With this change the code generation for method and property
references is modified to include branching logic in the
case of null safe dereferencing (?.). This is complicated
by the possible usage of primitives on the left hand side
of the dereference. To cope with this case primitives are
promoted to boxed types when this situation occurs enabling
null to be passed as a possible result.
Issue: SPR-16489
Without this fix the compiled version of elvis
actual behaved differently to the interpreted version
if the value being queried was an empty string. This
is now fixed. It also now correctly handles the
query value being a primitive and addresses the
findings of SPR-15192 where some type inferencing
logic was trying to be too clever, that code has
been deleted.
Issue: SPR-15192
(cherry picked from commit d41d28f)
For SPR-14863 we need to adjust the code generation for OpNE
to use !x.equals(y) rather than x!=y. There are also further
cases in the equalityCheck() code in Operator that were not
being handled in the compilation case (when comparators are
used for example). This latter issue also affects OpEQ.
Rather than add yet more bytecode generation, both OpNE and
OpEQ generateCode() methods have been simplified. The
generated code now delegates to equalityCheck() in Operator
which is exactly what the interpreted case does.
This ensures that the compiled code continues to behave just
like the interpreted case. It ensures changes to the interpreted
case are automatically picked up for the compiled case. It
makes the bytecode generation simpler.
The benefit of compilation of SpEL expressions is to avoid
slow reflective calls - that doesn't apply for a basic
(in)equality test so there is no need to go crazy in bytecode
gen.
Issue: SPR-14863
(cherry picked from commit 9000acd)
Prior to this commit the SpEL compiler would generate bad bytecode
if the left hand operand of an instanceof was a primitive or
if the right hand operand was a primitive type reference.
With the fixes primitives on the left hand side are now
correctly boxed and special handling is in place for when the
right hand side is a primitive type reference. Using a primitive
type reference on the right always causes the instanceof
check to return false.
Additionally a guard has been added such that compilation is
not allowed when the right hand side of an expression
is not a type reference. If it is, for example, a variable
reference that evaluates to a type reference then that
cannot be expressed in bytecode so compilation is not performed.
Issue: SPR-14250
Juergen Hoeller