dump: handle recursion better (#27051)

where better means at least as well as `show_default`
JuliaLang · May 10, 2018 · ee4b18f · ee4b18f
1 parent 5fb465f
commit ee4b18f
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Showing 2 changed files with 48 additions and 23 deletions.
diff --git a/base/show.jl b/base/show.jl
@@ -1599,7 +1599,7 @@ function show(io::IO, tv::TypeVar)
     nothing
 end
 
-function dump(io::IO, x::SimpleVector, n::Int, indent)
+function dump(io::IOContext, x::SimpleVector, n::Int, indent)
     if isempty(x)
         print(io, "empty SimpleVector")
         return
@@ -1619,37 +1619,40 @@ function dump(io::IO, x::SimpleVector, n::Int, indent)
     nothing
 end
 
-function dump(io::IO, @nospecialize(x), n::Int, indent)
+function dump(io::IOContext, @nospecialize(x), n::Int, indent)
     T = typeof(x)
     if isa(x, Function)
         print(io, x, " (function of type ", T, ")")
     else
         print(io, T)
     end
-    if nfields(x) > 0
-        if n > 0
-            for field in (isa(x,Tuple) ? (1:length(x)) : fieldnames(T))
+    nf = nfields(x)
+    if nf > 0
+        if n > 0 && !show_circular(io, x)
+            recur_io = IOContext(io, Pair{Symbol,Any}(:SHOWN_SET, x))
+            for field in 1:nf
                 println(io)
-                print(io, indent, "  ", field, ": ")
+                fname = string(fieldname(T, field))
+                print(io, indent, "  ", fname, ": ")
                 if isdefined(x,field)
-                    dump(io, getfield(x, field), n - 1, string(indent, "  "))
+                    dump(recur_io, getfield(x, field), n - 1, string(indent, "  "))
                 else
                     print(io, undef_ref_str)
                 end
             end
         end
     else
-        !isa(x,Function) && print(io, " ", x)
+        !isa(x, Function) && print(io, " ", x)
     end
     nothing
 end
 
-dump(io::IO, x::Module, n::Int, indent) = print(io, "Module ", x)
-dump(io::IO, x::String, n::Int, indent) = (print(io, "String "); show(io, x))
-dump(io::IO, x::Symbol, n::Int, indent) = print(io, typeof(x), " ", x)
-dump(io::IO, x::Union,  n::Int, indent) = print(io, x)
+dump(io::IOContext, x::Module, n::Int, indent) = print(io, "Module ", x)
+dump(io::IOContext, x::String, n::Int, indent) = (print(io, "String "); show(io, x))
+dump(io::IOContext, x::Symbol, n::Int, indent) = print(io, typeof(x), " ", x)
+dump(io::IOContext, x::Union,  n::Int, indent) = print(io, x)
 
-function dump_elts(io::IO, x::Array, n::Int, indent, i0, i1)
+function dump_elts(io::IOContext, x::Array, n::Int, indent, i0, i1)
     for i in i0:i1
         print(io, indent, "  ", i, ": ")
         if !isassigned(x,i)
@@ -1661,31 +1664,33 @@ function dump_elts(io::IO, x::Array, n::Int, indent, i0, i1)
     end
 end
 
-function dump(io::IO, x::Array, n::Int, indent)
+function dump(io::IOContext, x::Array, n::Int, indent)
     print(io, "Array{$(eltype(x))}($(size(x)))")
     if eltype(x) <: Number
         print(io, " ")
         show(io, x)
     else
-        if n > 0 && !isempty(x)
+        if n > 0 && !isempty(x) && !show_circular(io, x)
             println(io)
+            recur_io = IOContext(io, :SHOWN_SET => x)
+            lx = length(x)
             if get(io, :limit, false)
-                dump_elts(io, x, n, indent, 1, (length(x) <= 10 ? length(x) : 5))
-                if length(x) > 10
+                dump_elts(recur_io, x, n, indent, 1, (lx <= 10 ? lx : 5))
+                if lx > 10
                     println(io)
                     println(io, indent, "  ...")
-                    dump_elts(io, x, n, indent, length(x)-4, length(x))
+                    dump_elts(recur_io, x, n, indent, lx - 4, lx)
                 end
             else
-                dump_elts(io, x, n, indent, 1, length(x))
+                dump_elts(recur_io, x, n, indent, 1, lx)
             end
         end
     end
     nothing
 end
 
 # Types
-function dump(io::IO, x::DataType, n::Int, indent)
+function dump(io::IOContext, x::DataType, n::Int, indent)
     print(io, x)
     if x !== Any
         print(io, " <: ", supertype(x))
@@ -1712,7 +1717,10 @@ end
 
 const DUMP_DEFAULT_MAXDEPTH = 8
 
-dump(io::IO, arg; maxdepth=DUMP_DEFAULT_MAXDEPTH) = (dump(io, arg, maxdepth, ""); println(io))
+function dump(io::IO, @nospecialize(x); maxdepth=DUMP_DEFAULT_MAXDEPTH)
+    dump(IOContext(io), x, maxdepth, "")
+    println(io)
+end
 
 """
     dump(x; maxdepth=$DUMP_DEFAULT_MAXDEPTH)

diff --git a/test/show.jl b/test/show.jl
@@ -726,10 +726,27 @@ test_mt(show_f5, "show_f5(A::AbstractArray{T,N}, indices::Vararg{$Int,N})")
 @test_repr "continue"
 @test_repr "break"
 
-let x = [], y = []
+let x = [], y = [], z = Base.ImmutableDict(x => y)
     push!(x, y)
     push!(y, x)
-    @test replstr(x) == "1-element Array{Any,1}:\n Any[Any[Any[#= circular reference @-2 =#]]]"
+    push!(y, z)
+    @test replstr(x) == "1-element Array{Any,1}:\n Any[Any[Any[#= circular reference @-2 =#]], Base.ImmutableDict(Any[Any[#= circular reference @-3 =#]]=>Any[#= circular reference @-2 =#])]"
+    @test repr(z) == "Base.ImmutableDict(Any[Any[Any[#= circular reference @-2 =#], Base.ImmutableDict(#= circular reference @-3 =#)]]=>Any[Any[Any[#= circular reference @-2 =#]], Base.ImmutableDict(#= circular reference @-2 =#)])"
+    @test sprint(dump, x) == """
+        Array{Any}((1,))
+          1: Array{Any}((2,))
+            1: Array{Any}((1,))#= circular reference @-2 =#
+            2: Base.ImmutableDict{Array{Any,1},Array{Any,1}}
+              parent: Base.ImmutableDict{Array{Any,1},Array{Any,1}}
+                parent: #undef
+                key: #undef
+                value: #undef
+              key: Array{Any}((1,))#= circular reference @-3 =#
+              value: Array{Any}((2,))#= circular reference @-2 =#
+        """
+    dz = sprint(dump, z)
+    @test 10 < countlines(IOBuffer(dz)) < 40
+    @test sum(x -> 1, eachmatch(r"circular reference", dz)) == 4
 end
 
 # PR 16221