.json not translating Pattern correctly

[sepatel]

Something appears to be wrong with the way that .json is converting a Pattern object. We initially had done something like
collection.find("{authz: ${user.authz.toRegex().json}")
and found our code wasn't working as expected. Not a big deal, we googled up and figured out that we were idiots since mongo doesn't support Regex() it wanted Pattern(). So we tweaked the code up to do
collection.find("{authz: ${user.authz.toRegex().toPattern().json}")
and found it still didn't work.

After some deeper diving we found that using a Document("authz", user.authz.toRegex().pattern()) was working when using the native mongo java drivers. That let to some experiments where we discovered that the .json on the pattern doesn't convert things correctly.

val pattern = Pattern.compile("System#.*R")

Example of what creates a bad conversion

println("{authz: ${pattern.json}}")

Output: {authz: "System#.*R"}

Example of what creates a good conversion

println(Document("authz", pattern).json)

Output: {"authz": {"$regex": "System#.*R", "$options": ""}}

This happens in both 3.11.0 driver (what we currently have in production) and 3.12.2 driver (we should be able to upgrade to this if needed).

[zigzago]

Thanks for reporting. I'm going to fix the bug. There is a workaround. You can write:
collection.find("{authz: /System#.*R/}")

No need to compile a java Pattern or kotlin Regexp :)

[sepatel]

:) If I were hardcoding this specific thing sure, but its a variable coming from data model meaning that I then have to manually escape the regex pattern to try and protect from injection attacks or simply a regex pattern that has a / or other special character in it.

I think it would be best to wait for a fix and use a properly coded fix 👍