[VarExporter] a new component to serialize values to plain PHP code #28231

nicolas-grekas · 2018-08-19T18:38:03Z

Q	A
Branch?	master
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets	-
License	MIT
Doc PR	-

This PR proposes moving what is currently the PhpMarshaller class in the Cache component to a separate component.

This component would provide only one public static method:
VarExporter::export($value, bool &$isStaticValue = null): string.

This method returns $value serialized as plain PHP code. Running this code creates the same exact data structure that $value contained. This is exactly like serialize() and unserialize(), from which all semantics are preserved (__sleep, __wakeup and Serializable).

The reason to use this method vs serialize() or even igbinary is performance: thanks to OPcache, the resulting code is significantly faster and more memory efficient than using unserialize() or igbinary_unserialize().

Unlike var_export(), this works on any serializable PHP value.

It also provides a few improvements over var_export()/serialize():

the output is PSR-2 compatible
the output can be re-indented without messing up with any \r or \n in the data
missing classes throw a ReflectionException instead of being unserialized to a PHP_Incomplete_Class object
references involving SplObjectStorage, ArrayObject or ArrayIterator instances are preserved
Reflection*, IteratorIterator and RecursiveIteratorIterator classes throw an exception when being serialized (their unserialized version is broken anyway, see https://bugs.php.net/76737.)

tolry · 2018-08-20T07:58:00Z

since the naming is similar/identical it might be a good idea to distinguish this from the php core function http://php.net/manual/de/function.var-export.php ?

nicolas-grekas · 2018-08-20T11:41:52Z

@tolry we have the VarDumper component that provides a better var_dump() function. I think that the VarExporter name conveys what it should: this is a better var_export().

tolry · 2018-08-20T11:55:21Z

@nicolas-grekas I guessed so, just thought it might be easier to grasp, if the explanation mentioned var_export explicitely. Ah, I see it's in there now - did you add it or did I miss it before? 😁

nicolas-grekas · 2018-08-20T14:16:21Z

@tolry yes, I updated the description.

PR is ready IMHO.

sroze

Except these two comments, it looks good to me 👌

Note that it's very likely it will require more maintenance than when it was internal.

sroze · 2018-08-24T10:50:55Z

src/Symfony/Component/VarExporter/VarExporter.php

+use Symfony\Component\VarExporter\Internal\Exporter;
+use Symfony\Component\VarExporter\Internal\Reference;
+use Symfony\Component\VarExporter\Internal\Registry;
+use Symfony\Component\VarExporter\Internal\Values;

 /**
 * @author Nicolas Grekas <[email protected]>


We usually put that at the end of the comment.

sroze · 2018-08-24T10:52:25Z

src/Symfony/Component/VarExporter/composer.json

+    "name": "symfony/var-exporter",
+    "type": "library",
+    "description": "A blend of var_export() + serialize() to turn any serializable data structure to plain PHP code",
+    "keywords": ["export", "serialize"],


I'd add symfony and var-exporter as well, they are the component 💃

this is already in the name of the component, no need to duplicate

sroze · 2018-08-24T10:53:51Z

src/Symfony/Component/VarExporter/CHANGELOG.md

+4.2.0
+-----
+
+ * added the component


- * added the component + * Created the component (extracted `PhpMarshaller` from the `Cache` component)

Could be valuable to give a hint of where it comes from.

PhpMarshaller has never been released, better not give it any existence except in internal history
I'd keep as is :)

nicolas-grekas · 2018-08-24T11:31:55Z

Note that it's very likely it will require more maintenance than when it was internal.

That's why I added more tests for more cases (and fixes) ;)

Comments addressed, thanks for the review.

fabpot · 2018-08-27T16:14:59Z

src/Symfony/Component/VarExporter/README.md

+=====================
+
+The VarExporter component allows exporting any serializable PHP data structure to
+plain PHP code. While doing so, it preserves all the semantics associated to the


associated with

fabpot · 2018-08-27T16:15:14Z

src/Symfony/Component/VarExporter/README.md

+
+The VarExporter component allows exporting any serializable PHP data structure to
+plain PHP code. While doing so, it preserves all the semantics associated to the
+serialization mechanism of PHP (`__wakeup`, `__sleep`, `Serializable` esp.)


