breadcrumbs property
Ordered labels naming the pipeline node(s) that produced this Err.
Populated by `.named(label)` in the order the chain saw them — the
first entry is the originally-failing step. Empty when no .named()
scope has tagged the error.
Example:
final out = fetchUser(id).named('fetch')
.map(parseJson).named('parse')
.map(extractCfg).named('extract');
switch (await out.value) {
case Err(:final breadcrumbs):
print('failed at: ${breadcrumbs.join(" → ")}');
case Ok():
// ...
}
Implementation
final List<String> breadcrumbs;