Fix PyDict REPL completion without GIL

src/Core/Py.jl

@@ -125,10 +125,25 @@ Py(x::Date) = pydate(x)
 Py(x::Time) = pytime(x)
 Py(x::DateTime) = pydatetime(x)
 
+function _py_on_main_thread_if_needed(f)
+    if C.PyGILState_Check() == 1
+        f()
+    else
+        C.on_main_thread(f)
+    end
+end
+
 Base.string(x::Py) = pyisnull(x) ? "<py NULL>" : pystr(String, x)
 Base.print(io::IO, x::Py) = print(io, string(x))
 
 function Base.show(io::IO, x::Py)
+    _py_on_main_thread_if_needed() do
+        _show(io, x)
+        nothing
+    end
+end
+
+function _show(io::IO, x::Py)
     if get(io, :typeinfo, Any) == Py
         if pyisnull(x)
             print(io, "NULL")
@@ -292,13 +307,9 @@ function _propertynames(x::Py, private::Bool)
 end
 
 function Base.propertynames(x::Py, private::Bool = false)
-    if C.PyGILState_Check() == 1
+    _py_on_main_thread_if_needed() do
         _propertynames(x, private)
-    else
-        C.on_main_thread() do
-            _propertynames(x, private)
-        end::Vector{Symbol}
-    end
+    end::Vector{Symbol}
 end
 
 Base.Bool(x::Py) = pytruth(x)

src/Wrap/PyDict.jl

@@ -24,7 +24,19 @@ function Base.iterate(x::PyDict{K,V}, it::Py = pyiter(x)) where {K,V}
     return (k => v, it)
 end
 
-function Base.iterate(x::Base.KeySet{K,PyDict{K,V}}, it::Py = pyiter(x.dict)) where {K,V}
+function Base.iterate(x::Base.KeySet{K,<:PyDict{K}})::Union{Nothing,Tuple{K,Py}} where {K}
+    _py_on_main_thread_if_needed() do
+        _iterate(x, pyiter(x.dict))
+    end
+end
+
+function Base.iterate(x::Base.KeySet{K,<:PyDict{K}}, it::Py)::Union{Nothing,Tuple{K,Py}} where {K}
+    _py_on_main_thread_if_needed() do
+        _iterate(x, it)
+    end
+end
+
+function _iterate(x::Base.KeySet{K,<:PyDict{K}}, it::Py) where {K}
     k_ = unsafe_pynext(it)
     pyisnull(k_) && return nothing
     k = pyconvert(K, k_)

src/Wrap/Wrap.jl

@@ -20,7 +20,7 @@ using Base: @propagate_inbounds
 using Tables: Tables
 using UnsafePointers: UnsafePtr
 
-import ..Core: Py, ispy
+import ..Core: Py, ispy, _py_on_main_thread_if_needed
 
 include("PyIterable.jl")
 include("PyDict.jl")

test/Project.toml

@@ -5,6 +5,7 @@ Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
 PyCall = "438e738f-606a-5dbb-bf0a-cddfbfd45ab0"
 PythonCall = "6099a3de-0909-46bc-b1f4-468b9a2dfc0d"
+REPL = "3fa0cd96-eef1-5676-8a61-b3b8758bbffb"
 Serialization = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
 Tables = "bd369af6-aec1-5ad0-b16a-f7cc5008161c"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

test/Wrap.jl

@@ -122,6 +122,16 @@ end
     @testset "iterate keys" begin
         @test collect(keys(z)) == ["foo"]
     end
+    @testset "complete keys from another thread" begin
+        using REPL
+        task = Threads.@spawn begin
+            completions, _, _ = REPL.REPLCompletions.completions("y[", 2, @__MODULE__)
+            length(completions)
+        end
+        wait(task)
+        completion_count = fetch(task)
+        @test completion_count == 1
+    end
     @testset "getindex" begin
         @test z["foo"] === 12
         @test_throws KeyError z["bar"]