Backport #5124: foo = [*bar] implies foo.equal?(bar)

• Status: Closed
• Priority: Normal
• Assignee: naruse (Yui NARUSE)

[adgar (Michael Edgar)]

I just ran into this as a result of some slightly sloppy coding, but it did disagree with my internal assumptions.

Normally, I expect the Array literal syntax to create a new object, every time. So when I rewrote some code and ended up with something similar to the following, my tests broke, and I'm not sure that's how it should be. Here's the reduced test case:

some_ary = [1, 2, 3]
bar = [*some_ary]
bar << 4

p bar

[1, 2, 3, 4]
p some_ary
[1, 2, 3, 4]

I see it's clearly taking an opportunity for optimization, so I'm more than happy to hear that as a reason for rejecting this. It does warrant documentation somewhere, though, I'd say. Not sure where that documentation would go.

[nobu (Nobuyoshi Nakada)]

• Category set to core
• Status changed from Open to Assigned
• Assignee set to ko1 (Koichi Sasada)
• Target version set to 1.9.3

It's easy to fix that splatarray always makes a new array, but I'm uncertain of its flag.

[kosaki (Motohiro KOSAKI)]

Sasada-san, ping?

[ko1 (Koichi Sasada)]

• ruby -v changed from ruby 1.9.2p188 (2011-03-28 revision 31204) [x86_64-darwin10.7.0] to -

Hi,

Sorry for late response.

(2011/07/31 6:48), Nobuyoshi Nakada wrote:

It's easy to fix that splatarray always makes a new array, but I'm uncertain of its flag.

Could you apply your patch if there is no failure on test-all/ruby-spec?

--
// SASADA Koichi at atdot dot net

[ko1 (Koichi Sasada)]

• Status changed from Assigned to Feedback

nobu: ping.

[nobu (Nobuyoshi Nakada)]

• Tracker changed from Bug to Backport
• Project changed from Ruby master to Backport193
• Category deleted (core)
• Target version deleted (1.9.3)

[nobu (Nobuyoshi Nakada)]

• Status changed from Feedback to Assigned
• Assignee changed from ko1 (Koichi Sasada) to naruse (Yui NARUSE)

[naruse (Yui NARUSE)]

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r36228.
Michael, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

merge revision(s) 34633: [Backport #5124]

* insns.def (splatarray): make new array if flag is set.

* compile.c (iseq_compile_each): make new array with
  splat. [ruby-core:21901][Feature #1125]