Only validate property value type if we care about the property

src/feature-flags/properties.test.ts

@@ -64,6 +64,29 @@ test.serial(
   },
 );
 
+test.serial(
+  "loadPropertiesFromApi does not throw for unexpected value types of unknown properties",
+  async (t) => {
+    sinon.stub(api, "getRepositoryProperties").resolves({
+      headers: {},
+      status: 200,
+      url: "",
+      data: [{ property_name: "not-used-by-us", value: { foo: "bar" } }],
+    });
+    const logger = getRunnerLogger(true);
+    const mockRepositoryNwo = parseRepositoryNwo("owner/repo");
+    await t.notThrowsAsync(
+      properties.loadPropertiesFromApi(
+        {
+          type: util.GitHubVariant.DOTCOM,
+        },
+        logger,
+        mockRepositoryNwo,
+      ),
+    );
+  },
+);
+
 test.serial(
   "loadPropertiesFromApi returns empty object if on GHES",
   async (t) => {

src/feature-flags/properties.ts

@@ -85,13 +85,15 @@ export async function loadPropertiesFromApi(
         );
       }
 
-      if (typeof property.value !== "string") {
-        throw new Error(
-          `Expected repository property '${property.property_name}' to have a string value, but got: ${JSON.stringify(property)}`,
-        );
-      }
-
       if (isKnownPropertyName(property.property_name)) {
+        // Only validate the type of `value` if this is a property we care about, to avoid throwing
+        // on unrelated properties that may use representations we do not support.
+        if (typeof property.value !== "string") {
+          throw new Error(
+            `Expected repository property '${property.property_name}' to have a string value, but got: ${JSON.stringify(property)}`,
+          );
+        }
+
         setProperty(properties, property.property_name, property.value, logger);
       }
     }