Clojure

clojure.string/trim doesn't trim null character

Details

  • Type: Defect Defect
  • Status: Closed Closed
  • Priority: Minor Minor
  • Resolution: Declined
  • Affects Version/s: Release 1.6
  • Fix Version/s: None
  • Component/s: None
  • Labels:

Description

CLJ-935 changed clojure.string/trim to not trim all the characters less than or equal to \u0020 as Java does.

I noticed this because base64 uses null characters to pad the end of encoding blocks.

Clojure 1.6.0's trim leaves the null character in:
user=> (.length (clojure.string/trim "\u0000"))
1

java.lang.String's trim takes it out:
user=> (.length (.trim "\u0000"))
0

Here are the first 21 unicode characters and what Character/isWhitespace says about them.

(dotimes [n 0x20] (printf "
u%04x - %b\n" n (Character/isWhitespace n)))
\u0000 - false
\u0001 - false
\u0002 - false
\u0003 - false
\u0004 - false
\u0005 - false
\u0006 - false
\u0007 - false
\u0008 - false
\u0009 - true
\u000a - true
\u000b - true
\u000c - true
\u000d - true
\u000e - false
\u000f - false
\u0010 - false
\u0011 - false
\u0012 - false
\u0013 - false
\u0014 - false
\u0015 - false
\u0016 - false
\u0017 - false
\u0018 - false
\u0019 - false
\u001a - false
\u001b - false
\u001c - true
\u001d - true
\u001e - true
\u001f - true

Activity

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Alex Miller added a comment -

The choice was made in CLJ-935 to consistently define whitespace as Character.isWhitespace() across trim, triml, and trimr. There are many possible ways to define "space" (at least two as we see here). If your trimming needs differ from the standard library, then you'll probably need to define your own functions to trim your data. You can still use Java interop to call String.trim() directly if that happens to match your needs.

Show
Alex Miller added a comment - The choice was made in CLJ-935 to consistently define whitespace as Character.isWhitespace() across trim, triml, and trimr. There are many possible ways to define "space" (at least two as we see here). If your trimming needs differ from the standard library, then you'll probably need to define your own functions to trim your data. You can still use Java interop to call String.trim() directly if that happens to match your needs.
Hide
Ryan Fowler added a comment -

Indeed, it's an easy workaround to use Java interop once you figure out what your problem is.

It's just unintuitive that the character generally used for string termination isn't trimmed by clojure.string/trim.

Show
Ryan Fowler added a comment - Indeed, it's an easy workaround to use Java interop once you figure out what your problem is. It's just unintuitive that the character generally used for string termination isn't trimmed by clojure.string/trim.

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Dates

  • Created:
    Updated:
    Resolved: