Bug #17117: Corruption in ARGF.inplace

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 2.8.0dev (2020-08-11T19:09:12Z inplace-str-corrup.. 16d72713d2) [x86_64-darwin19]
• Backport: 2.5: REQUIRED, 2.6: REQUIRED, 2.7: REQUIRED

[peterzhu2118 (Peter Zhu)]

Extension string stored in ARGF.inplace is created using an api designed for C string constants to create a Ruby string that points at another Ruby string. When the original string is swept, the extension string gets corrupted.

Reproduction script (on MacOS):

#!/usr/bin/ruby -pi.bak

BEGIN {
  GC.start(full_mark: true)
  arr = []
  1000000.times do |x|
    arr << "fooo#{x}"
  end
}

puts "hello"

Fix PR on GitHub

Reproduction

1. Assuming you have the above script in a file called test.rb.
2. Create a file called foo.txt with contents foo.
3. Run ruby test.rb foo.txt.

Expected behaviour

foo.txt with contents hello\nfoo and foo.txt.bak with contents foo.

Actual behavior

foo.txt with contents hello\nfoo and foo.txto121 with contents foo.

[peterzhu2118 (Peter Zhu)]

• Description updated (diff)

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed
• Backport changed from 2.5: UNKNOWN, 2.6: UNKNOWN, 2.7: UNKNOWN to 2.5: REQUIRED, 2.6: REQUIRED, 2.7: REQUIRED