Handle negativity in Pry::Code#take_lines [Fixes #886]

2 files changed, 7 insertions, 1 deletions

diff --git a/lib/pry/code.rb b/lib/pry/code.rb
index 82fe05d9..c8c9c52d 100644
--- a/lib/pry/code.rb
+++ b/lib/pry/code.rb
@@ -197,7 +197,7 @@ class Pry
         if start_line >= 0
           @lines.index { |loc| loc.lineno >= start_line } || @lines.length
         else
-          @lines.length + start_line
+          [@lines.length + start_line, 0].max
         end
 
       alter do
diff --git a/spec/commands/hist_spec.rb b/spec/commands/hist_spec.rb
index ca01adc8..0b5ea252 100644
--- a/spec/commands/hist_spec.rb
+++ b/spec/commands/hist_spec.rb
@@ -79,6 +79,12 @@ describe "hist" do
     out.should =~ /x\n\d+:.*y\n\d+:.*z/
   end
 
+  it "should start from beginning if tail number is longer than history" do
+    @hist.push 'Hyacinth'
+    out = @t.eval 'hist --tail'
+    out.should =~ /Hyacinth/
+  end
+
   it 'should apply --tail after --grep' do
     @hist.push "print 1"
     @hist.push "print 2"