
     const_set(namespace, mod)
-    mod.module_eval(contents, path)
+    begin
+      mod.module_eval(contents, path)
+    rescue ScriptError => e
+      raise FormulaUnreadableError.new(name, e)
+    end
     class_name = class_s(name)
 
     begin
diff --git a/Library/Homebrew/test/exceptions_test.rb b/Library/Homebrew/test/exceptions_test.rb
index 689531c6ee..e9fedef047 100644
--- a/Library/Homebrew/test/exceptions_test.rb
+++ b/Library/Homebrew/test/exceptions_test.rb
@@ -56,6 +56,11 @@ class ExceptionsTest < Homebrew::TestCase
       FormulaClassUnavailableError.new("foo", "foo.rb", "Foo", list).to_s
   end
 
+  def test_formula_unreadable_error
+    formula_error = LoadError.new("bar")
+    assert_equal "foo: bar", FormulaUnreadableError.new("foo", formula_error).to_s
+  end
+
   def test_tap_unavailable_error
     assert_equal "No available tap foo.\n", TapUnavailableError.new("foo").to_s
   end