serialize pointers as NULL. fixes #13122

JuliaLang · Oct 26, 2015 · 77b2527 · 77b2527 · andreasnoack · Oct 26, 2015
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commit 77b2527
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Showing 3 changed files with 9 additions and 5 deletions.
diff --git a/base/docs/helpdb.jl b/base/docs/helpdb.jl
@@ -4160,7 +4160,11 @@ pipeline(command)
 doc"""
     serialize(stream, value)
 
-Write an arbitrary value to a stream in an opaque format, such that it can be read back by `deserialize`. The read-back value will be as identical as possible to the original. In general, this process will not work if the reading and writing are done by different versions of Julia, or an instance of Julia with a different system image.
+Write an arbitrary value to a stream in an opaque format, such that it can be read back by `deserialize`.
+The read-back value will be as identical as possible to the original.
+In general, this process will not work if the reading and writing are done by different versions of Julia,
+or an instance of Julia with a different system image.
+`Ptr` values are serialized as all-zero bit patterns (`NULL`).
 """
 serialize
 

diff --git a/base/serialize.jl b/base/serialize.jl
@@ -102,7 +102,7 @@ end
 serialize(s::SerializationState, x::Bool) = x ? writetag(s.io, TRUE_TAG) :
                                                 writetag(s.io, FALSE_TAG)
 
-serialize(s::SerializationState, ::Ptr) = error("cannot serialize a pointer")
+serialize(s::SerializationState, p::Ptr) = serialize_any(s, oftype(p, C_NULL))
 
 serialize(s::SerializationState, ::Tuple{}) = writetag(s.io, EMPTYTUPLE_TAG)
 
@@ -651,8 +651,6 @@ function deserialize_datatype(s::SerializationState)
     deserialize(s, t)
 end
 
-deserialize{T}(s::SerializationState, ::Type{Ptr{T}}) = convert(Ptr{T}, 0)
-
 function deserialize(s::SerializationState, ::Type{Task})
     t = Task(()->nothing)
     deserialize_cycle(s, t)

diff --git a/test/serialize.jl b/test/serialize.jl
@@ -39,7 +39,9 @@ end
 
 # Ptr
 create_serialization_stream() do s
-    @test_throws ErrorException serialize(s, C_NULL)
+    serialize(s, C_NULL)
+    seekstart(s)
+    @test deserialize(s) === C_NULL
 end
 
 # Integer