Safe figure saving by default, + new arg

PlotsBase/src/Commons/attrs.jl

@@ -410,6 +410,7 @@ const _plot_defaults = KW(
     :thickness_scaling   => 1,
     :display_type        => :auto,
     :warn_on_unsupported => true,
+    :safe_saving         => true,
     :extra_plot_kwargs   => Dict(),
     :extra_kwargs        => :series,    # directs collection of extra_kwargs
 )

PlotsBase/src/arg_desc.jl

@@ -83,6 +83,7 @@ const _arg_desc = KW(
                                  Example: `pgfplotsx(); scatter(1:5, extra_kwargs=Dict(:subplot=>Dict("axis line shift" => "10pt"))`."""),
     :fontfamily               => (Union{AStr,Symbol}, "Default font family for title, legend entries, tick labels and guides."),
     :warn_on_unsupported      => (Bool, "Warn on unsupported attributes, series types and marker shapes."),
+    :safe_saving              => (Bool, "Do not override existing files when saving to disk. Choose from (true, false), i.e. `plot(rand(10), safe_saving=false)` for enable file overriding"),
 
     # subplot args
     :title                       => (AStr, "Subplot title."),

PlotsBase/src/output.jl

@@ -138,7 +138,10 @@ file types, some also support svg, ps, eps, html and tex.
 """
 function savefig(plt::Plot, fn) # fn might be an `AbstractString` or an `AbstractPath` from `FilePaths.jl`
     fn = abspath(expanduser(fn))
-
+    if isfile(fn) && plt[:safe_saving]
+        @warn "Filename $fn already exists, defaulting to prevent overriding. To disable this behavior, provide `:safe_saving=false` kwarg, i.e. `plot(rand(10), safe_saving=false)`"
+        return
+    end
     # get the extension
     _, ext = splitext(fn)
     ext = chop(ext, head = 1, tail = 0)