Move JLD2.jl dependency to a package extension

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
           - version: '1'
             os: ubuntu-latest
             arch: x64
-          - version: '1.5'
+          - version: '1.10'
             os: ubuntu-latest
             arch: x64
           - version: 'nightly'

Project.toml

@@ -1,20 +1,26 @@
 name = "MetaGraphs"
 uuid = "626554b9-1ddb-594c-aa3c-2596fe9399a5"
-version = "0.8.1"
+version = "0.9.0"
 
 [deps]
 Graphs = "86223c79-3864-5bf0-83f7-82e725a168b6"
-JLD2 = "033835bb-8acc-5ee8-8aae-3f567f8a3819"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
+[weakdeps]
+JLD2 = "033835bb-8acc-5ee8-8aae-3f567f8a3819"
+
+[extensions]
+MetaGraphsJLD2Ext = ["Graphs", "JLD2"]
+
 [compat]
 Graphs = "1.4"
 JLD2 = "0.1.11, 0.2, 0.3, 0.4, 0.5, 0.6"
-julia = "1"
+julia = "1.10"
 
 [extras]
 Base64 = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
+JLD2 = "033835bb-8acc-5ee8-8aae-3f567f8a3819"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
 
 [targets]
-test = ["Test", "Base64"]
+test = ["Test", "Base64", "JLD2"]

ext/MetaGraphsJLD2Ext.jl

@@ -0,0 +1,74 @@
+module MetaGraphsJLD2Ext
+
+using Graphs
+using JLD2
+using MetaGraphs
+
+function MetaGraphs.loadmg(fn::AbstractString)
+    @load fn g
+    return g
+end
+
+function MetaGraphs.savemg(fn::AbstractString, g::AbstractMetaGraph)
+    @save fn g
+    return 1
+end
+
+# escaping unescaped quotation marks
+# i.e. replacing `"`` with `\"` while leaving `\"` as is
+escape_quotes(s::AbstractString) = replace(s, r"([^\\])\"" => s"\1\\\\\"")
+
+# According to the DOT language specification https://graphviz.org/doc/info/lang.html
+# we can quote everyhthing that's not an XML/HTML literal
+function quote_prop(p::AbstractString)
+    if  occursin(r"<+.*>+$", p)
+        # The label is an HTML string, no additional quotes here.
+        return p
+    else
+        return "\"" * escape_quotes(p) * "\""
+    end
+end
+# if the property value is _not_ a string it cannot be XML/HTML literal, so just put it in quotes
+quote_prop(p::Any) = "\"" * escape_quotes(string(p)) * "\""
+# NOTE: down there I only quote property _values_. DOT allows quoting property _names_ too
+# I don't do that as long as names are Symbols and can't have spaces and commas and stuff.
+# That will break if someone uses a DOT keyword as a property name, as they must be quoted.
+
+function MetaGraphs.savedot(io::IO, g::AbstractMetaGraph)
+    if is_directed(g)
+        write(io, "digraph G {\n")
+        dash = "->"
+    else
+        write(io, "graph G {\n")
+        dash = "--"
+    end
+
+    for p in props(g)
+        write(io, "$(p[1])=$(quote_prop(p[2]));\n")
+    end
+
+    for v in vertices(g)
+        write(io, "$v")
+        if length(props(g, v)) > 0
+            write(io, " [ ")
+
+            for p in props(g, v)
+                write(io, "$(p[1])=$(quote_prop(p[2])), ")
+            end
+
+            write(io, "];")
+        end
+        write(io, "\n")
+    end
+
+    for e in edges(g)
+        write(io, "$(src(e)) $dash $(dst(e)) [ ")
+        for p in props(g,e)
+            write(io, "$(p[1])=$(quote_prop(p[2])), ")
+        end
+        write(io, "]\n")
+    end
+    write(io, "}\n")
+end
+
+end

