From: nagachika00@... Date: 2017-12-24T18:59:59+00:00 Subject: [ruby-core:84430] [Ruby trunk Bug#13949] String#unpack with 'M' directive can create strings with wrong code range Issue #13949 has been updated by nagachika (Tomoyuki Chikanaga). Backport changed from 2.3: REQUIRED, 2.4: REQUIRED to 2.3: REQUIRED, 2.4: DONE ruby_2_4 r61454 merged revision(s) 60059. ---------------------------------------- Bug #13949: String#unpack with 'M' directive can create strings with wrong code range https://bugs.ruby-lang.org/issues/13949#change-68626 * Author: nirvdrum (Kevin Menard) * Status: Closed * Priority: Normal * Assignee: * Target version: * ruby -v: ruby 2.4.2p198 (2017-09-14 revision 59899) [x86_64-linux] * Backport: 2.3: REQUIRED, 2.4: DONE ---------------------------------------- I've noticed that `String#unpack` with the `'M'` directive can create strings that should be `CR_7BIT` as `CR_VALID`. The issue appears to have been introduced in r30542, which assumes that all `ASCII-8BIT` strings must be `CR_VALID`. It's possible this was correct back during Ruby 1.9.3 development and just wasn't updated. I'm not familiar enough with the history to tell. A simple reproduction showing the issue is: ``` res = '0123456789=\n'.unpack('M').first p res p res.encoding p res.bytes p res.ascii_only? puts packed = res.bytes.pack('c*') p packed p packed.encoding p packed.bytes p packed.ascii_only? ``` This yields the following output: ``` "0123456789=\\n" # [48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 61, 92, 110] false "0123456789=\\n" # [48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 61, 92, 110] true ``` Both strings have exactly the same contents with the same encoding. But, depending on how you construct them, one is consider to be `CR_7BIT` value (indicated by the `String#ascii_only?` output), and one is considered to be `CR_VALID`. I believe `CR_7BIT` is the correct code range value in this situation. -- https://bugs.ruby-lang.org/ Unsubscribe: