[ruby/error_highlight] Handle very long lines

https://github.com/ruby/error_highlight/commit/383490a4b4

1 files changed, 43 insertions, 0 deletions

diff --git a/lib/error_highlight/formatter.rb b/lib/error_highlight/formatter.rb
index 20ca78d468..b4fce93e55 100644
--- a/lib/error_highlight/formatter.rb
+++ b/lib/error_highlight/formatter.rb
@@ -3,6 +3,8 @@ module ErrorHighlight
     def self.message_for(spot)
       # currently only a one-line code snippet is supported
       if spot[:first_lineno] == spot[:last_lineno]
+        spot = truncate(spot)
+
         indent = spot[:snippet][0...spot[:first_column]].gsub(/[^\t]/, " ")
         marker = indent + "^" * (spot[:last_column] - spot[:first_column])
 
@@ -11,6 +13,47 @@ module ErrorHighlight
         ""
       end
     end
+
+    def self.viewport_size
+      Ractor.current[:__error_highlight_viewport_size__] || terminal_columns
+    end
+
+    def self.viewport_size=(viewport_size)
+      Ractor.current[:__error_highlight_viewport_size__] = viewport_size
+    end
+
+    private
+    
+    def self.truncate(spot)
+      ellipsis = '...'
+      snippet = spot[:snippet]
+      diff = snippet.size - (viewport_size - ellipsis.size)
+
+      # snippet fits in the terminal
+      return spot if diff.negative?
+
+      if spot[:first_column] < diff
+        snippet = snippet[0...snippet.size - diff]
+        {
+          **spot,
+          snippet: snippet + ellipsis + "\n",
+          last_column: [spot[:last_column], snippet.size].min
+        }
+      else
+        {
+          **spot,
+          snippet: ellipsis + snippet[diff..-1],
+          first_column: spot[:first_column] - (diff - ellipsis.size),
+          last_column: spot[:last_column] - (diff - ellipsis.size)
+        }
+      end
+    end
+    
+    def self.terminal_columns
+      # lazy load io/console in case viewport_size is set
+      require "io/console"
+      IO.console.winsize[1]
+    end
   end
 
   def self.formatter