How to move GYP target to a separate include file - c++

Question

I want many gyp scripts to have a common target. So I decided to move it to a separate include file. Simplest test-case that produces an error:
foo.gyp
{
'includes' : [
'bar.gypi',
],
}
bar.gypi
{
'targets': [
{
'target_name' : 'phony',
'type' : 'none',
'actions' : [
{
'action_name' : '_phony_',
'inputs' : ['',],
'outputs' : ['',],
'action' : ['_phony_',],
'message' : '_phony_',
},
],
},
],
}
Produces error:
IndexError: string index out of range while reading includes of
foo.gyp while tr ying to load foo.gyp
Some observations:
If I delete actions from target, everything parses well
If I move targets (with actions) to foo.gyp, everything parses well
Am I doing something wrong?

Answer 1

It looks like the "outputs" list can not be empty or contain an empty string:
# gyp/make.py:893
self.WriteLn("%s: obj := $(abs_obj)" % QuoteSpaces(outputs[0]))
You may have empty inputs but in this case the phony action will shoot only once. I haven't found any mentions of phony actions in the GYP documentation, but I have the following variant working:
# bar.gypi
{
'targets': [
{
'target_name' : 'phony',
'type' : 'none',
'actions' : [
{
'action_name' : '_phony_',
'inputs' : ['./bar.gypi'], # The action depends on this file
'outputs' : ['test'], # Some dummy file
'action' : ['echo', 'test'],
'message' : 'Running phony target',
},
],
},
],
}
I could try to find a better way if you tell me more about the task you are trying to solve.