src/MetaGraphs.jl

@@ -1,6 +1,5 @@
 module MetaGraphs
 using Graphs
-using JLD2
 
 import Base:
     eltype, show, ==, Pair,
@@ -582,4 +581,20 @@ include("metadigraph.jl")
 include("metagraph.jl")
 include("persistence.jl")
 include("overrides.jl")
+
+function __init__()
+    # Register error hint for the `loadmg`, `savemg`, and `savedot` functions
+    if isdefined(Base.Experimental, :register_error_hint)
+        Base.Experimental.register_error_hint(MethodError) do io, exc, _, _
+            if exc.f === loadsg
+                print(io, "\n\nIn order to load meta graphs from binary files, you need \
+                to load the JLD2.jl package.")
+            elseif exc.f === savesg
+                print(io,"\n\nIn order to save meta graphs to binary files, you need to \
+                load the JLD2.jl package.")
+            end
+        end
+    end
+end
+
 end # module

src/persistence.jl

@@ -3,76 +3,12 @@
 struct MGFormat <: AbstractGraphFormat end
 struct DOTFormat <: AbstractGraphFormat end
 
-function loadmg(fn::AbstractString)
-    @load fn g
-    return g
-end
-
-function savemg(fn::AbstractString, g::AbstractMetaGraph)
-    @save fn g
-    return 1
-end
-
-loadgraph(fn::AbstractString, gname::String, ::MGFormat) = loadmg(fn)
-savegraph(fn::AbstractString, g::AbstractMetaGraph) =  savemg(fn, g)
-
-# escaping unescaped quotation marks
-# i.e. replacing `"`` with `\"` while leaving `\"` as is
-escape_quotes(s::AbstractString) = replace(s, r"([^\\])\"" => s"\1\\\\\"")
+function loadmg end
+function savemg end
+function savedot end
 
-# According to the DOT language specification https://graphviz.org/doc/info/lang.html
-# we can quote everyhthing that's not an XML/HTML literal
-function quote_prop(p::AbstractString)
-    if  occursin(r"<+.*>+$", p)
-        # The label is an HTML string, no additional quotes here.
-        return p
-    else
-        return "\"" * escape_quotes(p) * "\""
-    end
-end
-# if the property value is _not_ a string it cannot be XML/HTML literal, so just put it in quotes
-quote_prop(p::Any) = "\"" * escape_quotes(string(p)) * "\""
-# NOTE: down there I only quote property _values_. DOT allows quoting property _names_ too
-# I don't do that as long as names are Symbols and can't have spaces and commas and stuff.
-# That will break if someone uses a DOT keyword as a property name, as they must be quoted.
-
-function savedot(io::IO, g::AbstractMetaGraph)
-
-    if is_directed(g)
-        write(io, "digraph G {\n")
-        dash = "->"
-    else
-        write(io, "graph G {\n")
-        dash = "--"
-    end
-
-    for p in props(g)
-        write(io, "$(p[1])=$(quote_prop(p[2]));\n")
-    end
-
-    for v in vertices(g)
-        write(io, "$v")
-        if length(props(g, v)) > 0
-            write(io, " [ ")
-
-            for p in props(g, v)
-                write(io, "$(p[1])=$(quote_prop(p[2])), ")
-            end
-
-            write(io, "];")
-        end
-        write(io, "\n")
-    end
-
-    for e in edges(g)
-        write(io, "$(src(e)) $dash $(dst(e)) [ ")
-        for p in props(g,e)
-            write(io, "$(p[1])=$(quote_prop(p[2])), ")
-        end
-        write(io, "]\n")
-    end
-    write(io, "}\n")
-end
+loadgraph(fn::AbstractString, ::String, ::MGFormat) = loadmg(fn)
+savegraph(fn::AbstractString, g::AbstractMetaGraph) = savemg(fn, g)
 
 function savegraph(fn::AbstractString, g::AbstractMetaGraph, ::DOTFormat)
     open(fn, "w") do fp

test/runtests.jl

@@ -1,5 +1,7 @@
 using Graphs
 using MetaGraphs
+
+using JLD2
 using Test
 
 import Graphs.SimpleGraphs: SimpleGraph, SimpleDiGraph