Fix depwarn on 0.5

[yuyichao]

String, Symbol, precision(BigFloat)
Also fix an incorrect use of unsafe_convert.

Requires a new tag of Compat.
Also includes #260

Requires JuliaLang/Compat.jl#192

[stevengj]

Presumably we should wait until the necessary version of Compat is tagged?

[yuyichao]

Correct. I'm just not sure what's the status of JuliaLang/Compat.jl#192 .

[yuyichao]

General comment about passing julia object to C.
If you want to pass an julia object v to C in the same format it would have been passed in ccall as an argument of type T with explicit control of the object lifetime, the correct way to do this is (with the exception if T is Any since it is handled specially),

root = Base.cconvert(T, v) # this object controls the lifetime
cobj = Base.unsafe_convert(T, v) # this is the C value

The name of the pointer field comes from pointerfree. I can rename it to GC root if it's more clear.

[stevengj]

Oh, right. The cconvert function is very confusingly named, because I keep expecting it to act like convert; it's weird that cconvert(T, v) does not produce an object of type T. Maybe gcroot would be a more descriptive name.

[yuyichao]

Maybe gcroot would be a more descriptive name.

gc_convert ;-p (not sure if it actually worth changing the name though....)

Another note is that pointer should generally be avoided whenever possible. It is usually only necessary for interacting with C code (ok, I admit I've used it to workaround LLVM vectorization issue......) and in such case the cconvert, unsafe_convert is much safer (despite possibly confusing names.....) and should automatically happen for ccall.

[yuyichao]

It's weird that cconvert(T, v) does not produce an object of type T.

It's true that it can return whatever type it feels like as long as it keeps the result of unsafe_convert on the same type alive. This indeed doesn't sound like what a *convert should do (except that it is part of the full conversion (cconvert + unsafe_convert) to a C object) so I now see why it is confusing.......... (started in 0.4 time, I've never seen the old interface and have naturally accepted the new one....)

[yuyichao]

Updated.

There is one API change here. I take this as it doesn't matter....

[coveralls]

Coverage decreased (-0.5%) to 58.895% when pulling baa6180 on yuyichao:0.5-deps into eb8d70a on stevengj:master.

[stevengj]

Yeah, using ByteString there on 0.5 should be fine.

[stevengj]

Travis failure:

ERROR: LoadError: PyError (:PyObject_Call) <type 'exceptions.TypeError'>
TypeError('type() argument 1 must be string, not unicode',)

Probably the string conversion needs to be:

function PyObject(s::AbstractString)
    sb = String(s)
    if pyunicode_literals || !isascii(sb)
        PyObject(@pycheckn ccall(@pysym(PyUnicode_DecodeUTF8),
                                 PyPtr, (Ptr{UInt8}, Int, Ptr{UInt8}),
                                 sb, sizeof(sb), C_NULL))
    else
        PyObject(@pycheckn ccall(@pysym(PyString_FromStringAndSize),
                                 PyPtr, (Ptr{UInt8}, Int), sb, sizeof(sb)))
    end
end

and you can get rid of PyObject(::String).

[yuyichao]

............ python unicode coupled with julia string change ...........

Yeah, I only tested on python3.... I'll fix it soon.

[yuyichao]

Done

[coveralls]

Coverage decreased (-0.07%) to 59.354% when pulling 6ff7415 on yuyichao:0.5-deps into eb8d70a on stevengj:master.

[yuyichao]

ping.

[stevengj]

Thanks!