directive: customization takes if-set

Renamed `defined` to `if-set`.

doc/directives.md

@@ -169,17 +169,19 @@ otk.meta.kiwi:
 Customizations are conditional blocks that receive separate input through
 `otk compile -Cname=data`, a customization is considered to be active when it
 is passed data. If a customization is passed multiple times then the `defined`
-block is replaced multiple times, once for each data input.
+block is repeated multiple times, once for each input.
 
-Expects a `map` for its value which contains a `defined` key. The `default` key
-is optional. The values of `default` and `defined` can be of any type.
+Expects a `map` for its value which contains an `if-set` key. The `default` key
+is optional. If a `default` key is not passed and the customization is inactive
+then the customization block is effectively a no-op and will be removed from the
+tree. The values of `default` and `if-set` can be of any type.
 
 ```yaml
 otk.customization.name:
  default:
  - type: org.osbuild.stage
  options: none
- defined:
+ if-set:
  - type: org.osbuild.stage
  options: ${this.data} # it's not going to be `this`
  - type: org.osbuild.stage

src/otk/transform/directive.py

@@ -118,13 +118,14 @@ def op_map_merge(ctx: Context, tree: dict[str, Any]) -> Any:
 
 
 @tree.must_be(dict)
-@tree.must_pass(tree.has_keys(["default", "scope", "defined"]))
+@tree.must_pass(tree.has_keys(["scope", "if-set"]))
 def customization(ctx: Context, tree: dict[str, Any], key) -> Any:
  """Apply a customization."""
  log.warning("applying customization %r", key)
 
- # TODO take in customizations somewhere and use there here
- return tree["default"]
+ # TODO take in customizations somewhere and use them here, this is
+ # TODO currently just a placeholder.
+ return tree.get("default")
 
 
 @tree.must_be(str)

test/test_sugar.py

@@ -20,7 +20,7 @@ def test_simple_sugar():
 
  omnifest_result = resolve(context, omnifest_under_test)
 
- assert omnifest_result['my_var'] == "foo"
+ assert omnifest_result["my_var"] == "foo"
 
 
 def test_simple_sugar_tree():
@@ -39,7 +39,7 @@ def test_simple_sugar_tree():
 
  omnifest_result = resolve(context, omnifest_under_test)
 
- assert omnifest_result['my_var'] == [1, 2]
+ assert omnifest_result["my_var"] == [1, 2]
 
 
 def test_simple_sugar_tree_fail():
@@ -52,7 +52,7 @@ def test_simple_sugar_tree_fail():
 
 my_var: my_prefix_${variable}
 """
- expected_error = 'string sugar resolves to an incorrect type, expected int, float, or str but got %r'
+ expected_error = "string sugar resolves to an incorrect type, expected int, float, or str but got %r"
 
  context = Context()
  omnifest_under_test = Omnifest.from_yaml_bytes(data).to_tree()