This commit introduces two tests to verify the status quo.
- mapAccessThroughIndexerForNonexistentKey(): demonstrates that map
access via the built-in support in the Indexer returns `null` for a
nonexistent key.
- nullAwareMapAccessor(): demonstrates that users can implement and
register a custom extension of MapAccessor which reports that it can
read any map (ignoring whether the map actually contains an entry for
the given key) and returns `null` for a nonexistent key.
See gh-35534
Prior to this commit, the MapAccessor for SpEL resided in the
org.springframework.context.expression package in the spring-context
module; however, it arguably should reside in the spring-expression
module so that it can be used whenever SpEL is used (without requiring
spring-context).
This commit therefore officially deprecates the MapAccessor in
spring-context for removal in favor of a new copy of the implementation
in the org.springframework.expression.spel.support package in the
spring-expression module.
Closes gh-35537
We have had an ObjectToOptionalConverter since Spring Framework 4.1;
however, prior to this commit we did not have a standard Converter for
the inverse (Optional to Object).
To address that, this commit introduces an OptionalToObjectConverter
that unwraps an Optional, using the ConversionService to convert the
object contained in the Optional (potentially null) to the target type.
This allows for conversions such as the following.
- Optional.empty() -> null
- Optional.of(42) with Integer target -> 42
- Optional.of(42) with String target -> "42"
- Optional.of(42) with Optional<String> target -> Optional.of("42")
The OptionalToObjectConverter is also registered by default in
DefaultConversionService, alongside the existing
ObjectToOptionalConverter.
See gh-20433
Closes gh-34544
This commit removes the BDDMockito Checkstyle rule, since it did not
actually enforce the use of BDDMockito.
This commit also updates static imports to use Mockito instead of
BDDMockito where appropriate (automated via the Eclipse IDE Organize
Imports clean-up task).
Closes gh-34616
This commit introduces null-safe support for java.util.Optional in the
following SpEL operators:
- PropertyOrFieldReference
- MethodReference
- Indexer
- Projection
- Selection
- Elvis
Specifically, when a null-safe operator is applied to an empty
`Optional`, it will be treated as if the `Optional` were `null`, and
the subsequent operation will evaluate to `null`. However, if a
null-safe operator is applied to a non-empty `Optional`, the subsequent
operation will be applied to the object contained in the `Optional`,
thereby effectively unwrapping the `Optional`.
For example, if `user` is of type `Optional<User>`, the expression
`user?.name` will evaluate to `null` if `user` is either `null` or an
empty `Optional` and will otherwise evaluate to the `name` of the
`user`, effectively `user.get().getName()` for property access.
Note, however, that invocations of methods defined in the `Optional`
API are still supported on an empty `Optional`. For example, if `name`
is of type `Optional<String>`, the expression `name?.orElse('Unknown')`
will evaluate to "Unknown" if `name` is an empty `Optional` and will
otherwise evaluate to the `String` contained in the `Optional` if
`name` is a non-empty `Optional`, effectively `name.get()`.
Closes gh-20433
Prior to this commit, if an appropriate Converter was registered with
the ConversionService that converts from a POJO to an array and that
ConversionService was registered with the Spring Expression Language
(SpEL) TypeConverter, an attempt to invoke a varargs method in a SpEL
expression with such a POJO would fail because the ConversionService
was not used to convert the POJO to an array suitable for the varargs
method invocation.
This commit revises the implementations of convertArguments(...) and
convertAllMethodHandleArguments(...) in ReflectionHelper to support
such use cases.
Closes gh-34371
This commit updates the whole Spring Framework codebase to use JSpecify
annotations instead of Spring null-safety annotations with JSR 305
semantics.
JSpecify provides signficant enhancements such as properly defined
specifications, a canonical dependency with no split-package issue,
better tooling, better Kotlin integration and the capability to specify
generic type, array and varargs element null-safety. Generic type
null-safety is not defined by this commit yet and will be specified
later.
A key difference is that Spring null-safety annotations, following
JSR 305 semantics, apply to fields, parameters and return values,
while JSpecify annotations apply to type usages. That's why this
commit moves nullability annotations closer to the type for fields
and return values.
See gh-28797
Prior to this commit, if a MethodHandle was registered as a custom
function in the Spring Expression Language (SpEL) for a static method
that accepted only a variable argument list (for example,
`static String func(String... args)`), attempting to invoke the
registered function within a SpEL expression resulted in a
ClassCastException because the varargs array was unnecessarily wrapped
in an Object[].
