Ruby string::include? bug (only in docker)

[amasad]

I'm still not certain as to why this is happening but string::include? in some cases is returning true where it should be false.

To repro just run the following:

docker run ruby:2.3-alpine ruby -e 'puts "xxxAy".include? "Azzz"'

Here are some more test cases:

"12390".include? "9567"

"xyzab".include? "aklm" 

[yosifkit]

I made a quick example (in some limited tests, it seems to happen with 4 chars in the second string, if it starts with the second to last letter, and 3 chars if it starts the last letter):

$ docker run -it --rm ruby:alpine ruby -e '(1..20).each { |i| str = "*" * i + "An"; print "#{i}: "; puts str.include? "Azzz"}'
1: false
2: false
3: true
4: true
5: true
6: true
7: true
8: true
9: true
10: true
11: true
12: true
13: true
14: true
15: true
16: true
17: true
18: true
19: true
20: true
$ docker run -it --rm ruby ruby -e '(1..20).each { |i| str = "*" * i + "An"; print "#{i}: "; puts str.include? "Azzz"}'
1: false
2: false
3: false
4: false
5: false
6: false
7: false
8: false
9: false
10: false
11: false
12: false
13: false
14: false
15: false
16: false
17: false
18: false
19: false
20: false

It seems to be specifically Alpine Linux related and happens in their package of ruby. 😕

$ docker run -it --rm alpine sh
/ # apk add --no-cache ruby
fetch http://dl-cdn.alpinelinux.org/alpine/v3.3/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.3/community/x86_64/APKINDEX.tar.gz
(1/10) Installing ncurses-terminfo-base (6.0-r6)
(2/10) Installing ncurses-terminfo (6.0-r6)
(3/10) Installing ncurses-libs (6.0-r6)
(4/10) Installing libedit (20150325.3.1-r3)
(5/10) Installing libffi (3.2.1-r2)
(6/10) Installing gdbm (1.11-r1)
(7/10) Installing gmp (6.1.0-r0)
(8/10) Installing yaml (0.1.6-r1)
(9/10) Installing ruby-libs (2.2.4-r0)
(10/10) Installing ruby (2.2.4-r0)
Executing busybox-1.24.1-r7.trigger
OK: 26 MiB in 21 packages
/ # ruby -e '(1..20).each { |i| str = "*" * i + "An"; print "#{i}: "; puts str.include? "A
zzz"}'
1: false
2: false
3: true
4: true
5: true
6: true
7: true
8: true
9: true
10: true
11: true
...

Maybe @ncopa would know more here?

[amasad]

Also repros in Busybox Ruby package, seems like they share the same library.

docker run amasad/busyruby ruby -e 'puts "xxxAy".include? "Azzz"'

[ncopa]

This is definitively a bug in musl. Fix is on its way.

[ncopa]

upstream fixes are:
http://git.musl-libc.org/cgit/musl/commit/?id=c718f9fc1b4bd913eff10d0c12763f90b2bc487c
http://git.alpinelinux.org/cgit/aports/commit/?h=3.3-stable&id=6c0da3533b15b9fc9ed614484de9b2097d278b1b

[andyshinn]

I'll rebuild images and open library PR shortly.