1 files changed, 50 insertions, 0 deletions
diff --git a/src/data/composite/things/track/inheritFromOriginalRelease.js b/src/data/composite/things/track/inheritFromOriginalRelease.js
new file mode 100644
index 0000000..27ed138
--- /dev/null
+++ b/src/data/composite/things/track/inheritFromOriginalRelease.js
@@ -0,0 +1,50 @@
+// Early exits with a value inherited from the original release, if
+// this track is a rerelease, and otherwise continues with no further
+// dependencies provided. If allowOverride is true, then the continuation
+// will also be called if the original release exposed the requested
+// property as null.
+//
+// Like withOriginalRelease, this will early exit (with notFoundValue) if the
+// original release is specified by reference and that reference doesn't
+// resolve to anything.
+
+import {input, templateCompositeFrom} from '#composite';
+
+import withOriginalRelease from './withOriginalRelease.js';
+
+export default templateCompositeFrom({
+  annotation: `inheritFromOriginalRelease`,
+
+  inputs: {
+    property: input({type: 'string'}),
+    allowOverride: input({type: 'boolean', defaultValue: false}),
+    notFoundValue: input({defaultValue: null}),
+  },
+
+  steps: () => [
+    withOriginalRelease({
+      notFoundValue: input('notFoundValue'),
+    }),
+
+    {
+      dependencies: [
+        '#originalRelease',
+        input('property'),
+        input('allowOverride'),
+      ],
+
+      compute: (continuation, {
+        ['#originalRelease']: originalRelease,
+        [input('property')]: originalProperty,
+        [input('allowOverride')]: allowOverride,
+      }) => {
+        if (!originalRelease) return continuation();
+
+        const value = originalRelease[originalProperty];
+        if (allowOverride && value === null) return continuation();
+
+        return continuation.exit(value);
+      },
+    },
+  ],
+});