addresses https://github.com/JuliaGraphs/GraphIO.jl/pull/18#issuecomm… (#1038)

* addresses JuliaGraphs/GraphIO.jl#18 (comment)

* test coverage

Author: sbromberger

src/persistence/common.jl

@@ -70,8 +70,13 @@ The default graph name assigned to `gname` may change in the future.
 function savegraph(fn::AbstractString, g::AbstractGraph, gname::AbstractString,
         format::AbstractGraphFormat; compress=nothing
     )
-    compress === nothing ||
-    Base.depwarn("Saving compressed graphs is no longer supported in LightGraphs. Use `LGCompressedFormat()` from the `GraphIO.jl` package instead. Saving uncompressed.", :savegraph)
+    if compress !== nothing
+        if !compress
+            @info("Note: the `compress` keyword is no longer supported in LightGraphs. Saving uncompressed.") 
+        else
+            Base.depwarn("Saving compressed graphs is no longer supported in LightGraphs. Use `LGCompressedFormat()` from the `GraphIO.jl` package instead. Saving uncompressed.", :savegraph)
+        end
+    end
     io = open(fn, "w")
     try
         return savegraph(io, g, gname, format)

test/persistence/persistence.jl

@@ -11,6 +11,7 @@
     @test_deprecated r"Saving compressed graphs is no longer supported" savegraph(f, p1; compress=true)
     @test savegraph(f, p1) == 1
     @test_deprecated r"Saving compressed graphs is no longer supported" savegraph(f, p1, LGFormat(); compress=true)
+    @test_logs (:info,r"Note: the `compress` keyword is no longer supported in LightGraphs") savegraph(f, p1; compress=false)
     @test savegraph(f, p1, LGFormat()) == 1
     @test savegraph(f, p2) == 1
     @test (ne(p2), nv(p2)) == (9, 10)