JDK-8035312 : push() on frozen array increases its length property
  • Type: Bug
  • Component: core-libs
  • Sub-Component: jdk.nashorn
  • Affected Version: 8u40
  • Priority: P3
  • Status: Resolved
  • Resolution: Fixed
  • OS: generic
  • CPU: generic
  • Submitted: 2014-02-19
  • Updated: 2015-06-04
  • Resolved: 2014-11-12
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8u40Fixed 9 b40Fixed
x = [1, 2, 3]; Object.freeze(x); x.push(4);
<shell>:1 TypeError: Cannot set property "3" of frozen array
jjs> x
jjs> x.length

x.length should still be 3.
Turns out to be quite a bit bigger than expected. This involves length on various ScriptObject and array operations implicit and explicit. Writing an exhaustive unit test as part of the fix

Taking over this to balance bug load.

related issue: var arr = []; Object.defineProperty(arr, "length", { writable: false }); try { arr.push("foo"); } catch(e) { } print(arr.length); print(arr[0]); Expected output: 0 foo Actual output: 1 foo "length" should not be modified because it is non-writable. But element should be pushed because "push" first pushes elements and the sets the "length" at the end per spec. http://es5.github.io/#x15.4.4.7