Merge branch 'danielsilverstone-ct/yaml-sentinel-rework' into 'master'

Move _sentinel from utils.py to _yaml.py

See merge request BuildStream/buildstream!903

4 files changed, 7 insertions, 18 deletions

diff --git a/buildstream/_yaml.py b/buildstream/_yaml.py
index 940ca81e5..ca12acae9 100644
--- a/buildstream/_yaml.py
+++ b/buildstream/_yaml.py
@@ -335,16 +335,9 @@ def node_get_provenance(node, key=None, indices=None):
     return provenance
 
 
-# Helper to use utils.sentinel without unconditional utils import,
-# which causes issues for completion.
-#
-# Local private, but defined here because sphinx appears to break if
-# it's not defined before any functions calling it in default kwarg
-# values.
-#
-def _get_sentinel():
-    from .utils import _sentinel
-    return _sentinel
+# A sentinel to be used as a default argument for functions that need
+# to distinguish between a kwarg set to None and an unset kwarg.
+_sentinel = object()
 
 
 # node_get()
@@ -368,10 +361,10 @@ def _get_sentinel():
 # Note:
 #    Returned strings are stripped of leading and trailing whitespace
 #
-def node_get(node, expected_type, key, indices=None, default_value=_get_sentinel()):
+def node_get(node, expected_type, key, indices=None, default_value=_sentinel):
     value = node.get(key, default_value)
     provenance = node_get_provenance(node)
-    if value is _get_sentinel():
+    if value is _sentinel:
         raise LoadError(LoadErrorReason.INVALID_DATA,
                         "{}: Dictionary did not contain expected key '{}'".format(provenance, key))
 
diff --git a/buildstream/element.py b/buildstream/element.py
index 6536d2582..4d3e1bc75 100644
--- a/buildstream/element.py
+++ b/buildstream/element.py
@@ -451,7 +451,7 @@ class Element(Plugin):
 
         return None
 
-    def node_subst_member(self, node, member_name, default=utils._sentinel):
+    def node_subst_member(self, node, member_name, default=_yaml._sentinel):
         """Fetch the value of a string node member, substituting any variables
         in the loaded value with the element contextual variables.
 
diff --git a/buildstream/plugin.py b/buildstream/plugin.py
index 9c5c0d8ca..1b021d4b4 100644
--- a/buildstream/plugin.py
+++ b/buildstream/plugin.py
@@ -321,7 +321,7 @@ class Plugin():
         provenance = _yaml.node_get_provenance(node, key=member_name)
         return str(provenance)
 
-    def node_get_member(self, node, expected_type, member_name, default=utils._sentinel):
+    def node_get_member(self, node, expected_type, member_name, default=_yaml._sentinel):
         """Fetch the value of a node member, raising an error if the value is
         missing or incorrectly typed.
 
diff --git a/buildstream/utils.py b/buildstream/utils.py
index 0bddb287d..c116797bd 100644
--- a/buildstream/utils.py
+++ b/buildstream/utils.py
@@ -654,10 +654,6 @@ def _pretty_size(size, dec_places=0):
     return "{size:g}{unit}".format(size=round(psize, dec_places), unit=unit)
 
 
-# A sentinel to be used as a default argument for functions that need
-# to distinguish between a kwarg set to None and an unset kwarg.
-_sentinel = object()
-
 # Main process pid
 _main_pid = os.getpid()