753996 - Functions are inconsistently unwrapped for error messages

Status: RESOLVED INVALID

(Core :: JavaScript Engine, defect)

Description

[Steve Fink [:sfink] [:s:]]

When throwing an Error whose message contains the name of a function, the JS
engine calls js_ValueToFunction to produce the function name to include in the
message. js_ValueToFunction does not unwrap its argument. So if the function is
actually a wrapper, then js_ValueToFunction will throw a TypeError ("X is not a
function"). Confusingly, this TypeError uses the decompiler, which *will*
unwrap the object to get the wrapped function name out, so the final error will
look something like "SomeFunction() is not a function".)

Either neither or both should unwrap.

Comment 1

[Steve Fink [:sfink] [:s:]]

We've fixed this in various ways by now.