fix: check key values, not get return for haskey(k, orderedrobindict) (#858)

* fix: check key values, not `get` return for haskey(k, orderedrobindict)

* Fix: use isequal in setindex!

* re-fix: use `get` for `in keys()` but descend to the actual id-dict

* Remove accidental paste in docstring

* consolidate tests for issue under testset

---------

Co-authored-by: Micah Rufsvold <mjrufsvold@mathematica-mpr.com>

Author: mrufsvold

src/ordered_robin_dict.jl

@@ -132,7 +132,7 @@ function Base.setindex!(h::OrderedRobinDict{K, V}, v0, key0) where {K,V}
     else
         @assert haskey(h, key0)
         @inbounds orig_v = h.vals[index]
-        (orig_v != v0) && (@inbounds h.vals[index] = v0)
+        !isequal(orig_v, v0) && (@inbounds h.vals[index] = v0)
     end
 
     check_for_rehash(h) && rehash!(h)
@@ -305,8 +305,8 @@ julia> haskey(D, 'c')
 false
 ```
 """
-Base.haskey(h::OrderedRobinDict, key) = (get(h.dict, key, -2) > 0)
-Base.in(key, v::Base.KeySet{K,T}) where {K,T<:OrderedRobinDict{K}} = (get(v.dict, key, -1) >= 0)
+Base.haskey(h::OrderedRobinDict, key) = (get(h.dict, key, -1) > 0)
+Base.in(key, v::Base.KeySet{K,T}) where {K,T<:OrderedRobinDict{K}} = (get(v.dict.dict, key, -1) >= 0)
 
 """
     getkey(collection, key, default)

test/runtests.jl

@@ -8,7 +8,8 @@ import DataStructures: IntSet
 @test [] == detect_ambiguities(Core, DataStructures)
 @test [] == detect_ambiguities(Base, DataStructures)
 
-tests = ["deprecations",
+tests = [
+         "deprecations",
          "int_set",
          "sparse_int_set",
          "deque",

test/test_ordered_robin_dict.jl

@@ -78,6 +78,13 @@
         @test od60[14] == 15
     end
 
+    @testset "Fixes issue 857" begin
+        h = OrderedRobinDict{Any,Any}([("a", missing), ("b", -2)])
+        @test 5 == (h["a"] = 5)
+        @test "b" in keys(h)
+        @test haskey(h,"b")
+    end
+
 
     # #############################
     # Copied and modified from Base/test/dict.jl