Optimize Enum::detectConstants() by using assertion

[marc-mabe]

... on checking for ambiguous enumerator values.

This will speed up first enumeration call with a factor of ~3.

The BC break is because of it throws an AssertionError if zend.assertions = 1 or throws nothing.

[prolic]

Why not throw an exception here like before? I am kind of against using assertions.

[prolic]

I also see not why this should be so much faster.

[marc-mabe]

@prolic

Assertions should be enabled in development move only and is designed for cases that should be evaluate to true ever. So if an assertion fails it notifies a programming error. Such errors must be detected on development and assertions are not needed to execute on production.

Please run the following benchmark with 9019505 applied before

php -d 'zend.assertions=1' ./vendor/bin/phpbench run --context="master" --filter=benchGetConstants --report=aggregate

+-----------+-------------------+--------+--------+------+-----+----------+----------+----------+----------+----------+---------+--------+-------+
| benchmark | subject           | groups | params | revs | its | mem_peak | best     | mean     | mode     | worst    | stdev   | rstdev | diff  |
+-----------+-------------------+--------+--------+------+-----+----------+----------+----------+----------+----------+---------+--------+-------+
| EnumBench | benchGetConstants |        | []     | 2500 | 25  | 960,816b | 50.800μs | 51.402μs | 51.015μs | 52.034μs | 0.430μs | 0.84%  | 0.00% |
+-----------+-------------------+--------+--------+------+-----+----------+----------+----------+----------+----------+---------+--------+-------+

then comment out the code for assertions.

+-----------+-------------------+--------+--------+------+-----+----------+----------+----------+----------+----------+---------+--------+-------+
| benchmark | subject           | groups | params | revs | its | mem_peak | best     | mean     | mode     | worst    | stdev   | rstdev | diff  |
+-----------+-------------------+--------+--------+------+-----+----------+----------+----------+----------+----------+---------+--------+-------+
| EnumBench | benchGetConstants |        | []     | 2500 | 25  | 958,928b | 13.757μs | 13.975μs | 13.971μs | 14.154μs | 0.097μs | 0.69%  | 0.00% |
+-----------+-------------------+--------+--------+------+-----+----------+----------+----------+----------+----------+---------+--------+-------+

[prolic]

Understand, great idea!