Julia: Mistaken inference error on first call
Distilled from ImageMagick.jl:
mapIM(x::Number) = x
function breaks(img, mapi=identity)
local imgw
try
imgw = map(x->mapIM(mapi(x)), img)
catch
warn("this type didn't work")
rethrow()
end
end
mutable struct TestType end
breaks([TestType() TestType()])
Upon usage:
julia> include("/home/tim/tmp/im_bug.jl")
WARNING: this type didn't work
ERROR: LoadError: TypeError: Dense: in T, expected T<:Union{Complex{Float64}, Float64}, got Type{StackFrame}
Stacktrace:
[1] _methods_by_ftype(::Any, ::Int64, ::UInt64, ::Array{UInt64,1}, ::Array{UInt64,1}) at ./reflection.jl:521
[2] abstract_call_gf_by_type(::Any, ::Any, ::Core.Inference.InferenceState) at ./inference.jl:1267
[3] abstract_call(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1864
[4] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1894
[5] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[6] copy!(::Array{Any,1}, ::Core.Inference.Generator{Array{Any,1},Core.Inference.##187#188{Array{Any,1},Core.Inference.InferenceState}}) at ./abstractarray.jl:565
[7] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1868
[8] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[9] abstract_interpret(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:2040
[10] typeinf_frame(::Core.Inference.InferenceState) at ./inference.jl:2704
[11] typeinf_loop(::Core.Inference.InferenceState) at ./inference.jl:2603
[12] typeinf_frame(::Core.MethodInstance, ::Core.Inference.InferenceState, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2473
[13] typeinf_edge(::Method, ::Any, ::SimpleVector, ::Core.Inference.InferenceState) at ./inference.jl:2496
[14] abstract_call_gf_by_type(::Any, ::Any, ::Core.Inference.InferenceState) at ./inference.jl:1386
[15] abstract_call(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1864
[16] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1894
[17] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[18] typeinf_frame(::Core.Inference.InferenceState) at ./inference.jl:2757
[19] typeinf_loop(::Core.Inference.InferenceState) at ./inference.jl:2603
[20] typeinf_frame(::Core.MethodInstance, ::Core.Inference.InferenceState, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2473
[21] typeinf_edge(::Method, ::Any, ::SimpleVector, ::Core.Inference.InferenceState) at ./inference.jl:2496
[22] abstract_call_gf_by_type(::Any, ::Any, ::Core.Inference.InferenceState) at ./inference.jl:1386
[23] abstract_call(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1864
[24] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1894
[25] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[26] abstract_interpret(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:2040
[27] typeinf_frame(::Core.Inference.InferenceState) at ./inference.jl:2704
[28] typeinf_loop(::Core.Inference.InferenceState) at ./inference.jl:2603
[29] typeinf_frame(::Core.MethodInstance, ::Core.Inference.InferenceState, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2473
[30] typeinf_edge(::Method, ::Any, ::SimpleVector, ::Core.Inference.InferenceState) at ./inference.jl:2496
[31] abstract_call_gf_by_type(::Any, ::Any, ::Core.Inference.InferenceState) at ./inference.jl:1386
[32] abstract_call(::Any, ::Tuple{}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1864
[33] abstract_apply(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1516
[34] abstract_call(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1648
[35] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1894
[36] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[37] typeinf_frame(::Core.Inference.InferenceState) at ./inference.jl:2757
[38] typeinf_loop(::Core.Inference.InferenceState) at ./inference.jl:2620
[39] typeinf_frame(::Core.MethodInstance, ::Void, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2473
[40] typeinf_code(::Core.MethodInstance, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2543
[41] typeinf_ext(::Core.MethodInstance, ::UInt64) at ./inference.jl:2582
[42] #warn#515(::Array{Any,1}, ::Function, ::String, ::Vararg{String,N} where N) at ./util.jl:585
[43] breaks(::Array{TestType,2}, ::Base.#identity) at /home/tim/tmp/im_bug.jl:8
[44] breaks(::Array{TestType,2}) at /home/tim/tmp/im_bug.jl:4
[45] include_from_node1(::String) at ./loading.jl:539
[46] include(::String) at ./sysimg.jl:14
while loading /home/tim/tmp/im_bug.jl, in expression starting on line 15
julia> breaks([TestType() TestType()])
WARNING: this type didn't work
ERROR: MethodError: no method matching mapIM(::TestType)
Closest candidates are:
mapIM(::Number) at /home/tim/tmp/im_bug.jl:1
Stacktrace:
[1] _collect(::Array{TestType,2}, ::Base.Generator{Array{TestType,2},##3#4{Base.#identity}}, ::Base.EltypeUnknown, ::Base.HasShape) at ./array.jl:441
[2] breaks(::Array{TestType,2}, ::Base.#identity) at /home/tim/tmp/im_bug.jl:6
[3] breaks(::Array{TestType,2}) at /home/tim/tmp/im_bug.jl:4
timholy
All 4 comments
Even simpler repro:
julia> function breaks()
try
error("ohoh")
catch
warn(STDERR, "this didn't work")
rethrow()
end
end
breaks (generic function with 1 method)
julia> breaks()
WARNING: this didn't work
ERROR: TypeError: Dense: in T, expected T<:Union{Complex{Float64}, Float64}, got Type{StackFrame}
Stacktrace:
[1] _methods_by_ftype(::Any, ::Int64, ::UInt64, ::Array{UInt64,1}, ::Array{UInt64,1}) at ./reflection.jl:521
[2] abstract_call_gf_by_type(::Any, ::Any, ::Core.Inference.InferenceState) at ./inference.jl:1267
[3] abstract_call(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1864
