Complete the work started to allow None as default in _yaml.node_get()

This completes the work which was started in commit
3ba544b80f9f268be8ffe62fc8589b30212ec4a2 which only went half
way towards updating all the source code to be consistent and use
the new semantic which allows None values.

6 files changed, 16 insertions, 16 deletions

diff --git a/buildstream/plugins/elements/script.py b/buildstream/plugins/elements/script.py
index f4e705967..7769cd120 100644
--- a/buildstream/plugins/elements/script.py
+++ b/buildstream/plugins/elements/script.py
@@ -43,7 +43,7 @@ class ScriptElement(buildstream.ScriptElement):
     def configure(self, node):
         for n in self.node_get_member(node, list, 'layout', []):
             dst = self.node_subst_member(n, 'destination')
-            elm = self.node_subst_member(n, 'element', '') or None
+            elm = self.node_subst_member(n, 'element', None)
             self.layout_add(elm, dst)
 
         self.node_validate(node, [
diff --git a/buildstream/plugins/sources/_downloadablefilesource.py b/buildstream/plugins/sources/_downloadablefilesource.py
index fd7c7fac5..d9128ce3f 100644
--- a/buildstream/plugins/sources/_downloadablefilesource.py
+++ b/buildstream/plugins/sources/_downloadablefilesource.py
@@ -16,8 +16,8 @@ class DownloadableFileSource(Source):
 
     def configure(self, node):
         self.original_url = self.node_get_member(node, str, 'url')
-        self.ref = self.node_get_member(node, str, 'ref', '') or None
-        self.etag = self.node_get_member(node, str, 'etag', '') or None
+        self.ref = self.node_get_member(node, str, 'ref', None)
+        self.etag = self.node_get_member(node, str, 'etag', None)
         self.url = self.translate_url(self.original_url)
 
     def preflight(self):
@@ -37,8 +37,8 @@ class DownloadableFileSource(Source):
             return Consistency.RESOLVED
 
     def load_ref(self, node):
-        self.ref = self.node_get_member(node, str, 'ref', '') or None
-        self.etag = self.node_get_member(node, str, 'etag', '') or None
+        self.ref = self.node_get_member(node, str, 'ref', None)
+        self.etag = self.node_get_member(node, str, 'etag', None)
 
     def get_ref(self):
         # Report `None` value if we dont have a ref
diff --git a/buildstream/plugins/sources/bzr.py b/buildstream/plugins/sources/bzr.py
index 93db3463c..8c8d0c8c3 100644
--- a/buildstream/plugins/sources/bzr.py
+++ b/buildstream/plugins/sources/bzr.py
@@ -65,7 +65,7 @@ class BzrSource(Source):
 
         self.original_url = self.node_get_member(node, str, 'url')
         self.tracking = self.node_get_member(node, str, 'track')
-        self.ref = self.node_get_member(node, str, 'ref', '') or None
+        self.ref = self.node_get_member(node, str, 'ref', None)
         self.url = self.translate_url(self.original_url)
 
     def preflight(self):
@@ -85,7 +85,7 @@ class BzrSource(Source):
             return Consistency.RESOLVED
 
     def load_ref(self, node):
-        self.ref = self.node_get_member(node, str, 'ref', '') or None
+        self.ref = self.node_get_member(node, str, 'ref', None)
 
     def get_ref(self):
         return self.ref
diff --git a/buildstream/plugins/sources/deb.py b/buildstream/plugins/sources/deb.py
index eaf24d9a8..296102d51 100644
--- a/buildstream/plugins/sources/deb.py
+++ b/buildstream/plugins/sources/deb.py
@@ -56,7 +56,7 @@ class DebSource(TarSource):
     def configure(self, node):
         super().configure(node)
 
-        self.base_dir = self.node_get_member(node, str, 'base-dir', '') or None
+        self.base_dir = self.node_get_member(node, str, 'base-dir', None)
 
     def preflight(self):
         return
diff --git a/buildstream/plugins/sources/git.py b/buildstream/plugins/sources/git.py
index 97643439e..7ac6dc057 100644
--- a/buildstream/plugins/sources/git.py
+++ b/buildstream/plugins/sources/git.py
@@ -240,14 +240,14 @@ class GitMirror():
 class GitSource(Source):
 
     def configure(self, node):
-        ref = self.node_get_member(node, str, 'ref', '') or None
+        ref = self.node_get_member(node, str, 'ref', None)
 
         config_keys = ['url', 'track', 'ref', 'submodules', 'checkout-submodules']
         self.node_validate(node, config_keys + Source.COMMON_CONFIG_KEYS)
 
         self.original_url = self.node_get_member(node, str, 'url')
         self.mirror = GitMirror(self, '', self.original_url, ref)
-        self.tracking = self.node_get_member(node, str, 'track', '') or None
+        self.tracking = self.node_get_member(node, str, 'track', None)
         self.checkout_submodules = self.node_get_member(node, bool, 'checkout-submodules', True)
         self.submodules = []
 
@@ -258,7 +258,7 @@ class GitSource(Source):
         modules = self.node_get_member(node, Mapping, 'submodules', {})
         for path, _ in self.node_items(modules):
             submodule = self.node_get_member(modules, Mapping, path)
-            url = self.node_get_member(submodule, str, 'url', '') or None
+            url = self.node_get_member(submodule, str, 'url', None)
             self.submodule_overrides[path] = url
             if 'checkout' in submodule:
                 checkout = self.node_get_member(submodule, bool, 'checkout')
@@ -297,7 +297,7 @@ class GitSource(Source):
         return Consistency.INCONSISTENT
 
     def load_ref(self, node):
-        self.mirror.ref = self.node_get_member(node, str, 'ref', '') or None
+        self.mirror.ref = self.node_get_member(node, str, 'ref', None)
 
     def get_ref(self):
         return self.mirror.ref
diff --git a/buildstream/plugins/sources/ostree.py b/buildstream/plugins/sources/ostree.py
index 43ca873ec..bf72fa784 100644
--- a/buildstream/plugins/sources/ostree.py
+++ b/buildstream/plugins/sources/ostree.py
@@ -65,13 +65,13 @@ class OSTreeSource(Source):
 
         self.original_url = self.node_get_member(node, str, 'url')
         self.url = self.translate_url(self.original_url)
-        self.ref = self.node_get_member(node, str, 'ref', '') or None
-        self.tracking = self.node_get_member(node, str, 'track', '') or None
+        self.ref = self.node_get_member(node, str, 'ref', None)
+        self.tracking = self.node_get_member(node, str, 'track', None)
         self.mirror = os.path.join(self.get_mirror_directory(),
                                    utils.url_directory_name(self.url))
 
         # (optional) Not all repos are signed. But if they are, get the gpg key
-        self.gpg_key = self.node_get_member(node, str, 'gpg-key', '') or None
+        self.gpg_key = self.node_get_member(node, str, 'gpg-key', None)
         self.gpg_key_path = None
         if self.gpg_key is not None:
             self.gpg_key_path = os.path.join(self.get_project_directory(), self.gpg_key)
@@ -86,7 +86,7 @@ class OSTreeSource(Source):
         return [self.original_url, self.ref]
 
     def load_ref(self, node):
-        self.ref = self.node_get_member(node, str, 'ref', '') or None
+        self.ref = self.node_get_member(node, str, 'ref', None)
 
     def get_ref(self):
         return self.ref