fix rational vs float comparisons (attempt 2)

[simonbyrne]

This fixes FloatingPoint vs Rational inequality comparisons (see #2960 and #8411), replacing #8463: unlike that attempt, it doesn't try to completely modify the whole dispatch system, so is much simpler, and less likely to break anything.

After this, the only remaining possibly inexact comparisons should be Rational vs MathConst.

[StefanKarpinski]

I guess I had better read this carefully but it looks pretty good at first impression.

[tkelman]

Linux and Win64 CI failures were unrelated, but Win32 looks like a legit issue:

exception on 2: ERROR: test error in expression: 1 / 3 < 1 // 3
InexactError()
 in decompose at hashing2.jl:127
 in anonymous at test.jl:83
 in do_test at test.jl:47
 in runtests at C:\projects\julia\test\testdefs.jl:5
 in anonymous at multi.jl:828
 in run_work_thunk at multi.jl:593
 in anonymous at task.jl:828
while loading numbers.jl, in expression starting on line 800

[simonbyrne]

It appears to be an existing bug in decompose. I'll push a fix.

[simonbyrne]

Okay, hopefully that fixes it. I've also added some extra tests to check decompose does the right thing.

[tkelman]

That worked on appveyor. I have no idea what's wrong with Linux Travis, I think someone will need to spend some time in a docker container or VM of Ubuntu 12.04 to try to reproduce whatever's happening there.

[simonbyrne]

I've managed to get an Ubuntu 12.04 VM running, but I get different errors on the tests:

    ....
     * socket
     * floatapprox
     * readdlm
Killed
make[1]: *** [all] Error 137
make: *** [testall] Error 2

[simonbyrne]

I also get a different on on collections:

    JULIA test/collections
     * collections
exception on 1: ERROR: MemoryError()
 in resize! at ./array.jl:504
 in sizehint at ./intset.jl:23
 in push! at ./intset.jl:42
 in call at deprecated.jl:115
 in runtests at /home/vagrant/src/julia/test/testdefs.jl:5
 in anonymous at multi.jl:632
 in run_work_thunk at multi.jl:593
 in remotecall_fetch at multi.jl:666
 in remotecall_fetch at multi.jl:681
 in anonymous at task.jl:1450
while loading collections.jl, in expression starting on line 520
ERROR: MemoryError()
 in resize! at ./array.jl:504
 in sizehint at ./intset.jl:23
 in push! at ./intset.jl:42
 in call at deprecated.jl:115
 in runtests at /home/vagrant/src/julia/test/testdefs.jl:5
 in anonymous at multi.jl:632
 in run_work_thunk at multi.jl:593
 in remotecall_fetch at multi.jl:666
 in remotecall_fetch at multi.jl:681
 in anonymous at task.jl:1450
while loading collections.jl, in expression starting on line 520
while loading /home/vagrant/src/julia/test/runtests.jl, in expression starting on line 42

make[1]: *** [collections] Error 1
make: *** [test-collections] Error 2

but I can at least comment that one out.

[simonbyrne]

I don't know why that worked, all I did was rebase. But it seems good to go.

[tkelman]

Looks like you did fix the original problem in decompose, the other issue is an intermittent thing that I don't think you caused, sorry if that was unclear. I have #9176 open since there are several intermittent failures happening on Linux Travis lately.

[simonbyrne]

I've just added an extra patch that should also fix FloatingPoint vs MathConst and Rational vs MathConst. So now all comparisons should be exact, except for some edge cases in BigFloat vs MathConst and Rational{BigInt} vs MathConst.

[simonbyrne]

Bump?