This commit modifies the logic in FunctionReference's internal
executeFunctionViaMethodHandle() method to address that.
Closes gh-34109
Prior to this commit, the SpEL Tokenizer threw an IllegalStateException
when an unsupported character was detected in a SpEL expression;
however, the Javadoc for ExpressionParser.parseExpression() states that
it throws a ParseException if an exception occurred during parsing.
This commit addresses that issue by throwing a SpelParseException for
an unsupported character in a SpEL expression, using a new
UNSUPPORTED_CHARACTER enum constant in SpelMessage.
Closes gh-33767
Prior to this commit, when invoking init methods and destroy methods
for beans as well as methods within Spring Expression Language (SpEL)
expressions via reflection, we invoked them based on the "interface
method" returned from ClassUtils.getInterfaceMethodIfPossible(). That
works well for finding methods defined in an interface, but it does not
find public methods defined in a public superclass.
For example, in a SpEL expression it was previously impossible to
invoke toString() on a non-public type from a different module. This
could be seen when attempting to invoke toString() on an unmodifiable
list created by Collections.unmodifiableList(...). Doing so resulted in
an InaccessibleObjectException.
Although users can address that by adding an appropriate --add-opens
declaration, such as --add-opens java.base/java.util=ALL-UNNAMED, it is
better if applications do not have to add an --add-opens declaration
for such use cases in SpEL. The same applies to init methods and
destroy methods for beans.
This commit therefore introduces a new
getPubliclyAccessibleMethodIfPossible() method in ClassUtils which
serves as a replacement for getInterfaceMethodIfPossible().
This new method finds the first publicly accessible method in the
supplied method's type hierarchy that has a method signature equivalent
to the supplied method. If the supplied method is public and declared
in a public type, the supplied method will be returned. Otherwise, this
method recursively searches the class hierarchy and implemented
interfaces for an equivalent method that is public and declared in a
public type. If a publicly accessible equivalent method cannot be
found, the supplied method will be returned, indicating that no such
equivalent method exists.
All usage of getInterfaceMethodIfPossible() has been replaced with
getPubliclyAccessibleMethodIfPossible() in spring-beans and
spring-expression. In addition, getInterfaceMethodIfPossible() has been
marked as deprecated in favor of the new method.
As a bonus, the introduction of getPubliclyAccessibleMethodIfPossible()
allows us to delete a fair amount of obsolete code within the SpEL
infrastructure.
See gh-29857
Closes gh-33216
SimpleEvaluationContext.forReadOnlyDataBinding() documents that it
creates a SimpleEvaluationContext for read-only access to public
properties; however, prior to this commit write access was not disabled
for indexed structures when using the assignment operator, the
increment operator, or the decrement operator.
In order to better align with the documented contract for
forReadOnlyDataBinding(), this commit makes it possible to disable
assignment in general in order to enforce read-only semantics for
SpEL's SimpleEvaluationContext when created via the
forReadOnlyDataBinding() factory method. Specifically:
- This commit introduces a new isAssignmentEnabled() "default" method
in the EvaluationContext API, which returns true by default.
- SimpleEvaluationContext overrides isAssignmentEnabled(), returning
false if the context was created via the forReadOnlyDataBinding()
factory method.
- The Assign, OpDec, and OpInc AST nodes -- representing the assignment
(=), increment (++), and decrement (--) operators, respectively --
now throw a SpelEvaluationException if assignment is disabled for the
current EvaluationContext.
Closes gh-33319
The changes made in conjunction with gh-33013 resulted in a regression
for varargs support in SpEL expressions. Specifically, before gh-33013
one could supply a list -- for example, an "inline list" -- as the
varargs array when invoking a varargs constructor, method, or function
within a SpEL expression. However, after gh-33013 an inline list (or
collection in general) is no longer converted to an array for varargs
invocations. Instead, the list is supplied as a single argument of the
resulting varargs array which breaks applications that depend on the
previous behavior.
Although it was never intended that one could supply a collection as
the set of varargs, we concede that this is a regression in existing
behavior, and this commit therefore restores support for supplying a
java.util.List as the varargs "array".
In addition, this commit introduces the same "list to array" conversion
support for MethodHandle-based functions that accept varargs.
