To be honest, I don't think this will fix #298. It's the nil ctx that cause the panic, which means like

var ctx *martian.Context
i, ok := ctx.Get("key")  // panic here
fmt.Print(i, ok)

@zema1 is correct and the line of code is WAI, even if it looks a little weird. You're right that Get returns a value and an ok, but the value that we put in the context on line 60 is an error.

+1 to what @zema1 and @admtnnr said. The line martian.NewContext(res.Request) seems to return a null pointer in line 77. Somehow the stored Context* value in ctxs map is null for this request.