Bug #77642: preg_match: Compilation failed: regular expression is too large at offset 27 - TYPO3 Core - TYPO3 Forge

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Bug #77642

closed

preg_match: Compilation failed: regular expression is too large at offset 27

Added by Tobias Schaefer about 8 years ago. Updated about 2 years ago.

Status:

Closed

Priority:

Must have

Assignee:

Category:

Frontend

Target version:

Start date:

2016-08-25

Due date:

% Done:

100%

Estimated time:

TYPO3 Version:

PHP Version:

7.2

Tags:

Complexity:

Is Regression:

Sprint Focus:

Description

If the cropHTML function (typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php) is called to crop at 1074 (or more) characters it fails with this error message:
PHP Warning: preg_match(): Compilation failed: regular expression is too large at offset 27 in typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php

Increasing pcre.backtrack_limit or pcre.recursion_limit in php.ini doesn't help.
To reproduce the bug you can use the news extension. Create a news with a teaser text of more the 1073 characters and set up the list plugin to crop the teaser text at 1074 characters. Cropping at 1073 characters will work.

Here you find a discussion about this problem:
http://stackoverflow.com/questions/31172837/regular-expression-is-too-large-error-in-php

Possible solutions:
- If you are trying to match/parse HTML, I would recommend using DOMDocument to parse the HTML and then walk the DOM tree or build an XPATH to find what you're looking for.
- Shorten the Regular Expression by using DEFINE for any redundant sub-expressions (see below).
- Split your regular expression at | and process the resulting sub-expressions separately. If the regex is essentially numerous keywords separated by |, then converting to a strtok or a loop with strpos may be a better & faster choice.

TYPO3: 6.2.26
PHP: 5.5.14
Linux: SLES 12 SP1

Cheers,
Tobias

Related issues 1 (0 open — 1 closed)

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Updated by Patrick Broens about 8 years ago

Seems to be still a problem in TYPO3 version 7.6.11. I can reproduce it in that version.

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Updated by Rémy DANIEL almost 8 years ago

I have this problem too: I'm am calling cropHTML with max 1500 chars.
Inside cropHTML, the pattern which try to find html entities ( #(&[^&\\s;]{2,8};|.){0,X}#uis ) blows up because of pcre LINK_SIZE.

This Stackoverflow post explains very well this limit: http://stackoverflow.com/a/33988643/1053453

But I am not a regex guru, so I don't know if this pattern could be optimised, or if another approach needs to be taken.

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Updated by Riccardo De Contardi about 6 years ago

I think it is still valid in TYPO3 8.7.19

My Test with a fresh 8.7.19 TYPO3 Installation:

1) On TS Setup write:

page.120 = TEXT
page.120.value (
 //Write here a very long text with 2000+ characters, I omit it here :)
) 
page.120.cropHTML = 964| ...

2) Go to frontend and refresh

Results:¶

1) In frontend, the text is not cropped

2) in TYPO3 Log module, you got 2 warnings:

Core: Error handler (FE): PHP Warning: preg_match(): Compilation failed: regular expression is too large at offset 26 in /TYPO3-dists/typo3_src-8.7.19/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php line 3752

Core: Error handler (FE): PHP Warning: preg_match(): Compilation failed: regular expression is too large at offset 26 in /TYPO3-dists/typo3_src-8.7.19/typo3/sysext/frontend/Classes/ContentObject/ContentObjectRenderer.php line 3746

With several trials I found that the "magic number" is 964; if you write page.120.cropHTML = 963| ... the crop works fine. I don't know if that depends on my environment settings.

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Updated by Susanne Moog over 4 years ago

Category set to Frontend

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Updated by Ian Solo over 4 years ago

Priority changed from Should have to Must have
TYPO3 Version changed from 6.2 to 11
PHP Version changed from 5.5 to 7.2

Still present in TYPO3 9 LTS and probably also in 10 LTS and current master since the code of method cropHTML didn't change.

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Updated by Gerrit Code Review about 3 years ago

Status changed from New to Under Review

Patch set 1 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/72048

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Updated by Gerrit Code Review about 3 years ago

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/72048

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