Backport #7671: Unexpected result of the Flip-Flop

• Status: Closed
• Assignee: usa (Usaku NAKAMURA)

[phasis68 (Heesob Park)]

Reported from http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/402825

C:\work>irb
irb(main):001:0> vs = (1..9).to_a
=> [1, 2, 3, 4, 5, 6, 7, 8, 9]
irb(main):002:0> v1 = vs.select { |n| if n==3..n==6 then 1 end }
=> [3, 4, 5, 6]
irb(main):003:0> v2 = vs.select { |n| if n==2..n==16 then 1 end }
=> [2, 3, 4, 5, 6, 7, 8, 9]
irb(main):004:0> v3 = vs.select { |n| if n==3..n==6 then 1 end }
=> [1, 2, 3, 4, 5, 6]

v1 and v3 use some condition , return value is different.

This bug is due to changeset r38292 and only occurs on the irb session.

Here is a patch:
diff --git a/compile.c b/compile.c.new
index db060e7..e644390 100644
--- a/compile.c
+++ b/compile.c.new
@@ -5057,7 +5057,7 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR *ret, NODE * node, int poped)

if (!data) data = iseq->compile_data;
cnt = data->flip_cnt++ + DEFAULT_SPECIAL_VAR_COUNT;

• key = INT2FIX(cnt);

• key = LL2NUM(cnt+(VALUE)iseq);

  ADD_INSN2(ret, nd_line(node), getspecial, key, INT2FIX(0));
  ADD_INSNL(ret, nd_line(node), branchif, lend);

[nobu (Nobuyoshi Nakada)]

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

This issue was solved with changeset r38739.
Heesob, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

vm_core.h: flip_cnt in rb_iseq_t

• vm_core.h (rb_iseq_t): move flip_cnt from struct iseq_compile_data,
  because it has same life span as enclosing iseq. [Bug #7671]
  [ruby-core:51296]

[nobu (Nobuyoshi Nakada)]

• Tracker changed from Bug to Backport
• Project changed from Ruby master to Backport193
• Status changed from Closed to Assigned
• Assignee set to usa (Usaku NAKAMURA)

[usa (Usaku NAKAMURA)]

• Status changed from Assigned to Closed

This issue was solved with changeset r38781.
Heesob, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

merge revision(s) 38739: [Backport #7671]

* vm_core.h (rb_iseq_t): move flip_cnt from struct iseq_compile_data,
  because it has same life span as enclosing iseq.  [Bug #7671]
  [ruby-core:51296]