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
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
This commit ensures that the varargs component type for a MethodHandle
cannot be null in ReflectionHelper's
convertAllMethodHandleArguments(...) method in SpEL.
Closes gh-33193
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
Prior to this commit, the Spring Expression Language (SpEL) incorrectly
split single String arguments by comma for Object... varargs method and
constructor invocations.
This commit addresses this by checking if the single argument type is
already "assignable" to the varargs component type instead of "equal"
to the varargs component type.
Closes gh-33013
Prior to this commit, the Spring Expression Language (SpEL) failed to
compile an expression that indexed into a Map using a primitive literal
(boolean, int, long, float, or double).
This commit adds support for compilation of such expressions by
ensuring that primitive literals are boxed into their corresponding
wrapper types in the compiled bytecode.
Closes gh-32903
Prior to this commit, the Spring Expression Language (SpEL) failed to
compile an expression that indexed into any array or list using an
Integer.
This commit adds support for compilation of such expressions by
ensuring that an Integer is unboxed into an int in the compiled
bytecode.
See gh-32694
Closes gh-32908
Prior to this commit, SpEL's CompoundExpression omitted the null-safe
syntax in AST string representations of the selection and projection
operators.
To address this, this commit implements isNullSafe() in Projection and
Selection.
Closes gh-32515
Prior to this commit, MethodReference and PropertyOrFieldReference
already defined local isNullSafe() methods, but we need identical
methods in Selection, Projection, and Indexer, and we may potentially
need null-safe support for additional operators in the future.
To address the common need for an is-null-safe check, this commit
introduces an isNullSafe() method in SpelNodeImpl with a default
implementation that returns false.
Closes gh-32516
Prior to this commit, if a Spring Expression Language (SpEL) expression
referenced the root context object via the #root or #this variable, we
inserted a checkcast in the generated byte code that cast the object to
its concrete type. However if the root context object's type was
non-public, that resulted in an IllegalAccessError when the compiled
byte code was executed.
VariableReference.getValueInternal() already contains a solution for
global variables which inserts a checkcast to Object in the generated
byte code instead of to the object's concrete non-public type.
This commit therefore applies the same logic to #root (or #this when
used to reference the root context object) that is already applied to
global variables.
Closes gh-32356
Although EvaluationContext defines the API for setting and looking up
variables, the internals of the Spring Expression Language (SpEL)
actually provide explicit support for registering functions as
variables.
This is self-evident in the two registerFunction() variants in
StandardEvaluationContext; however, functions can also be registered as
variables when using the SimpleEvaluationContext.
Since custom functions are also viable in use cases involving the
SimpleEvaluationContext, this commit documents that functions may be
registered in a SimpleEvaluationContext via setVariable().
This commit also explicitly documents the "function as a variable"
behavior in the class-level Javadoc for both StandardEvaluationContext
and SimpleEvaluationContext, as well as in the reference manual.
Closes gh-32258
Sam Brannen
Mikaël Francoeur
Sébastien Deleuze
Juergen Hoeller
Stéphane Nicoll
Maksim Sasnouski