Random errors in method definitions

[johnmyleswhite]

From what I can see, Julia randomly fails to define some methods in DataFrames correctly. Below are two runs of the current DataFrames master branch test suite in sequence: the first fails and the second succeeds even though nothing has changed in the underlying code in between. This has been happening for a long time now, but the randomness has made it hard for me to pin down.

What seems to happen is that line 402 of dataarray.jl sometimes get defined correctly and other times winds up getting defined as if it returned nothing. Perhaps there's some race condition in the method definitions? I honestly have no idea how to make sense of this. I used to think it had something to do with the data sets we generated using an RNG, but that seems less likely now.

jmwmacbookpro:DataFrames johnmyleswhite$ julia run_tests.jl 
Running tests:
 * test/dataarray.jl
 * test/extras.jl
 * test/pooleddataarray.jl
 * test/data.jl
 * test/index.jl
 * test/dataframe.jl
 * test/operators.jl
 * test/io.jl
 * test/constructors.jl
 * test/abstractarray.jl
 * test/booleans.jl
 * test/indexing.jl
 * test/sort.jl
 * test/iteration.jl
 * test/colfuncs.jl
 * test/duplicates.jl
 * test/padding.jl
 * test/tabulation.jl
 * test/datamatrix.jl
ERROR: no method *(DataArray{Float64,1},Nothing)
 in include_from_node1 at loading.jl:91
 in anonymous at no file:35
 in include_from_node1 at loading.jl:91
 in process_options at client.jl:274
 in _start at client.jl:347
at /Users/johnmyleswhite/.julia/DataFrames/test/datamatrix.jl:45
at /Users/johnmyleswhite/.julia/DataFrames/run_tests.jl:36

jmwmacbookpro:DataFrames johnmyleswhite$ julia run_tests.jl 
Running tests:
 * test/dataarray.jl
 * test/extras.jl
 * test/pooleddataarray.jl
 * test/data.jl
 * test/index.jl
 * test/dataframe.jl
 * test/operators.jl
 * test/io.jl
 * test/constructors.jl
 * test/abstractarray.jl
 * test/booleans.jl
 * test/indexing.jl
 * test/sort.jl
 * test/iteration.jl
 * test/colfuncs.jl
 * test/duplicates.jl
 * test/padding.jl
 * test/tabulation.jl
 * test/datamatrix.jl

Sorry for raising such a strange issue.

[simonster]

@johnmyleswhite I tried to track down the cause of this failure a while back and filed #3400.

[johnmyleswhite]

Ah. Sorry for the double issue then.