Note, however, that this commit does not restore support for converting
arbitrary single objects to an array for varargs invocations if the
single object is already an instance of the varargs array's component
type.
See gh-33013
Closes gh-33315
Prior to this commit, the Indexer in the Spring Expression Language
(SpEL) silently ignored a failure to set a property via the indexed
property syntax (['<property name>'] = <new value>) – for example, if
property write access was disabled in the EvaluationContext.
This commit addresses this issue by properly throwing a
SpelEvaluationException in PropertyIndexingValueRef.setValue(Object) if
the property could not be set.
Closes gh-33310
Prior to this commit, SpEL incorrectly wrapped a primitive array in an
Object[] array when invoking Object[] varargs methods and constructors.
This commit addresses this by updating the convertArguments(...) method
in ReflectionHelper as follows when the user supplies the varargs
already packaged in a primitive array.
- When deciding whether to convert a single element passed as varargs,
we now check if the argument is an array that is assignable to the
varargs array type.
- When converting an array supplied as the varargs, we convert that
array to the varargs array type.
Closes gh-33317
The internal ArgumentsMatchInfo type seems to have once had additional
methods beyond the functionality provided by the ArgumentsMatchKind
enum; however, that is no longer the case. Consequently, there is no
need to maintain both types.
This commit therefore merges the convenience methods from
ArgumentsMatchInfo into the ArgumentsMatchKind enum and removes the
unnecessary ArgumentsMatchInfo type.
Prior to this commit, the Spring Expression Language (SpEL) could not
invoke a varargs MethodHandle function with a primitive array
containing the variable arguments, although that is supported for a
varargs Method function. Attempting to do so resulted in the first
element of the primitive array being supplied as a single argument to
the MethodHandle, effectively ignoring any variable arguments after the
first one.
This commit addresses this by updating the
convertAllMethodHandleArguments(...) method in ReflectionHelper as
follows when the user supplies the varargs already packaged in a
primitive array.
- Regarding conversion, use the wrapper type for a primitive varargs
array, since we eventually need an Object array in order to invoke
the MethodHandle in FunctionReference#executeFunctionViaMethodHandle().
- When deciding whether to convert a single element passed as varargs,
we now check if the argument is an array that is assignable to the
varargs array type.
- When converting an array supplied as the varargs, we now convert that
array to the varargs array type instead of the varargs component type.
Note, however, that a SpEL expression cannot provide a primitive array
for an Object[] varargs target. This is due to the fact that the
ArrayToArrayConverter used by Spring's ConversionService does not
support conversion from a primitive array to Object[] -- for example,
from int[] to Object[].
See gh-33191
Closes gh-33198
Prior to this commit, the Spring Expression Language (SpEL) could not
invoke a varargs MethodHandle function with an array containing the
variable arguments, although that is supported for a varargs Method
function. Attempting to do so resulted in the array being supplied as a
single argument to the MethodHandle.
This commit addresses this by updating the
executeFunctionViaMethodHandle(...) method in FunctionReference as
follows when the user supplies the varargs already packaged in an array.
- Creates a new array large enough to hold the non-varargs arguments
and the unpackaged varargs arguments.
- Adds the non-varargs arguments to the beginning of that array and
adds the unpackaged varargs arguments to the end of that array.
- Invokes the MethodHandle with the new arguments array.
Closes gh-33191
Prior to this commit, the Spring Expression Language (SpEL) could not
invoke a varargs MethodHandle function with zero variable arguments,
even though the variable arguments are not required. Attempting to do
so resulted in a SpelEvaluationException with an
INCORRECT_NUMBER_OF_ARGUMENTS_TO_FUNCTION message.
This commit addresses this by updating the
executeFunctionViaMethodHandle(...) method in FunctionReference so that
it properly checks the required number of arguments for both varargs
and non-varargs MethodHandle invocations.
This commit also improves the error message for varargs invocations
with too few arguments. For example, if the MethodHandle requires at
least 1 argument plus a variable number of additional arguments and 0
arguments were supplied, the error message now states:
"Incorrect number of arguments for function 'myFunc': 0 supplied but function takes 1 or more"
Instead of:
"Incorrect number of arguments for function 'myFunc': 0 supplied but function takes 2"
Closes gh-33190
Tran Ngoc Nhan
rstoyanchev
Sam Brannen
Sébastien Deleuze
Spring Builds
Sébastien Deleuze
Juergen Hoeller