Make inspecting SplFixedArray instances more memory efficient/consistent, change print_r null props handling

[TysonAndre]

• Print objects with null hash table like others in print_r

  Noticed when working on subsequent commits for SplFixedArray.
  Make whether zend_get_properties_for returns null or an empty array
  invisible to the end user - it would be always be a non-null array for
  user-defined classes.

• Make handling of SplFixedArray properties more consistent

  Create a brand new reference counted array every time in SplFixedArray
  to be freed by the callers (or return null).

  There were various inconsistencies in SplFixedArray that this fixes, (which required improvements only available in 8.3 from PRs I merged):

  • Calling var_export/var_dump/array cast/print_r on an SplFixedArray directly/indirectly would increase its memory usage by allocating and populating its property table
  • Calling destructors on values found in an SplFixedArray would be delayed if those properties were found in the most recent call to var_export/var_dump/etc
  • The properties table does not need to be created (increasing memory usage) then returned to get_gc if there are no dynamic object properties (similar to the implementation of zend_std_get_gc)

"object properties" refers to $splFixedArray->prop
"array elements" refers to $splFixedArray[$offset]

This approach is similar to the one used for final class Collections\Deque, but also needs to account for the fact that SplFixedArray allows dynamic properties, can be subclassed, and those subclasses will be able to have #[AllowDynamicProperties] even in php 9.0. #7500

Also see https://github.com/php/php-src/pull/9703/files (PRs have no dependencies can be merged independently if approved)

For datastructures such as SplFixedArray, the call to get_properties currently also takes time and may have side effects(destructors), because it needs to update/delete the values to match the backing array. Maybe SplFixedArray and similar datastructures should switch to get_properties_for, so that get_mangled_object_props returns only properties and not fields

---

References

This is unrelated to 9697, but I wrote up what seems to be the requirements for properly implementing get_properties and get_properties_for handlers that will work correctly with the various internal functionality of php-src in #9697 (comment) . This was used when working on https://github.com/TysonAndre/pecl-teds/ and its unit tests, as well as the Deque RFC implementation #7500

[TysonAndre]

Test failures seem spurious and unrelated

ext/pdo_oci/tests/oci_success_with_info.phpt (github, click to expand)

       [2]=>
       string(%d) "OCISessionBegin: OCI_SUCCESS_WITH_INFO: ORA-28002: %s
      (%s:%d)"
010+ 
011+ Warning: PDO::exec(): SQLSTATE[HY000]: General error: 1940 OCIStmtExecute: ORA-01940: cannot drop a user that is currently connected
012+ ORA-06512: at line 6
013+ ORA-06512: at line 2
014+  (/home/runner/work/php-src/php-src/ext/pdo_oci/oci_driver.c:342) in /home/runner/work/php-src/php-src/ext/pdo_oci/tests/oci_success_with_info.php on line 26
     array(3) {
       [0]=>
       string(5) "HY000"

sapi/fpm/tests/status-listen.phpt (travis, click to expand)

========DIFF======== 001+ ERROR: Expected body does not match pattern 001- Done 002+ BODY: 003+ string(377) "pool: unconfined 004+ process manager: static 005+ start time: 15/Oct/2022:20:20:12 +0000 006+ start since: 0 007+ accepted conn: 1 008+ listen queue: 0 009+ max listen queue: 0 010+ listen queue len: 4096 011+ idle processes: 0 012+ active processes: 1 013+ total processes: 1 014+ max active processes: 1 015+ max children reached: 0 016+ slow requests: 0" 017+ PATTERN: 018+ string(345) "(pool:\s+unconfined 019+ process manager:\s+static 020+ start time:\s+\d+\/\w{3}\/\d{4}:\d{2}:\d{2}:\d{2}\s[+-]\d{4} 021+ start since:\s+\d+ 022+ accepted conn:\s+\d+ 023+ listen queue:\s+0 024+ max listen queue:\s+0 025+ listen queue len:\s+\d+ 026+ idle processes:\s+1 027+ active processes:\s+0 028+ total processes:\s+1 029+ max active processes:\s+1 030+ max children reached:\s+0 031+ slow requests:\s+0)" 032+ Done ========DONE======== FAIL FPM: Status listen test [sapi/fpm/tests/status-listen.phpt]

[Girgias]

SPL changes LGTM, and I don't really care about the changes to print_r but some might disagree.

[dstogov]

I don't see problems.

[dstogov]

Why is this necessary?

[TysonAndre]

Overloaded object of type DateInterval is not compatible with ArrayObject

ArrayObject checks if get_properties_handler is overloaded and throws if it is.

After my change to spl_fixedarray.c, the get_properties handler of SplFixedArray is no longer overloaded.

So I changed to DateInterval, which continues to overload the get_properties handler

[TysonAndre]

Build failures are unrelated.

1ea8c82 fixed the unrelated spurious travis build failure https://ci.appveyor.com/project/php/php-src/builds/45155001/job/767ocx20lg4y70vg

the spurious php-fpm test failure is a known issue https://app.travis-ci.com/github/php/php-src/jobs/586419479