[4] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1894
[5] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[6] copy!(::Array{Any,1}, ::Core.Inference.Generator{Array{Any,1},Core.Inference.##187#188{Array{Any,1},Core.Inference.InferenceState}}) at ./abstractarray.jl:565
[7] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1868
[8] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[9] abstract_interpret(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:2040
[10] typeinf_frame(::Core.Inference.InferenceState) at ./inference.jl:2704
[11] typeinf_loop(::Core.Inference.InferenceState) at ./inference.jl:2603
[12] typeinf_frame(::Core.MethodInstance, ::Core.Inference.InferenceState, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2473
[13] typeinf_edge(::Method, ::Any, ::SimpleVector, ::Core.Inference.InferenceState) at ./inference.jl:2496
[14] abstract_call_gf_by_type(::Any, ::Any, ::Core.Inference.InferenceState) at ./inference.jl:1386
[15] abstract_call(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1864
[16] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1894
[17] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[18] typeinf_frame(::Core.Inference.InferenceState) at ./inference.jl:2757
[19] typeinf_loop(::Core.Inference.InferenceState) at ./inference.jl:2603
[20] typeinf_frame(::Core.MethodInstance, ::Core.Inference.InferenceState, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2473
[21] typeinf_edge(::Method, ::Any, ::SimpleVector, ::Core.Inference.InferenceState) at ./inference.jl:2496
[22] abstract_call_gf_by_type(::Any, ::Any, ::Core.Inference.InferenceState) at ./inference.jl:1386
[23] abstract_call(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1864
[24] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1894
[25] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[26] abstract_interpret(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:2040
[27] typeinf_frame(::Core.Inference.InferenceState) at ./inference.jl:2704
[28] typeinf_loop(::Core.Inference.InferenceState) at ./inference.jl:2603
[29] typeinf_frame(::Core.MethodInstance, ::Core.Inference.InferenceState, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2473
[30] typeinf_edge(::Method, ::Any, ::SimpleVector, ::Core.Inference.InferenceState) at ./inference.jl:2496
[31] abstract_call_gf_by_type(::Any, ::Any, ::Core.Inference.InferenceState) at ./inference.jl:1386
[32] abstract_call(::Any, ::Tuple{}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1864
[33] abstract_apply(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1516
[34] abstract_call(::Any, ::Array{Any,1}, ::Array{Any,1}, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1648
[35] abstract_eval_call(::Expr, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1894
[36] abstract_eval(::Any, ::Array{Any,1}, ::Core.Inference.InferenceState) at ./inference.jl:1917
[37] typeinf_frame(::Core.Inference.InferenceState) at ./inference.jl:2757
[38] typeinf_loop(::Core.Inference.InferenceState) at ./inference.jl:2620
[39] typeinf_frame(::Core.MethodInstance, ::Void, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2473
[40] typeinf_code(::Core.MethodInstance, ::Bool, ::Bool, ::Core.Inference.InferenceParams) at ./inference.jl:2543
[41] typeinf_ext(::Core.MethodInstance, ::UInt64) at ./inference.jl:2582
[42] breaks() at ./REPL[1]:5
BUT (in a fresh session):
julia> function breaks()
try
error("ohoh")
catch
warn(STDERR, "this didn't work")
rethrow()
end
end
breaks (generic function with 1 method)
julia> warn(STDERR, "this didn't work")
WARNING: this didn't work
julia> breaks()
WARNING: this didn't work
ERROR: ohoh
Stacktrace:
[1] breaks() at ./REPL[0]:3
Also (fresh session again):
julia> warn(STDERR, "this didn't work")
WARNING: this didn't work
julia> rethrow()
ERROR: TypeError: Dense: in T, expected T<:Union{Complex{Float64}, Float64}, got Type{StackFrame}
So I guess this is #19979 and for some reason there is an exception thrown and caught inside the type inference of warn.
martinholters
on 13 Apr 2017
Yes, these internal exceptions are pretty annoying. Maybe finally time to tackle it.
What's happening is that we often need to try instantiating types, and only find out that the instantiation is invalid by catching the type error that's thrown. For example this case is intersecting:
Tuple{typeof(Base.convert), Type{Array{Base.StackTraces.StackFrame, 1}}, Any}
Tuple{typeof(Base.convert), Type{Array{T, 1}}, Base.SparseArrays.CHOLMOD.Dense{T}} where T
which overlap if, perversely, we have a CHOLMOD.Dense{StackFrame} (one of the funniest types I have seen, so that's a plus). We can only find this out by trying the full substitution of StackFrame for T in the second type.
JeffBezanson
on 14 Apr 2017
😄1
I think that's one facet of it. I think the solution here is that we should save/restore the error/backtrace across calls to compilation / type-inference in jl_type_infer,jl_compile_for_dispatch, and jl_run_finalizer so that the operation of those functions is transparent to the callee. Someday later, we can consider making the rethrow function require an explicit object so that it is inherently scoped, but that should be OK to be entirely separate.
vtjnash
on 14 Apr 2017
👍1
Yes, that would be good. Even easier, we could disable collection of backtraces in those contexts, which would save the compiler some time too.
JeffBezanson
on 14 Apr 2017
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