Fix caller filter to ignore rubygems

lib/rspec/support/caller_filter.rb

@@ -18,6 +18,14 @@ class CallerFilter
 
     LIB_REGEX = %r{/lib/rspec/(#{(RSPEC_LIBS + ADDITIONAL_TOP_LEVEL_FILES).join('|')})(\.rb|/)}
 
+    # rubygems/core_ext/kernel_require.rb isn't actually part of rspec (obviously) but we want
+    # it ignored when we are looking for the first meaningful line of the backtrace outside
+    # of RSpec. It can show up in the backtrace as the immediate first caller
+    # when `CallerFilter.first_non_rspec_line` is called from the top level of a required
+    # file, but it depends on if rubygems is loaded or not. We don't want to have to deal
+    # with this complexity in our `RSpec.deprecate` calls, so we ignore it here.
+    IGNORE_REGEX = Regexp.union(LIB_REGEX, "rubygems/core_ext/kernel_require.rb")
+
     if RUBY_VERSION >= '2.0.0'
       def self.first_non_rspec_line
         # `caller` is an expensive method that scales linearly with the size of
@@ -37,7 +45,7 @@ def self.first_non_rspec_line
           stack = caller(i, increment)
           raise "No non-lib lines in stack" unless stack
 
-          line = stack.find { |l| l !~ LIB_REGEX }
+          line = stack.find { |l| l !~ IGNORE_REGEX }
 
           i         += increment
           increment *= 2 # The choice of two here is arbitrary.
@@ -49,7 +57,7 @@ def self.first_non_rspec_line
       # Earlier rubies do not support the two argument form of `caller`. This
       # fallback is logically the same, but slower.
       def self.first_non_rspec_line
-        caller.find { |line| line !~ LIB_REGEX }
+        caller.find { |line| line !~ IGNORE_REGEX }
       end
     end
   end

spec/rspec/support/caller_filter_spec.rb

@@ -15,17 +15,12 @@ def ruby_files_in_lib(lib)
 
     describe "the filtering regex" do
       def unmatched_from(files)
-        files.reject { |file| file.match(CallerFilter::LIB_REGEX) }
+        files.reject { |file| file.match(CallerFilter::IGNORE_REGEX) }
       end
 
       %w[ core mocks expectations support ].each do |lib|
         it "matches all ruby files in rspec-#{lib}" do
-          files     = ruby_files_in_lib(lib)
-
-          # We don't care about this file -- it only has a single require statement
-          # and won't show up in any backtraces.
-          files.reject! { |file| file.end_with?('lib/rspec-expectations.rb') }
-
+          files = ruby_files_in_lib(lib)
           expect(unmatched_from files).to eq([])
         end
       end
@@ -38,6 +33,31 @@ def unmatched_from(files)
 
         expect(unmatched_from files).to eq(files)
       end
+
+      def in_rspec_support_lib(name)
+        root = File.expand_path("../../../../lib/rspec/support", __FILE__)
+        dir = "#{root}/#{name}"
+        FileUtils.mkdir(dir)
+        yield dir
+      ensure
+        FileUtils.rm_rf(dir)
+      end
+
+      it 'does not match rubygems lines from `require` statements' do
+        require 'rubygems' # ensure rubygems is laoded
+
+        in_rspec_support_lib("test_dir") do |dir|
+          File.open("#{dir}/file.rb", "w") do |file|
+            file.write("$_caller_filter = RSpec::CallerFilter.first_non_rspec_line")
+          end
+
+          $_caller_filter = nil
+
+          expect {
+            require "rspec/support/test_dir/file"
+          }.to change { $_caller_filter }.to(include "#{__FILE__}:#{__LINE__ - 1}")
+        end
+      end
     end
   end
 end