[ruby/irb] Centralize coloring control (https://github.com/ruby/irb/pull/374)

* Use colorable: argument as the only coloring control

* Centalize color controling logic at Color.colorable?

There are 2 requirements for coloring output:

1. It's supported on the platform
2. The user wants it: `IRB.conf[:USE_COLORIZE] == true`

Right now we check 1 and 2 separately whenever we colorize things.
But it's error-prone because while 1 is the default of `colorable`
parameter, 2 always need to manually checked. When 2 is overlooked, it
causes issues like https://github.com/ruby/irb/pull/362

And there's 0 case where we may want to colorize even when the user
disables it. So I think we should merge 2 into `Color.colorable?` so it
can be automatically picked up.

* Add tests for all inspect modes

* Simplify inspectors' coloring logic

* Replace use_colorize? with Color.colorable?

* Remove Context#use_colorize cause it's redundant

https://github.com/ruby/irb/commit/1c53023ac4

1 files changed, 2 insertions, 10 deletions

diff --git a/lib/irb/inspector.rb b/lib/irb/inspector.rb
index 8c37c0f174..d8c0ba90cf 100644
--- a/lib/irb/inspector.rb
+++ b/lib/irb/inspector.rb
@@ -108,18 +108,10 @@ module IRB # :nodoc:
 
   Inspector.def_inspector([false, :to_s, :raw]){|v| v.to_s}
   Inspector.def_inspector([:p, :inspect]){|v|
-    result = v.inspect
-    if IRB.conf[:MAIN_CONTEXT]&.use_colorize? && Color.inspect_colorable?(v)
-      result = Color.colorize_code(result)
-    end
-    result
+    Color.colorize_code(v.inspect, colorable: Color.colorable? && Color.inspect_colorable?(v))
   }
   Inspector.def_inspector([true, :pp, :pretty_inspect], proc{require_relative "color_printer"}){|v|
-    if IRB.conf[:MAIN_CONTEXT]&.use_colorize?
-      IRB::ColorPrinter.pp(v, '').chomp
-    else
-      v.pretty_inspect.chomp
-    end
+    IRB::ColorPrinter.pp(v, '').chomp
   }
   Inspector.def_inspector([:yaml, :YAML], proc{require "yaml"}){|v|
     begin