[ruby/irb] Avoid completing empty input

(https://github.com/ruby/irb/pull/832)

The candidate list for empty input is all methods + all variables +
all constants + all keywords. It's a long list that is not useful.

https://github.com/ruby/irb/commit/812dc2df7b

1 files changed, 7 insertions, 1 deletions

diff --git a/lib/irb/completion.rb b/lib/irb/completion.rb
index af3b69eb27..7b9c1bbbdd 100644
--- a/lib/irb/completion.rb
+++ b/lib/irb/completion.rb
@@ -406,7 +406,13 @@ module IRB
         else
           select_message(receiver, message, candidates.sort)
         end
-
+      when /^\s*$/
+        # empty input
+        if doc_namespace
+          nil
+        else
+          []
+        end
       else
         if doc_namespace
           vars = (bind.local_variables | bind.eval_instance_variables).collect{|m| m.to_s}