[ruby-core:106731] [Ruby master Bug#18415] String#rpartition is not sufficiently greedy compared to String#partition

Issue #18415 has been updated by sawa (Tsuyoshi Sawada).


I think the actual result is expected. It is `partition`'s responsibility to match the left-most position possible, and it is `+`'s responsibility to match as long as possible from that position. Likewise, it is `rpartition`'s responsibility to match the right-most position possible, and it is `+`'s responsibility to match as long as possible from that position. `["...99", "9", "..."]` is the correct result of this.

If you want to match `999` with `rpartition`, you need to do something like:

```ruby
"...999...".rpartition(/(?<!\d)\d+/)
# => ["...", "999", "..."]
```

----------------------------------------
Bug #18415: String#rpartition is not sufficiently greedy compared to String#partition
https://bugs.ruby-lang.org/issues/18415#change-95415

* Author: jdashton (J Daniel Ashton)
* Status: Open
* Priority: Normal
* ruby -v: ruby 3.1.0preview1 (2021-11-09 master 5a3b2e6141) [x86_64-darwin21]
* Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
----------------------------------------
``` ruby
3.1.0-preview1 :043 > "...999...".partition /\d+/
 => ["...", "999", "..."] 
3.1.0-preview1 :044 > "...999...".rpartition /\d+/
 => ["...99", "9", "..."] 

```

Using the regex /\d+/, `partition` gives you all consecutive digits. However, `rpartition` gives only the last digit.




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