Prior to this commit, the read() method in the IndexAccessor SPI
declared a return type of ValueRef which introduced a package cycle.
This commit addresses this by aligning with the PropertyAccess SPI and
returning TypedValue from IndexAccessor's read() method. This commit
also reworks the internals of Indexer based on a new, local
IndexAccessorValueRef implementation.
See gh-26409
See gh-26478
Prior to this commit, SpEL's CompoundExpression omitted the null-safe
syntax in AST string representations of indexing operations.
To address this, this commit implements isNullSafe() in Indexer.
See gh-29847
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, the SpEL compiler generated classes in a package
named "spel" with names following the pattern "Ex#", where # was an
index starting with 2.
This resulted in class names such as:
- spel.Ex2
- spel.Ex3
This commit improves the names of classes created by the SpEL compiler
by generating classes in a package named
"org.springframework.expression.spel.generated" with names following
the pattern "CompiledExpression#####", where ##### is a 0-padded
counter starting with 00001.
This results in class names such as:
- org.springframework.expression.spel.generated.CompiledExpression00001
- org.springframework.expression.spel.generated.CompiledExpression00002
This commit also moves the saveGeneratedClassFile() method from
SpelCompilationCoverageTests to SpelCompiler and enhances it to:
- Save classes in a "build/generated-classes" directory.
- Convert package names to directories.
- Create missing parent directories.
- Use logging instead of System.out.println().
Running a test with saveGeneratedClassFile() enabled now logs something
similar to the following.
DEBUG o.s.e.s.s.SpelCompiler - Saving compiled SpEL expression [(#root.empty ? 0 : #root.size)] to [/Users/<username>/spring-framework/spring-expression/build/generated-classes/org/springframework/expression/spel/generated/CompiledExpression00001.class]
Closes gh-32497
Commit c79436f832 ensured that methods are invoked via a public
interface or public superclass when compiling Spring Expression
Language (SpEL) expressions involving method references or property
access (see MethodReference, PropertyOrFieldReference, and
collaborating support classes). However, compilation of expressions
that access properties by indexing into an object by property name is
still not properly supported in all scenarios.
To address those remaining use cases, this commit ensures that methods
are invoked via a public interface or public superclass when accessing
a property by indexing into an object by the property name – for
example, `person['name']` instead of `person.name`.
In addition, SpEL's Indexer now properly relies on the
CompilablePropertyAccessor abstraction instead of hard-coding support
for only OptimalPropertyAccessor. This greatly reduces the complexity
of the Indexer and simultaneously allows the Indexer to potentially
support other CompilablePropertyAccessor implementations.
Closes gh-29857
Although the Spring Expression Language (SpEL) generally does a good
job of locating the public declaring class or interface on which to
invoke a method in a compiled expression, prior to this commit there
were still a few unsupported use cases.
To address those remaining use cases, this commit ensures that methods
are invoked via a public interface or public superclass whenever
possible when compiling SpEL expressions.
See gh-29857
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
Prior to this commit, the reference manual only documented indexing
support for arrays, lists, and maps.
This commit improves the overall documentation for SpEL's property
navigation and indexing support and introduces additional documentation
for indexing into Strings and Objects.
Closes gh-32355
Since the Spring Expression Language does not actually support local
variables in expressions, this commit deprecates all public APIs
related to local variables in ExpressionState (namely, the two
enterScope(...) variants that accept local variable data,
setLocalVariable(), and lookupLocalVariable()).
In addition, we no longer invoke `state.enterScope("index", ...)` in
the Projection and Selection AST nodes since the $index local variable
was never accessible within expressions anyway.
See gh-23202
Closes gh-32004
