Feature #9143: Optimize CSV to share hash key objects between rows

• Status: Closed
• Priority: Normal
• Assignee: JEG2 (James Gray)
• Target version: -

[avit (Andrew Vit)]

Currently, when CSV headers are strings, then each row receives a copy of the strings for hash keys. This patch is an optimization to share the same frozen string keys between all rows.

Please verify: in the implementation of Hash::[], are strings the only object that is dup'd, or should other types be frozen so they aren't copied for each row too?

[avit (Andrew Vit)]

Note, this can be worked around by doing csv.header_converters << proc{|h| h.freeze } but I think there should be some built-in optimization for this.

[nobu (Nobuyoshi Nakada)]

=begin
You can use (({assert_instance_of})) and (({assert_same})).
=end

[avit (Andrew Vit)]

• File csv-freeze-headers-2.patch csv-freeze-headers-2.patch added

Thanks nobu, I write too much RSpec lately.

Updated patch attached: I also added freeze in Row#initialize, not sure if both places are needed, or which is better. Please review.

[nobu (Nobuyoshi Nakada)]

assert_predicate(string_key, :frozen?) will show better message when it fails.

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Assigned
• Assignee set to JEG2 (James Gray)

[JEG2 (James Gray)]

• Status changed from Assigned to Closed
• % Done changed from 50 to 100