[RFC] Only unserialize Phar metadata when getMetadata() is called

In other words, don't automatically unserialize when the magic
phar:// stream wrappers are used.
RFC: https://wiki.php.net/rfc/phar_stop_autoloading_metadata

Also, change the signature from `getMetadata()`
to `getMetadata(array $unserialize_options = [])`.
Start throwing earlier if setMetadata() is called and serialization threw.

See https://externals.io/message/110856 and
https://bugs.php.net/bug.php?id=76774

This was refactored to add a phar_metadata_tracker for the following reasons:
- The way to properly copy a zval was previously implicit and undocumented
  (e.g. is it a pointer to a raw string or an actual value)
- Avoid unnecessary serialization and unserialization in the most common case
- If a metadata value is serialized once while saving a new/modified phar file,
  this allows reusing the same serialized string.
- Have as few ways to copy/clone/lazily parse metadata (etc.) as possible,
  so that code changes can be limited to only a few places in the future.
- Performance is hopefully not a concern - copying a string should be faster
  than unserializing a value, and metadata should be rare in most cases.

Remove unnecessary skip in a test(Compression's unused)

Add additional assertions about usage of persistent phars

Improve robustness of `Phar*->setMetadata()`

- Add sanity checks for edge cases freeing metadata, when destructors
  or serializers modify the phar recursively.
- Typical use cases of php have phar.readonly=1 and would not be affected.

Closes GH-5855

1 files changed, 2 insertions, 0 deletions

diff --git a/ext/standard/php_var.h b/ext/standard/php_var.h
index cab0f6d4dd..2d9f5464f5 100644
--- a/ext/standard/php_var.h
+++ b/ext/standard/php_var.h
@@ -59,6 +59,8 @@ PHPAPI zend_long php_var_unserialize_get_cur_depth(php_unserialize_data_t d);
 #define PHP_VAR_UNSERIALIZE_DESTROY(d) \
 	php_var_unserialize_destroy(d)
 
+PHPAPI void php_unserialize_with_options(zval *return_value, const char *buf, const size_t buf_len, HashTable *options, const char* function_name);
+
 PHPAPI void var_replace(php_unserialize_data_t *var_hash, zval *ozval, zval *nzval);
 PHPAPI void var_push_dtor(php_unserialize_data_t *var_hash, zval *val);
 PHPAPI zval *var_tmp_var(php_unserialize_data_t *var_hashx);