[DOXIA-554] Parsing Markdown documents can hang site generation: switch parser from Pegdown to Flexmark

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7
• Fix Version/s: 1.8
• Component/s: Module - Markdown
• Assignee: Herve Boutemy
• Reporter: Michael Benz
• Created: 03/Feb/17 17:21
• Updated: 12/Feb/20 17:52
• Resolved: 25/Mar/17 21:06

Description

The parsing time for Markdown documents can take very long and hang site generation when e.g. long tables are being generated.

The author of pegdown has marked the pegdown project deprecated since 2016-12-14 pegdown.org and advises to switch to flexmark-java.

The project is essentially unmaintained with tickets piling up and crucial bugs not being fixed.
pegdown's parsing performance isn't great. In some cases of pathological input runtime can even become exponential, which means that the parser either appears to "hang" completely or abort processing after a time-out.

Since the parsing timeout was increased in DOXIA-498 it is now possible to "hang" the site creation with a longer table like the one in this example.
In case this sample is rendered using version 3.3 of the maven site

Issue Links

• causes: DOXIA-571 Markdown does not support syntax highlighting any more
• is depended upon by: DOXIA-567 update dependency schema: pegdown not used any more but flexmark-java
• is related to: DOXIA-523 Ampersands after hash in markdown link syntax are now throwing parse errors.
• is related to: DOXIA-568 Doxia Markdown extension > Support for some MarkDown extensions has been removed since 1.7
• is required by: MSITE-791 upgrade Doxia to 1.8 to benefit from new Markdown parser (require Java 7)
• relates to: DOXIA-553 Replace pegdown due to deprecation and end of life notice