Bug #19116: Array#pack is broken for long strings in buffer

• Status: Closed
• Assignee: -
• Target version: -
• Backport: 2.7: REQUIRED, 3.0: REQUIRED, 3.1: DONE

[jemmai (Jemma Issroff)]

Array#pack is broken for long strings in the buffer.

See this failure:

n = [ 65, 66, 67 ]
super_long_string = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
assert_equal(n.pack("@3ccc", buffer: super_long_string), "aaaABC")

# => <internal:pack>:144:in `pack': can't set length of shared string (RuntimeError)
	from (irb):6:in `<main>'
	from /opt/rubies/3.1.2/lib/ruby/gems/3.1.0/gems/irb-1.4.1/exe/irb:11:in `<top (required)>'
	from /opt/rubies/3.1.2/bin/irb:25:in `load'
	from /opt/rubies/3.1.2/bin/irb:25:in `<main>'

[peterzhu2118 (Peter Zhu)]

• Backport changed from 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN to 2.7: REQUIRED, 3.0: REQUIRED, 3.1: REQUIRED

[jemmai (Jemma Issroff)]

Fix is in this PR

[jemmai (Jemma Issroff)]

• Status changed from Open to Closed

Applied in changeset git|199b59f065ce6f1c13b8424f35a70c513523211b.

---

Fix bug in array pack with shared strings

If string literals are long and they become shared, we need to make them
independent before we can write to them. [Bug #19116]

[nagachika (Tomoyuki Chikanaga)]

• Backport changed from 2.7: REQUIRED, 3.0: REQUIRED, 3.1: REQUIRED to 2.7: REQUIRED, 3.0: REQUIRED, 3.1: DONE

ruby_3_1 db1aa39ffcaa5b9f062639eb30c76959f4607a8e merged revision(s) 199b59f065ce6f1c13b8424f35a70c513523211b.