fix err: Regular expression "XXX" is not valid ("": regular expression is too large)

[xinghaiquedeng]

When libyang 2.1.55 is used to parse the yang file, the following error message is displayed:

Regular expression "((((6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}).(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}|0))|(([1-9]\d{0,8})|([1-3]\d{9})|(4[0-1]\d{8})|(42[0-8]\d{7})|(429[0-3]\d{6})|(4294[0-8]\d{5})|(42949[0-5]\d{4})|(429496[0-6]\d{3})|(4294967[0-1]\d{2})|(42949672[0-8]\d{1})|(429496729[0-5])))( ((6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}).(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}|0))| (([1-9]\d{0,8})|([1-3]\d{9})|(4[0-1]\d{8})|(42[0-8]\d{7})|(429[0-3]\d{6})|(4294[0-8]\d{5})|(42949[0-5]\d{4})|(429496[0-6]\d{3})|(4294967[0-1]\d{2})|(42949672[0-8]\d{1})|(429496729[0-5]))){0,255})" is not valid ("": regular expression is too large).

The same file is parsed using pyang. No error occurs.

[xinghaiquedeng]

The regular expression is as follows:
pattern '((((6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}).(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}|0))|(([1-9]\d{0,8})|([1-3]\d{9})|(4[0-1]\d{8})|(42[0-8]\d{7})|(429[0-3]\d{6})|(4294[0-8]\d{5})|(42949[0-5]\d{4})|(429496[0-6]\d{3})|(4294967[0-1]\d{2})|(42949672[0-8]\d{1})|(429496729[0-5])))( ((6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}).(6553[0-5]|655[0-2][0-9]|65[0-4][0-9]{2}|6[0-4][0-9]{3}|[1-5][0-9]{4}|[1-9][0-9]{0,3}|0))| (([1-9]\d{0,8})|([1-3]\d{9})|(4[0-1]\d{8})|(42[0-8]\d{7})|(429[0-3]\d{6})|(4294[0-8]\d{5})|(42949[0-5]\d{4})|(429496[0-6]\d{3})|(4294967[0-1]\d{2})|(42949672[0-8]\d{1})|(429496729[0-5]))){0,255})';

[michalvasko]

We are using PCRE2 for parsing there regular expressions. If it says it is too large then there is nothing we can do about it and it is a limitation of the implementation.

[xinghaiquedeng]

This is the PCRE2's response to this question：
PCRE2Project/pcre2#271

[michalvasko]

Okay, so make sure you are using 32b version of PCRE2. Nothing I can help you with.