gnodet opened a new pull request, #13877:
URL: https://github.com/apache/maven/pull/13877
## Summary
Fix `InjectorImpl` to return an empty collection when `getInstance()` is
called
with `Key<List<T>>` or `Key<Map<String,T>>` and no bindings are registered
for
the element type `T`.
## Root Cause
`InjectorImpl.doGetCompiledBinding()` handles `List<T>` and `Map<String,T>`
keys
by calling `getBindings(elementType)`. When this returns `null` (no bindings
registered at all for that type), the code fell through to the generic
`throw new DIException("No binding to construct an instance for key ...")`.
This violated the documented contract of `Lookup.lookupList()` and
`Lookup.lookupMap()`, which both state _"The collection may be empty if no
components are found"_ — an absent type should yield an empty collection, not
an exception.
The `ApiRunner` implementation worked around this by catching `DIException`
and
returning `List.of()`. However, that catch was too broad (it would also
suppress
genuine provisioning errors) and masked the real bug in `InjectorImpl`. It
also
used a raw anonymous `Key<List<T>>(){}` subclass whose type parameter is
erased
at runtime, so lookups never found the correct bindings anyway.
## Fix
**`InjectorImpl`**: when `getBindings(elementType)` returns `null` in the
`List<T>` path, return an empty list supplier instead of falling through to
the
exception. Same for `Map<String,T>`.
**`ApiRunner`**: replace the anonymous `new Key<List<T>>() {}` (type-erased)
with `Key.ofType(Types.parameterizedType(List.class, type))` (correctly
parameterized). Remove the `try/catch (DIException)` workaround — no longer
needed.
## Impact
- `Lookup.lookupList()` and `Lookup.lookupMap()` now consistently return
empty
collections when no bindings are registered, on all `Lookup`
implementations.
- `ExtensibleEnumRegistries` and `DefaultTypeRegistry`, which both call
`lookupList()`, are now robust when no `TypeProvider` is registered.
- No behavioral regression: code that relied on the `DIException` to detect
"nothing registered" was already broken (it was catching a contract
violation).
_Hermes Agent (Claude Sonnet 4.6) on behalf of Guillaume Nodet_
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