"esp" can be removed IMHO

fabpot · 2018-08-27T16:15:56Z

src/Symfony/Component/VarExporter/README.md

+Unlike `var_export()`, this works on any serializable PHP value.
+
+It also provides a few improvements over `var_export()`/`serialize()`:
+ * the output is PSR-2 compatible


missing empty line before the list, and missing ; at the end of each line but the last.

fabpot · 2018-08-27T16:16:04Z

src/Symfony/Component/VarExporter/README.md

+   instances are preserved
+ * `Reflection*`, `IteratorIterator` and `RecursiveIteratorIterator` classes
+   throw an exception when being serialized (their unserialized version is broken
+   anyway, see  https://bugs.php.net/76737.)


dot outside the parenthesis

extra space after "see"

fabpot · 2018-08-27T16:16:59Z

src/Symfony/Component/VarExporter/VarExporter.php

- * PhpMarshaller allows serializing PHP data structures using var_export()
- * while preserving all the semantics associated to serialize().
+ * VarExporter allows serializing PHP data structures to plain PHP code (like var_export())
+ * while preserving all the semantics associated to serialize() (unlike var_export()).


associated with

fabpot · 2018-08-27T16:17:26Z

src/Symfony/Component/VarExporter/VarExporter.php

+     *
+     * @return string The value exported as PHP code
+     *
+     * @throw \Exception When the provided value cannot be serialized


nicolas-grekas · 2018-08-27T16:34:39Z

Comments addressed thanks.

fabpot · 2018-08-27T16:42:30Z

Thank you @nicolas-grekas.

…lain PHP code (nicolas-grekas) This PR was merged into the 4.2-dev branch. Discussion ---------- [VarExporter] a new component to serialize values to plain PHP code | Q | A | ------------- | --- | Branch? | master | Bug fix? | no | New feature? | yes | BC breaks? | no | Deprecations? | no | Tests pass? | yes | Fixed tickets | - | License | MIT | Doc PR | - This PR proposes moving what is currently the `PhpMarshaller` class in the Cache component to a separate component. This component would provide only one public static method: `VarExporter::export($value, bool &$isStaticValue = null): string`. This method returns `$value` serialized as plain PHP code. Running this code creates the same exact data structure that `$value` contained. This is exactly like `serialize()` and `unserialize()`, from which all semantics are preserved (`__sleep`, `__wakeup` and `Serializable`). The reason to use this method *vs* `serialize()` or even igbinary is performance: thanks to OPcache, the resulting code is significantly faster and more memory efficient than using `unserialize()` or `igbinary_unserialize()`. Unlike `var_export()`, this works on any serializable PHP value. It also provides a few improvements over `var_export()`/`serialize()`: - the output is PSR-2 compatible - the output can be re-indented without messing up with any `\r` or `\n` in the data - missing classes throw a `ReflectionException` instead of being unserialized to a `PHP_Incomplete_Class` object - references involving `SplObjectStorage`, `ArrayObject` or `ArrayIterator` instances are preserved - `Reflection*`, `IteratorIterator` and `RecursiveIteratorIterator` classes throw an exception when being serialized (their unserialized version is broken anyway, see https://bugs.php.net/76737.) Commits ------- 7831ad7 [VarExporter] a new component to serialize values to plain PHP code

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[VarExporter] a new component to serialize values to plain PHP code

7831ad7

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fabpot merged commit 7831ad7 into symfony:master Aug 27, 2018

weaverryan mentioned this pull request Aug 28, 2018

New VarExporter Component symfony/symfony-docs#10230

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nicolas-grekas deleted the var-exporter branch August 30, 2018 15:24

nicolas-grekas modified the milestones: next, 4.2 Nov 1, 2018

This was referenced Nov 3, 2018

Release v4.2.0-BETA1 #29072

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[VarExporter] a new component to serialize values to plain PHP code #28231

[VarExporter] a new component to serialize values to plain PHP code #28231

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[VarExporter] a new component to serialize values to plain PHP code #28231

[VarExporter] a new component to serialize values to plain PHP code #28231

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