508557 - delete should not throw an exception on unresolvable references

Status: RESOLVED FIXED

(Rhino Graveyard :: Core, defect)

Description

[rspeyer]

User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_5_7; en-US) AppleWebKit/532.0 (KHTML, like Gecko) Chrome/3.0.196 Safari/532.0
Build Identifier: Rhino 1.7 release 2 2009 03 22

It should just return true, as per 11.4.1 of the spec

Reproducible: Always

Actual Results:  
js> delete somethingNotDefined
js: "<stdin>", line 2: uncaught JavaScript runtime exception: TypeError: Cannot delete property "somethingNotDefined" of null
	at <stdin>:2


Expected Results:  
js> delete somethingNotDefined
true

Comment 1

[rspeyer]

Attachment: made delete simply return true given an unresolvable reference

As per 11.4.1 of the spec

Comment 2

[Norris Boyd]

SpiderMonkey throws an error on "delete null.p", which I think is correct from 11.4.1 since it's supposed to resolve the UnaryExpression "null.p", which should throw an exception. With the proposed change, "delete null.p" just resolves to true.

Comment 3

[rspeyer]

Hmm, we need some way to distinguish between the unresolvable reference that results from looking up an absent identifier, and a property access reference on a null or undefined base value.

Comment 4

[Hannes Wallnoefer]

Attachment: Make delete return true on undefined names

Adds a boolean parameter to ScriptRuntime.delete() to tell whether unresolved reference should be accepted. The change in Codegen was relatively straightforward because we have access to the AST tree, but for the Interpreter I had to introduce a new bytecode, Icode_DELNAME.

Comment 5

[Hannes Wallnoefer]

I committed a slightly modified version of the patch.

https://github.com/mozilla/rhino/commit/adad88afabf6d34757e99ca730f65b4872ead96d