This change is as per RFC https://wiki.php.net/rfc/empty_isset_exprs.
The change allows passing the result of function calls and other
expressions to the empty() language construct. This is accomplished by
simply rewriting empty(expr) to !expr.
The change does not affect the suppression of errors when using empty()
on variables. empty($undefinedVar) will continue not to throw errors.
When an expression is used inside empty() on the other hand, errors will
not be suppressed. Thus empty($undefinedVar + $somethingElse) *will*
throw a notice.
The change also does not make empty() into a real function, so using
'empty' as a callback is still not possible.
In addition to the empty() changes the commit adds nicer error messages
when isset() is used on function call results or other expressions.
This fixes bug #60097.
Before two global variables CG(heredoc) and CG(heredoc_len) were used to
track the current heredoc label. In order to support nested heredoc
strings the *previous* heredoc label was assigned as the token value of
T_START_HEREDOC and the language_parser.y assigned that to CG(heredoc).
This created a dependency of the lexer on the parser. Thus the
token_get_all() function, which accesses the lexer directly without
also running the parser, was not able to tokenize nested heredoc strings
(and leaked memory). Same applies for the source-code highlighting
functions.
The new approach is to maintain a heredoc_label_stack in the lexer, which
contains all active heredoc labels.
As it is no longer required, T_START_HEREDOC and T_END_HEREDOC now don't
carry a token value anymore.
In order to make the work with zend_ptr_stack in this context more
convenient I added a new function zend_ptr_stack_top(), which retrieves the
top element of the stack (similar to zend_stack_top()).
# __TRAIT__ behaves like __CLASS__ more or less but is constraint to traits.
# Since traits are not types, there are not many valid use cases, and trying
# to use __TRAIT__ to make traits more like classes is discouraged.
# __TRAIT__ behaves like __CLASS__ more or less but is constraint to traits.
# Since traits are not types, there are not many valid use cases, and trying
# to use __TRAIT__ to make traits more like classes is discouraged.
# RFC http://wiki.php.net/rfc/horizontalreuse#traits_-_reuse_of_behavior
# Ok, here we go, I guess that will result in more discussion, which is fine
# by me. But now, the patch is here, and properly archived.
#
# See below a list of notes to the patch, it also includes a list of
# points which should be fixed
#
# Internals of the Traits Patch
# -----------------------------
#
# Open TODOs
# """"""""""
#
# - Reflection API
# - support for traits for internal classes
# - currently destroy_zend_class does not handle that case
#
# Introduced Structures
# """""""""""""""""""""
#
# Data structures to encode the composition information specified in the
# source:
# - zend_trait_method_reference
# - zend_trait_precedence
# - zend_trait_alias
#
# Changes
# """""""
#
# zend_class_entry
# - uses NULL terminated lists of pointers for
# - trait_aliases
# - trait_precedences
# - do you prefer an explicit counter?
# - the information is only necessary during class composition
# but might be interesting for reflection
# - did not want to blow up class further with not really necessary length counters
#
# added keywords
# - trait
# - insteadof
#
# Added opcodes
# ZEND_ADD_TRAIT
# - similar to ZEND_ADD_INTERFACE
# - adds the trait to the list of traits of a class, no actual composition done
# ZEND_BIND_TRAITS
# - emitted in zend_do_end_class_declaration
# - concludes the class definition and will initiate the trait composition
# when the class definition is encountered during runtime
#
# Added Flags
# ZEND_ACC_TRAIT = 0x120
# ZEND_ACC_IMPLEMENT_TRAITS = 0x400000
# ZEND_FETCH_CLASS_TRAIT = 14
#
# zend_vm_execute.h
# - not sure whether the handler initialization (ZEND_ADD_TRAIT_SPEC_HANDLER,
# ZEND_BIND_TRAITS_SPEC_HANDLER) is correct, maybe it should be more selective
#
# zend_compile.c
# - refactored do_inherit_method_check
# split into do_inherit_method_check and do_inheritance_check_on_method
# - added helper functions use a '_' as prefix and are not mentioned in the
# headers
# - _copy_functions
# prepare hash-maps of functions which should be merged into a class
# here the aliases are handled
# - _merge_functions
# builds a hash-table of the methods which need to be added to a class
# does the conflict detection
# - reused php_runkit_function_copy_ctor
# - it is not identical with the original code anymore, needed to update it
# think I fixed some bugs, not sure whether all have been reported back to runkit
# - has to be renamed, left the name for the moment, to make its origin obvious
# - here might be optimization potential
# - not sure whether everything needs to be copied
# - copying the literals might be broken
# - added it since the literals array is freed by efree and gave problems
# with doubled frees
# - all immutable parts of the zend_op array should not be copied
# - am not sure which parts are immutable
# - and not sure how to avoid doubled frees on the same arrays on shutdown
# - _merge_functions_to_class
# does the final merging with the target class to handle inherited
# and overridden methods
# - small helper for NULL terminated lists
# zend_init_list, zend_add_to_list
#
# zend_language_parser.y
# - reused class definition for traits
# - there should be something with regard to properties
# - if they get explicitly defined, it might be worthwhile to
# check that there are no collisions with other traits in a composition
# (however, I would not introduce elaborate language features to control that
# but a notice for such conflicts might be nice to the developers)
. ZEND_RECV now always has IS_CV as its result
. ZEND_CATCH now has to be used only with constant class names
. ZEND_FETCH_DIM_? may fetch array and dimension operans in a different order
