Empty ObjGroups are confusing to debug

[lundmark]

Hi,

I'm running tundra 2.0 beta11 and when trying to build my project I get the following error: [E] duplicate node guids: ObjGroup and ObjGroup share common GUID (bbdac33add54cc51f562e674fdb744d3)

Now I assume that this is because somehow two different ObjGroup's somehow generate the same GUID. I'm not really sure what it is that I've been doing wrong - this didn't come up from adding another objgroup or similar. It would be very nice if the names of those objgroups would be printed so that I could get some more information about the issue and how I could resolve it myself.

[lundmark]

So this was because I had two objgroups that had nothing in them, so it turns out that their GUID becomes the same. Much obliged if there was a warning or similar for empty objgroups.

[deplinenoise]

Thanks for the report. The GUID hashing is pretty lame, it simply uses the label of the node (the thing that prints when it executes) - it could probably be redesigned to use the input data in some more elaborate way.

[questor]

I'm not sure if I have the same issue, I have written a defrule for flatbuffers which generates from an idl an header file only (no implementation file) and writing that in a sources-statement triggers the "same guid" error. any ideas how to work around that limitation?

[questor]

to give you a bit more context:

DefRule {
   Name = "FbsCompiler",
   Pass = "CodeGeneration",
   Command = "flatc -c -b --scoped-enums $(<)",
   ImplicitInputs = {"flatc"},
   Blueprint = {
      FbsFile = { Required = true, Type = "string", Help = "Input filename" },
   },
   Setup = function(env, data)
      io.write(string.format("Test\n"))
      return {
            InputFiles = { data.FbsFile },
            OutputFiles = { 
               "$(OBJECTDIR)/"..string.gsub(data.FbsFile, ".fbs", "_generated.h"),
            },
         }
   end,
}

Program {
    Name = "test",
    Sources = {
      FbsCompiler { FbsFile = "monster.fbs" },
...

and in my case it seems the "ImplicitInputs" triggered the error. replacing that with "$(OBJECTDIR)$(SEP)flatc$(PROGSUFFIX)" fixed it for me...

[deplinenoise]

It seems DefRule uses the input files ($(<)) as the default label/annotation, which is then what is hashes to make a guid. You can supply your own annotation.

From the DefRule function:

  local annot     = ruledef.Annotation

  if not annot then
    annot = name .. " $(<)"
  end

So if you add Annotation = "FbsCompiler $(@)" then it should be unique because your output files have to be unique anyway.

[deplinenoise]

Closing as fixed. Let me know if it should be reopened.