alhudz opened a new pull request, #1807:
URL: https://github.com/apache/commons-lang/pull/1807
`TypeUtils.wildcardType().build()` (a wildcard with no explicit upper bound,
and likewise a `withLowerBounds`-only wildcard) stores an empty upper-bounds
array, so `getUpperBounds()` returns `[]`. The
`java.lang.reflect.WildcardType.getUpperBounds()` contract says the implicit
upper bound is `Object` when none is declared, which is what the JDK's own `?`
and this class's `getImplicitUpperBounds` both report. Because of the mismatch
`equals` is asymmetric across implementations: `built.equals(jdkWildcard)` is
`true` (our `equals` normalises the empty array to `Object`) while
`jdkWildcard.equals(built)` is `false` (the JDK compares the raw bounds
arrays), and `built.hashCode()` disagrees with `WILDCARD_ALL.hashCode()`
although the two are equal.
Default the stored upper bounds to `Object` in the `WildcardTypeImpl`
constructor so `getUpperBounds()`, `equals()` and `hashCode()` all line up with
the JDK. Keeping it in the constructor is what makes the three agree from one
place; explicitly bounded wildcards and `WILDCARD_ALL` are untouched, and
`toString()` still renders `?` because the formatter already treats an `Object`
upper bound as unbounded.
Repro:
WildcardType built = TypeUtils.wildcardType().build();
WildcardType jdk = /* the ? taken from a List<?> field via reflection
*/;
Expected: `built.getUpperBounds()` is `[Object.class]`; `jdk.equals(built)`
is `true`
Actual (before): `built.getUpperBounds()` is `[]`; `jdk.equals(built)` is
`false`
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the test and this description; I reviewed and verified everything and ran the
full `mvn` build locally.
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